CHAPTER 3 

Issue Category: Antidegradation

Pages 3-138 – 3-289

Response to Public Comments

Water Quality Standard Regulatory Revisions

August, 2015

40 CFR Part 131

Docket #: EPA-HQ-OQ-2010-0606

This document is part of a larger document.
Chapter 3 – Response Essays 7.a – Antideg – Gen Supp 

Essay 7.a – Antidegradation: General Support

The U.S. Environmental Protection Agency (EPA) agrees with commenters that high quality water is a 

precious resource and that maintaining high water quality is consistent with the intent and purpose of 

the Clean Water Act (CWA). EPA agrees that improving the Tier 2 review process will better protect high 

quality waters, which are important resources, consistent with the CWA intent and purpose. EPA agrees 

with commenters that it is important for states and authorized tribes to seek alternatives to degradation 

of high water quality.

EPA agrees with comments expressing that per CWA section 303, states and authorized tribes have 

primacy in developing and implementing water quality standards (WQS). EPA agrees that EPA’s proposal 

appropriately did not intrude on the specifics of antidegradation implementation. The final rule 

continues to provide states and authorized tribes with flexibility in most aspects of implementation.

EPA agrees with comments stating that EPA’s proposal added clarity and flexibility to the 

antidegradation review process.

EPA disagrees with some comments that expressed concern that EPA’s proposal preamble was an 

attempt to establish supplemental rules. The proposal preamble and the final rule preamble provide 

policy statements to accompany the regulatory text, and do not establish any independent binding 

rules. Only the regulation itself is legally binding. EPA also disagrees that “the current Tier 2 process 

frequently fails to protect high quality waters.” Prior to today’s rule, the Tier 2 regulations and process 

resulted in many protections for high quality waters. EPA is finalizing today’s rule to improve the Tier 2 

process and further enhance protection to high quality waters.

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Essay 7.b – Antidegradation: General Opposition

A. General Support

The U.S. Environmental Protection Agency (EPA) agrees with comments stating that the principle of 

antidegradation is necessarily inferred from the goals and mandates of the Clean Water Act (CWA). EPA 

agrees with comments that states’ and tribes’ antidegradation policies and antidegradation 

implementation methods should be readily available to the public and dischargers.

B. Comments That Additional Requirements at 131.12 Will Not Fix Uneven 

Implementation

EPA disagrees with commenters who argued that a national rule is not needed to address uneven and 

sometimes deficient implementation in states and tribes. EPA recognizes commenters’ points that state 

and tribal agencies face challenges such as resource constraints and differing priorities, and does not 

dispute these challenges. EPA’s revisions are partly intended to preserve mechanisms, such as the water

body – by – water body approach to identifying high quality waters, states and authorized tribes can 

utilize to most effectively use these limited resources in a manner consistent with the CWA. 

Commenters also stated that lack of EPA guidance was a reason for the uneven implementation. EPA 

agrees that implementation may improve if EPA provided additional guidance. EPA plans to enhance its 

guidance on antidegradation after the final rule is published. However, EPA disagrees that these specific

regulatory revisions are not necessary. EPA guidance would not establish requirements for states. 

However, with new regulatory requirements, states will be required to implement antidegradation in a 

manner consistent with the regulations.

Commenters did not provide specific reasons for asserting that any revisions to 131.12 would not lead 

to improvements in implementation. EPA’s view is that while resource constraints, priorities, and lack of 

guidance may contribute to uneven implementation, adding more detail to a few aspects of the federal 

antidegradation provisions will provide more clarity and therefore improve implementation in a 

streamlined and transparent manner. 

C. Comments That the Clean Water Act Is Sufficiently Protected

A commenter stated that the CWA is sufficiently protected with the current regulations and “proposed 

rule.” EPA is unclear what the commenter meant by “and proposed rule” but disagrees that the CWA “is 

sufficiently protected.” EPA’s view is that as water quality challenges and state antidegradation 

programs have evolved over time, the regulations must be revised to ensure that programs continue to 

provide the antidegradation protection envisioned under the CWA. In addition, the proposed rule was 

not legally binding, and thus provides no additional protection. EPA is therefore finalizing revisions to 

section 131.12 found in today’s final rule.

D. Comments That Antidegradation Implementation Is in the Water Quality 

Management Program, Not Water Quality Standards

A commenter expressed the view that the federal regulation should not require states and tribes to 

adopt their antidegradation implementation methods as water quality standards (WQS) because 

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implementation has been typically handled in the water quality management plans or proposed 

antidegradation rules (which are already evaluated by EPA). While some states may include their 

antidegradation implementation methods in the state water quality management plans, this is not a 

requirement in the federal regulations (See Title 40 of the Code of Federal Regulations (CFR) section

130.6). Likewise, not all states or authorized tribes adopt their antidegradation implementation 

methods into proposed rules that are evaluated by EPA. Regardless, EPA’s final rule does not require 

adoption of implementation methods as new or revised WQS. Today’s rule at section 131.5(a)(3) makes 

explicit EPA’s authority to review states’ and authorized tribes’ antidegradation policies and any 

adopted antidegradation implementation methods and to determine whether those policies and 

methods are consistent with section 131.12. Please see EPA’s final rule preamble section D, subsection 

titled Antidegradation Implementation Methods and response essay 7.f.i. for additional discussion.

E. Comments That Designated Uses Should Be Protective Enough

EPA disagrees with comments arguing that water bodies are adequately protected if the designated uses 

and “associated water quality standards” are attained and that an antidegradation program is not 

necessary to prevent degradation of a water body. Antidegradation provides protection beyond the 

protection provided by designated uses and water quality criteria. EPA’s proposal and final rule address 

enhancements to the specific part of an antidegradation program that protects high quality waters, 

therefore EPA will address these comments in that context. In waters with high water quality, the water 

quality is better than necessary to support protection and propagation of fish, shellfish, and wildlife and 

recreation in and on the water, (i.e., the CWA section 101(a)(2) goals) and is thus, in most cases, better 

than necessary to meet the designated uses and criteria. As discussed in the final rule preamble section 

D, this increment of “...high quality water provides a margin of safety that will afford the water body 

increased resilience to potential future stressors, including climate change”. The purpose of the 

antidegradation requirements at section 131.12(a)(2) is to ensure states and authorized tribes go 

through an informed and public decision-making process before allowing degradation of this water 

quality. Without such a process, high quality waters could be degraded from their current high quality 

down to the minimum required by the designated uses and criteria unnecessarily. A commenter stated 

that “minor degradation” where “water quality standards” are being met might have little or no impact 

on uses. In the context of the comment, it is unclear what is meant by “water quality standards” or 

“minor degradation.” In some instances, de minimis (i.e. insignificant) degradation may have little or no 

impact on the designated use if the water quality criteria is being met. However, as discussed earlier, the 

purpose of EPA’s revisions are to protect waters where the attained water quality is better than the 

CWA’s objectives unless the state makes a finding that degrading the water quality is necessary. While

de minimis degradation may not result in a failure to protect designated uses, it does cause loss of 

assimilative capacity of the water body and diminishes the water body’s resilience to future stressors.

Commenters also pointed out that the proposed rule did not define how much decline equals 

degradation. EPA’s regulations do not define “degradation” because it provides states and authorized 

tribes the discretion to address this question in their individual antidegradation programs. Some states 

and tribes define “degradation” formally and have antidegradation policies that specifically exempt 

discharges that would cause “insignificant degradation” from Tier 2 review. Please see EPA’s final rule 

preamble section D and response essay 7.i. for additional information on de minimis significance 

thresholds for antidegradation.

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F. Comments That EPA’s Proposal Is a Radical Revision Reversing Established 

Law

EPA disagrees with comments stating that EPA's proposed revisions to the antidegradation rule are a 

“radical revision of the current antidegradation rule” that reverses established law regarding 

antidegradation requirements. The proposed rule did not propose to and the final rule does not radically 

revise or reverse established federal antidegradation rules. The changes to 131.12 are consistent with 

the previous version of 131.12, while providing clarifying requirements to ensure that state and 

authorized tribes continue to develop and implement antidegradation programs consistent with the 

CWA and section 131.12 and with adequate public involvement. 

None of these revisions are radical. The water body- by-water body approach and parameter-byparameter approaches were discussed in the 1998 Advance Notice of Proposed Rulemaking (ANPRM), 

where EPA articulated that either approach, when properly implemented, is consistent with the CWA, 

and described advantages and disadvantages to both approaches. However, the Agency has found that 

it is possible for states and authorized tribes to identify high quality waters in a manner inconsistent 

with the CWA and the intent of EPA’s implementing regulations. Today’s rule reaffirms EPA’s support for 

both approaches, while ensuring that use of the water body - by - water body approach is consistent 

with the CWA.

The new regulatory requirement for an analysis of alternatives found at 40 CFR section 131.12(a)(2)(ii) is 

also not radical. A similar concept was considered and addressed in the water quality requirements for 

the Great Lakes states in 1995 (see 40 CFR part 132, Appendix E). 40 CFR part 132 Appendix E requires 

that any entity seeking to degrade high water quality must submit an antidegradation demonstration for 

consideration by the state. This demonstration includes an analysis identifying cost-effective pollution 

prevention alternatives and techniques, as well as an analysis identifying alternative or enhanced 

treatment techniques (and their relative costs) that are available to the entity and that would eliminate 

or significantly reduce the extent to which the increased loading results in a lowering of water quality.

Today’s final rule provides that before allowing a lowering of high water quality, states and authorized 

tribes must find, after an analysis of alternatives, that such a lowering is necessary to accommodate 

important economic and social development in the area in which the waters are located. That analysis 

must evaluate a range of non-degrading and less degrading practicable alternatives. 40 CFR 131.3(n) 

defines “practicable” to mean “technologically possible, able to be put into practice, and economically 

viable.” The requirement at 40 CFR 131.12(a)(2)(ii) provides transparency and consistency in states’ and 

authorized tribes’ decisions about high water quality. The new requirement makes the analysis of 

alternatives an integral part of a state’s or authorized tribe’s finding that degradation of high quality 

water is “necessary.” Such an analysis provides states and authorized tribes with a basis to make 

informed and reasoned decisions, assuring that degradation only occurs when truly necessary.

In regards to the antidegradation implementation methods, the new public involvement requirement is 

rooted in the CWA. As discussed in the preamble to the final rule, “CWA section 101(e) provides that 

‘public participation in the development, revision, and enforcement of any regulations, standard, 

effluent limitation, plan, or program established [...] under this Act shall be provided for, encouraged, 

and assisted [...].’ Thus, today’s rule also provides for public involvement during the development or 

revision of implementation methods.” It is reasonable to expect states and authorized tribes to involve 

their public when deciding how to protect the waters as such waters are a public resource. EPA’s 

regulations provide sufficient flexibility for the states and authorized tribes to decide the best way to 

effectively engage their own public where the implementation methods are not legally binding. Where 

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the methods are legally binding, the appropriate federal and state administrative procedures 

requirements apply.

G. Comments That EPA Based the Regulation on Faulty 

Assumptions/Rationales

Some commenters disputed EPA’s position in the proposal preamble that antidegradation is not being 

implemented as effectively as it could be. Specifically, commenters stated that the preamble to the 

proposal provided unsupported claims that the nation’s water quality is declining as a result of an 

“increasing degree of stress from anthropogenic influences” and that current antidegradation policies 

must be ineffective because there are increasing numbers of waters that are listed as impaired. 

Commenters said that EPA should not present that information as evidence that water quality is 

worsening, because the increasing number of impaired waters has other causes (e.g., monitoring has 

improved, assessment and modeling tools have improved, WQS have become more stringent, etc.). 

EPA’s preamble statement did not attribute the increasing number of impaired waters solely to deficient 

antidegradation implementation. As EPA stated in the proposal preamble, EPA received substantial 

feedback from stakeholders that existing CWA antidegradation regulatory provisions and related 

guidance have not been fully successful in ensuring consistent and effective implementation of Tier 2 

high quality water protections. EPA agrees that the increasing number of waters listed as impaired has 

many causes, including the causes cited by commenters. And EPA appreciates state efforts to improve 

monitoring and assessment. However, it is reasonable for EPA to use the increasing number of impaired 

waters (as well as feedback from stakeholders) as a basis for strengthening the Tier 2 regulations. EPA’s 

final rule represents an effort to strengthen the regulations to facilitate efforts to protect high quality 

waters. While commenters provided additional reasons for why additional waters have been listed 

under CWA section 303(d), the commenters do not refute that the nation’s waters are indeed being 

degraded nor do they provide evidence that today’s antidegradation programs are sufficient.

H. Comments That EPA Should Not Adopt Regulations That Infringe on State 

Primacy

Some commenters provided examples of how several states design their antidegradation 

implementation programs. These commenters maintained that states should be given more discretion in 

antidegradation implementation than EPA proposed. Other commenters maintained that state are in 

the best and primary position to exercise good, independent judgment to prevent degradation.

While states play a key role, EPA disagrees that the state alone is in the best and primary position to 

prevent degradation. The CWA gives EPA an important role in determining appropriate minimum levels 

of protection and providing national oversight. It also gives considerable flexibility and discretion to 

states and authorized tribes to design their own programs and establish levels of protection above the 

national minimum. EPA’s view is that the final regulation strikes the appropriate balance of preserving

state discretion with some boundaries to ensure that even utilizing its flexibility, states and authorized 

tribe’s programs will continue to be consistent with the CWA and the federal regulations. Some 

commenters argued that states are already implementing successful programs and that EPA should 

work collaboratively with states that are not adequately implementing antidegradation prior to (or

instead of) undertaking rulemaking. EPA agrees that it should work collaboratively with states that are 

not adequately implementing antidegradation, however it disagrees that such work must occur prior to

or instead of the revisions to section 131.12. EPA’s regulation is intended to provide transparent 

requirements so states and authorized tribes develop and implement antidegradation programs 

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consistent with the CWA and regulation. EPA cannot expect states to revise their programs if the federal 

requirements are not clear. Once EPA revises the rule, EPA will work with states and authorized tribes to 

ensure that adequate revisions are made, where necessary. Please see response essay 7.c for additional 

discussion.

Some commenters expressed that specific state antidegradation regulations that have already been 

developed with public involvement and approved by EPA as adequate and should not have to be 

revised. EPA disagrees. CWA section 303(c)(1) and the implementing regulations at 40 CFR 131.20 

require states and tribes to hold public hearings at least once every 3 years for the purpose of reviewing 

applicable WQS and, as appropriate, modifying and adopting standards. Federal, state and authorized 

tribal regulations are always evolving to keep pace with environmental and administrative challenges. It 

is unreasonable to expect that once a state’s or authorized tribe’s WQS are approved that such WQS will 

never again need to be revised. This practice would lead to state and authorized tribal WQS to quickly 

become obsolete and ineffective at protecting the waters in its jurisdiction for the use the state and 

authorized tribe itself has articulated as the desired condition. Therefore, EPA fully expects states to 

revise their antidegradation regulations and methods to ensure consistency with the final rule 

requirements. EPA does not expect such changes to occur instantaneously. EPA provides some 

flexibility, stating in its preamble that “EPA’s expectation is that, where a new or revised requirement 

necessitates a change to state or authorized tribal WQS, such revisions will occur within the next 

triennial review that the state or authorized tribe initiates after publication of this rule.” 

I. Comments That EPA’s Revisions Would Hugely Burden States and 

Permittees

Commenters expressed concern that the proposed changes to antidegradation requirements would 

greatly increase administrative burden on states and decrease the State’s ability to provide sound water 

quality management. EPA disagrees. Many states and authorized tribes will incur a one-time 

administrative burden to make changes to their regulations for consistency with the final rule. However, 

some states may face no additional burden. EPA has accounted for these costs in its economic analysis

(EA). Based on that analysis, those costs are not significant and EPA has finalized regulatory revisions 

that are necessary to ensure that sound water quality management decisions are made nationally. For

states and authorized tribes that currently have WQS that are consistent or mostly consistent with 

today’s rule, EPA expects that any revisions to those water quality will have minimal burden on the state 

and minimal impact on the state or authorized tribe’s decision making process.

EPA disagrees with comments stating that the rule will place excessive burden on permittees seeking 

authorization because permittees would not be allowed to increase any pollutants to a stream unless 

they demonstrated they were applying the most stringent wastewater technology that could be paid for 

by the company and no other project options were determined to be available that would decrease 

pollutant loading, including a reduced project scope or no project at all. The final requirement for 

alternatives analysis, like the proposed requirement, allows for considerable state and tribal discretion.

The rule does not require permittees to implement any alternative that is not “practicable,” nor are they 

required to implement the “least degrading” practicable alternative.

Please see response essay 12.a. for additional discussion on the administrative burden of this rule.

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J. Comments Questioning How Waters Can Be Both “High Quality” and 

“Impaired” Simultaneously

A commenter stated that the proposal would make antidegradation policies apply to many waters that 

are ‘impaired,’ making them both ‘high quality’ and ‘impaired’ at the same time. EPA agrees that it is 

possible for a water to be considered “high quality” (for purposes of Tier 2 of antidegradation) and 

“impaired” (by the 303(d) listing program) at the same time. For example, a water might be of high 

quality with respect to some chemical, physical, and biological parameters but impaired with respect 

to others. Tier 2 can provide protection for the high water quality that exists in the water body 

(e.g., assimilative capacity for some parameters), despite having impairments with respect to other 

parameters. CWA section 101(a) includes the objective to “restore and maintain the chemical, physical 

and biological integrity of the Nation’s waters.” The potential for a water to be both high quality and 

impaired is evident in this section of the CWA. This goal can only be met by restoring the Nation’s waters 

and by maintaining the chemical, physical and biological integrity which has been achieved. Restoration 

and maintenance may occur on a single waterbody for different parameters. Waiting to “maintain” 

water quality when a water body is completely unimpaired on every parameter would likely result in no 

waters eventually being restored.

To be clear, “antidegradation policies” do apply to impaired waters; for instance, Tier 1 of 

antidegradation applies to all waters of the U.S.

K. Comments That the Revisions Aren’t Protective Enough

EPA disagrees with comments stating that the proposal fell short of meeting the CWA’s objective of 

maintenance of high quality waters. EPA’s view is that the final regulation strikes the appropriate 

balance of providing appropriate boundaries to ensure that antidegradation programs are developed 

and implemented consistent with the CWA and regulations but also allows states and authorized tribes 

an appropriate level of discretion to make water quality management decisions that are case specific 

and appropriate for the state/tribe. EPA does not believe a one size fits all approach will lend itself to 

the most effective antidegradation program nor is it consistent with the CWA’s intent to provide states 

and authorized tribes a level of primacy to make their own specific decisions as long as they are 

consistent with the CWA requirements.

For comments that EPA should require states and authorized tribes to use a parameter by parameter 

approach when identifying high quality waters, please see response essay 7.d.ii. For comments that EPA 

should require states and authorized tribes to analyze the least degrading or non-degrading alternative 

for any determination that lowering water quality is necessary, please see response essay 7.e.ii and 

7.e.iv.

L. Comments That the Proposal Was Ambiguous

EPA agrees with commenters stating that more requirements are needed to ensure adequate protection 

of water quality. EPA considered comments arguing that the proposal was ambiguous or unclear, and 

disagrees that the proposal was ambiguous and unclear and did not give adequate guidance about how 

to conduct Tier 2 review. The proposal preamble provided additional explanation for the proposed 

requirements. EPA intentionally did not propose nor finalize detailed requirements for how to conduct a 

Tier 2 review, in order to continue to provide for state and tribal flexibility and innovation, provided that 

the basic requirements of Tier 2 protection are covered. EPA’s finalized revisions are focused on how 

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states and authorized tribes decide which waters are high quality, how they determine whether a 

lowering of water quality is “necessary” and ensuring that antidegradation implementation methods are 

developed and antidegradation related decisions are made taking into account public input. EPA intends 

to provide additional guidance on conducting Tier 2 reviews subsequent to the final rule. 

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Chapter 3 – Response Essays 7.c – Antideg – Guidance 

Essay 7.c – Antidegradation: Guidance

The U.S. Environmental Protection Agency (EPA) agrees with the comment that the principle of 

antidegradation is one of the most powerful, yet underutilized, components of states’ and tribes water 

quality standards (WQS), as evidenced, for example, by many states’ and tribes’ lack of waters protected 

as outstanding national resource waters (ONRWs), the growing number of impaired waters in the United 

States, and the EPA’s national Rivers and streams assessment. EPA also agrees with the observation that 

implementation methods are not consistent nationally, and that this inconsistency highlights the need 

for more guidance and oversight to ensure that the purpose of antidegradation is achieved. Today’s rule 

provides regulatory requirements that will promote consistency nationwide and allows for more public 

oversight and engagement. EPA intends to provide subsequent guidance after promulgation of the final 

rule. The comment specifically seeks guidance on antidegradation implementation for Tier 1 and for 

water quality trading. These topics are outside the scope of today’s rulemaking, therefore, EPA is not 

promulgating any rule provisions addressing Tier 1 or water quality trading programs. However, EPA will 

consider those as potential topics to address in subsequent guidance. Meanwhile, EPA suggests 

consulting available EPA resources on water quality trading at 

http://water.epa.gov/type/watersheds/trading.cfm. 

A comment suggests that instead of promulgating regulatory revisions, EPA should work closely with 

states to determine why implementation is lacking in order to find solutions (presumably nonregulatory). It further suggests that the problem of some states not implementing, or inadequately 

implementing, antidegradation can be addressed by clearer EPA guidance. While EPA agrees that 

additional guidance can only be helpful and that the Agency should work collaboratively with States and 

authorized tribes, EPA disagrees that it is necessary to do these before revising the regulations. As 

discussed in response essay 7.b., EPA’s regulation is intended to provide transparent requirements so 

states and authorized tribes develop and implement antidegradation programs consistent with the 

Clean Water Act (CWA) and regulation. EPA cannot expect states to revise their programs if the federal 

requirements are not clear about what is necessary. Once EPA revises the rule, EPA will be better 

equipped to work with states and authorized tribes to ensure that adequate revisions are made, where 

necessary. 

EPA established its modern WQS regulation in 1983, and EPA has provided guidance in the form of the 

WQS Handbook and various memos and other documents since 1983 which are all available on EPA’s 

website at http://water.epa.gov/scitech/swguidance/standards/library/index.cfm. In addition, EPA 

Regions work individually with states and authorized tribes when they have specific questions or 

difficulties with developing or revising their antidegradation programs. Again, EPA does plan to provide 

updated guidance subsequent to the final rule, so that the guidance can incorporate elements related to 

the revised regulations. 

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Essay 7.d – Antidegradation: Identification of High Quality Waters

No comments are assigned to this issue category, and thus no response is necessary.

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Essay 7.d.i – Antidegradation and High Quality Waters: General Support

for Proposed Revision

A. Support for EPA’s Proposal

The U.S. Environmental Protection Agency (EPA) considered comments supporting the proposed 

language regarding identification of high quality waters for Tier 2 protection. EPA also considered 

comments stating that how states identify waters for Tier 2 protection is a key issue. EPA agrees with 

these comments.

A commenter stated that the proposal addresses the concern that states and tribes in the past have 

identified a water body not as a high quality water, specifically on the basis that the water body did not 

satisfy all the uses specified in the Clean Water Act (CWA) section 101 (a) (2). The comment states that 

the practice that may be based on a mere technicality seems to be against congress' intent, as a water 

body that exceeds most of the uses specified but may be slightly under the threshold for one use would

thus become excluded from the Tier 2 designation, and the higher protection afforded due to that 

designation. Given the overall purpose of the CWA and Congress' intent to “restore and maintain the 

chemical, physical, and biological integrity of the Nation's waters” (CWA section 101 (a)), it is clear that 

those water bodies with quality that exceed the levels necessary to support propagation of fish, 

shellfish, and wildlife and recreation in and on the water, should be given the Tier 2 designation.

EPA agrees with the comment that it is important to take a holistic evaluation of the water body itself, 

to evaluate all the chemical, biological, and physical characteristics in an effort to achieve the overall 

goal of the CWA. Other commenters reiterated the importance of a holistic evaluation of the water body 

and stated that that the proposal would result in Tier 2 protection for an increased number of deserving 

waters. The preamble to the final rule explains the holistic evaluation: “To make a decision to exclude a 

water body from Tier 2 protection, states and authorized tribes must identify the factors considered 

which should include factors that are rooted in the goals of the CWA, including the chemical, physical, 

and biological characteristics of a water body. Where states and authorized tribes wish to consider CWA 

section 303(d) listed impairments, it would be important that they also consider all other relevant 

available data and conduct an overall assessment of a water’s characteristics. It would also be important 

that states and authorized tribes consider the public value of the water. This includes the water’s impact 

on public health and welfare, the existing aquatic and recreational uses, and the value of retaining 

ecosystem resilience against the effects of future stressors, including climate change...The rule provides 

for a decision-making process where states and authorized tribes consider water quality and reasons to 

protect water quality more broadly. This can lead to more robust evaluations of the water body, and 

potentially more waters receiving Tier 2 protection.” 

EPA agrees that a holistic evaluation will provide Tier 2 protection for an increased number of waters 

that are high quality for certain parameters (while not high quality for other parameters). EPA found 

that without a change to the regulation, states or authorized tribes could decline to provide Tier 2 

protection for waters that could otherwise be considered high quality, without any reason other than 

the fact that it is listed pursuant to CWA section 303(d) for one parameter, and without any opportunity 

for public involvement on that decision. Maintaining the status quo would be contrary to the 

environmental goal for this rule which is to enhance the antidegradation requirements to promote more 

effective and widespread protection of high quality waters in order to maintain resilience to future 

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environmental and anthropogenic stressors. EPA also agrees with the comment that the proposal would 

have codified (and the final rule does codify) the flexibility to use the water body-by-water body 

approach.

Multiple commenters agreed with EPA’s proposal to explicitly allow states and authorized tribes the 

flexibility to identify waters for Tier 2 protection on a parameter-by-parameter or a water body-bywater body basis. Commenters said that the final rule should allow states and authorized tribes the 

discretion to use either method. Commenters stated that EPA correctly referred to states’ and 

authorized tribes’ primary role in developing and implementing their water quality standards (WQS) 

under CWA 303, and that EPA’s proposal preserved discretion regarding identification of high quality 

waters. Commenters pointed out that EPA’s proposal generally tracked the rationale of the federal 

courts that have affirmed the water body-by-water body option on the basis of an overall holistic 

assessment. 

Some commenters stated that the mechanism by which waters receive Tier 2 protection on a water 

body-by-water body basis should be at the state or authorized tribe’s discretion. EPA received 

comments describing specific state approaches (for example, using biological criteria to determine the 

subcategories of aquatic life uses). EPA agrees that the precise mechanism for identifying waters for Tier 

2 protection is at the discretion of the states and authorized tribes, provided protection is provided 

consistent with the final rule requirements. EPA continues to recognize states’ and authorized tribes’ 

discretion to use a water body-by-water body approach to prioritize their resources, understanding that 

those decisions may be based on considerations not limited to water quality alone. EPA’s view is that it 

is possible to use a water body-by-water body approach in ways that are consistent with the CWA and 

Federal WQS regulation. EPA recognizes that there may be multiple ways for a state or authorized tribe 

to develop a water body-based approach consistent with the goals of the CWA and the antidegradation 

regulation, and that many states and authorized tribes effectively use the water body-by-water body 

approach to prioritize waters for protection under section 131.12(a)(2).

Commenters stated that states and authorized tribes should have the flexibility to use CWA 303(d) lists 

(impaired waters lists) as part of the process of identifying waters that will and waters that will not 

receive Tier 2 protection. EPA agrees that 303(d) lists can provide useful information to help make such 

decisions. EPA’s view is that using data from 303(d) lists to identify for Tier 2 protection (or for exclusion 

from Tier 2 protection) can be consistent with the final rule, provided states and authorized tribes do 

not exclude waters from Tier 2 protection solely because water quality does not exceed levels necessary 

to support all of the uses specified in section 101(a)(2) of the Act. As explained in the preamble to the 

final rule, “...when considering whether to exclude waters from Tier 2 protection, states and authorized 

tribes must consider the overall quality of the water rather than whether water quality is better than 

necessary for individual chemical, physical, and biological parameters to support all the uses specified in 

CWA section 101(a)(2). The rule provides for a decision-making process where states and authorized 

tribes consider water quality and reasons to protect water quality more broadly. This can lead to more 

robust evaluations of the water body, and potentially more waters receiving Tier 2 protection. To make 

a decision to exclude a water body from Tier 2 protection, states and authorized tribes must identify the 

factors considered which should include factors that are rooted in the goals of the CWA, including the 

chemical, physical, and biological characteristics of a water body. Where states and authorized tribes 

wish to consider CWA section 303(d) listed impairments, it would be important that they also consider 

all other relevant available data and conduct an overall assessment of a water’s characteristics. It would 

also be important that states and authorized tribes consider the public value of the water. This includes 

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the water’s impact on public health and welfare, the existing aquatic and recreational uses, and the 

value of retaining ecosystem resilience against the effects of future stressors, including climate change.” 

Some commenters supported EPA’s proposal because even waters that may be listed on a 303(d) list as 

impaired for certain parameters would still be able to receive Tier 2 protection. They stated that this 

would be consistent with the intent of the CWA, since many water bodies impaired due to parameters 

such as mercury and PCBs may otherwise be high quality and worthy of Tier 2 protection. EPA agrees 

that excluding a water body from Tier 2 protection because it did not attain only one of the uses 

specified in section 101 (a) (2), would allow a potential categorical exclusion of most of the water bodies 

of the U.S., which would be inconsistent with the purpose of the antidegradation requirements. For 

comments that “disagree with the proposition that a state must consider as high quality a water that is 

specifically regulated as “impaired” by EPA” and that “States should be allowed to determine what level 

of review is appropriate for impaired waters”, please see the responses elsewhere in this essay and in 

response essay 7.b., section J for additional discussion.

EPA considered comments stating that specific states identify high quality waters on a water body-bywater body basis such that all waters receive Tier 2 protection at a minimum. EPA supports this 

approach as it is consistent with the intent of the antidegradation requirements, and encourages states 

and authorized tribes to consider broad application of Tier 2 protection, particularly where data may be 

limited. As discussed in EPA’s preamble to the final rule, in instances where states and authorized tribes 

lack data and information on the water quality to make individual water body conclusions, EPA 

recommends that they provide all or a subset of their waters with Tier 2 protection, by default. Doing so 

will increase the probability that these waters will maintain a level of resiliency to future stressors. EPA 

points out, however, that the federal rule does not require states and authorized tribes to provide Tier 2 

protection to all waters.

A commenter requested clarity over whether EPA’s proposal intended to require states and authorized 

tribes to establish the antidegradation tier for each applicable CWA 101(a)(2) use. For example, could a 

state or authorized tribe classify a water body as Tier 1 for protection of recreation in and on the water, 

but Tier 2 for aquatic life protection? The final rule requires that “...the State shall not exclude a water 

body from the protections described in (a)(2) of this section solely because water quality does not 

exceed levels necessary to support all of the uses specified in section 101(a)(2) of the Act.” For a 

discussion regarding a “use-by-use” approach, please see response essay 7.d.ii.

For a response to comments regarding state and authorized tribal discretion on how to conduct Tier 2 

reviews, please see response essay 7.d.iii.

B. Disagreement with Proposal and/or Suggestions for Changes

A commenter stated that the proposed regulation could be interpreted to require a state that previously 

identified all waters for Tier 2 protection to remove Tier 2 protection from some of those waters. The 

comment suggested that the final regulation acknowledge that treating all waters as Tier 2 would meet 

the requirements of the regulation. EPA is not including a statement about this particular situation in the 

regulation because it was not a necessary clarification to make within the regulation. EPA agrees that

treating all waters as Tier 2 would meet the requirements of the regulation as discussed in section A of 

this essay. Such an approach is also consistent with CWA section 510 and section 131.4. 

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Commenters stated that the mandatory limitation on the water body-by-water body method (requiring 

that waters not be denied Tier 2 protection solely because not all of the uses specified in CWA 101(a)(2) 

are attained) is unnecessary and improperly intrudes on states’ primacy in WQS. One commenter 

suggested that while not the best or most appropriate mechanism, EPA could “disapprove the state’s 

action under the auspices of reviewing the state’s standards submittal.” EPA disagrees as EPA only has 

the authority to review and approve or disapprove new or revised WQS. EPA could not “disapprove” any 

submittal if there was a concern with whether or not a state provided Tier 2 protection at the time of 

authorizing a lowering of water quality. Other commenters suggested that instead of promulgating a 

final rule addressing identification of waters for Tier 2 protection, EPA and third parties have the ability 

to address or challenge a permit that unnecessarily denies Tier 2 protection as part of the permit 

process. Commenters suggested that this would be a better and more direct option than revising the 

WQS regulation because it respects state discretion in identifying waters for Tier 2 protection while also 

protecting against error at the point when those decisions are applied. While EPA agrees that it is 

possible for EPA to exercise its oversight authority over permits and for third parties to challenge 

permits, EPA disagrees that the best and most direct option for ensuring that Tier 2 is applied 

appropriately is through permit challenges. EPA may object to a permit if the water quality-based 

effluent limit (WQBEL) does not derive from and comply with the applicable WQS. If the applicable WQS 

does not provide specific guidelines for when a water will be provided Tier 2 protection versus not, it 

would be difficult for EPA to say that denying Tier 2 protection in a particular instance does not derive 

from and comply with the applicable WQS. Thus EPA’s regulation specifically provides the limitation in 

federal regulation and state and authorized tribal antidegradation requirements must be consistent with 

the federal regulation. In addition, EPA’s rule requires that states and authorized provide an opportunity 

for public involvement in each decision, when using a water body – by – water body approach. With 

such a requirement, the only opportunity for public involvement on state and authorized tribal decisions 

about providing waters with Tier 2 protection would be in the public notice for a permitted or licensed 

activity that would lower water quality. This would deprive the public of the chance to influence the 

decision of whether to provide Tier 2 protection long in advance of a potential activity. Finally, permit 

objections are an inefficient means for EPA to ensure that water quality is protected. EPA is providing

antidegradation regulations that enhance the protection of high quality waters and promote consistency 

in implementation with the intention of avoiding individual permit objections (where possible) in order 

to provide certainty to the dischargers and reduce the unnecessary loss of limited resources.

A comment requested that EPA amend the regulation to require that EPA’s proposed high quality waters 

identification be applied to all Tier 2 and Tier 2.5 waters. The comment stated that states and authorized 

tribes must use all relevant water quality data and information to conduct an overall holistic assessment 

of the characteristics of Tier 2 and Tier 2.5 waters to determine whether a water body would receive 

Tier 2 or Tier 2.5 protection, and at a minimum must consider the factors EPA listed in the proposal to 

the preamble (e.g., existing aquatic uses, overall value and significance of the water body). The final rule 

requirement does not explicitly require states and authorized tribes to evaluate all relevant data and 

information to conduct a holistic assessment to determine whether a water body would receive Tier 2 

protection. Rather, the final rule at section 131.12(a)(2)(i) requires that “...the State shall provide an 

opportunity for public involvement in any decisions about whether the protections described in (a)(2) of 

this section will be afforded to a water body, and the factors considered when making those decisions.” 

EPA’s preamble, however, speaks to the importance of considering all other relevant data when 

conducting an overall assessment. When excluding waters from Tier 2 protection, the final rule requires 

that states and authorized tribes not exclude a water from Tier 2 solely because water quality does not 

exceed levels necessary to support the CWA 101(a)(2) uses. As discussed in the preamble, since 

exclusion cannot be based on the single factor of the water not supporting a 101(a)(2) use, EPA expects 

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the state or authorized tribe to do an overall assessment. EPA’s preamble specifically says “...when 

considering whether to exclude waters from Tier 2 protection, states and authorized tribes must 

consider the overall quality of the water rather than whether water quality is better than necessary for 

individual chemical, physical, and biological parameters to support all the uses specified in CWA section 

101(a)(2). The rule provides for a decision-making process where states and authorized tribes consider 

water quality and reasons to protect water quality more broadly. This can lead to more robust 

evaluations of the water body, and potentially more waters receiving Tier 2 protection. To make a 

decision to exclude a water body from Tier 2 protection, states and authorized tribes must identify the 

factors considered which should include factors that are rooted in the goals of the CWA, including the 

chemical, physical, and biological characteristics of a water body. Where states and authorized tribes 

wish to consider CWA section 303(d) listed impairments, it would be important that they also consider 

all other relevant available data and conduct an overall assessment of a water’s characteristics. It would 

also be important that states and authorized tribes consider the public value of the water. This includes 

the water’s impact on public health and welfare, the existing aquatic and recreational uses, and the 

value of retaining ecosystem resilience against the effects of future stressors, including climate change. 

For additional information on this overall assessment, see the preamble to the proposed rule at 78 FR 

54527 (September 4, 2013).” As for applying the federal requirements to Tier 2.5, the federal regulation 

does not contain a “Tier 2.5” requirement, though EPA recognizes that some states and authorized 

tribes use this concept to describe protection that is more protective than Tier 2 and less protective than 

Tier 3 for state and authorized tribal waters. EPA expects that states’ and authorized tribes’ 

requirements for Tier 2.5 be at least as protective as Tier 2 and thus be consistent with the requirements 

at section 131.12(a)(2). 

Commenters stated that states and authorized tribes should have discretion on which waters to identify 

as Tier 2 waters. EPA agrees that states and authorized tribes have discretion to determine which waters 

to provide Tier 2 protection, however EPA disagrees that the agency does not have a formal approval or 

disapproval process. As discussed in response essays 7.f.i and 7.f.ii and other response essays, EPA’s 

authority to review and approve or disapprove under CWA section 303(c) along with the factors the 

agency considers when determining whether a state provision is a new or revised WQS is discussed in its 

2012 frequently asked questions (FAQs) titled “What is a New or Revised WQS under CWA section 

303(c)(3)” found at http://water.epa.gov/scitech/swguidance/standards/cwa303faq.cfm. Therefore, 

where a state or authorized tribe identifies waters for Tier 2 protection in their legally binding WQS 

(e.g., in their antidegradation policy or legally binding implementation methods), EPA does have 

authority to take 303(c) action on those decisions (when they are new or revised). However, the federal 

regulations do not require states and authorized tribes to adopt such decisions into their regulations. 

The final rule requires that states’ and authorized tribes’ legally binding antidegradation policies be 

consistent with the final rule requirements for identifying waters for Tier 2 protection. 

A comment requested that EPA consider amending paragraph (b)(1) and “Water Quality Guidance for 

the Great Lakes System” to provide that high quality waters are identified on a designated use basis, 

rather than a parameter-by-parameter basis. EPA’s regulation allows the water body-by-water body 

approach because it can be implemented consistent with the intent of the CWA. EPA’s view is that the 

final rule allows flexibility for states and authorized tribes to consider specific suites of parameters, 

provided they explain the factors considered to the public, and do not exclude waters from Tier 2 

protection solely because not all of the CWA 101(a)(2) uses are met. For a discussion on a use-by-use 

approach, please see response essay 7.d.ii. The “Water Quality Guidance for the Great Lakes System” is 

outside the scope of this rulemaking because EPA did not propose any revisions to Part 132 of the 

regulations. 

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A comment stated that for water-rich states, using a parameter-by-parameter approach is problematic 

because in-stream monitoring data may not be available for all parameters. If a parameter-byparameter approach is continued, the comment requested EPA provide clarification on how to make 

these determinations absent in-stream data. The final rule provides that states and authorized tribes 

may identify waters for Tier 2 protection on either a parameter-by-parameter or water body-by-water 

body basis. The rule reaffirms EPA’s support for both approaches. Thus, where states do not have 

adequate data to use the parameter-by-parameter approach, states and authorized tribes have the 

discretion to use the water body-by-water body method where appropriate. While the final rule does 

not address questions of decision-making when using the parameter-by-parameter approach in the 

absence of data, EPA will consider providing more information on this issue as the Agency develops 

additional antidegradation guidance subsequent to the final rule.

C. Comments regarding the Difference between “Uses Specified in Clean Water 

Act Section 101(a)(2)” and “Protection and Propagation of Fish, Shellfish, and 

Wildlife and Recreation in and on the Water” 

EPA received comment that said “Also, the purpose of the anti-degradation requirement is to protect 

those waters with a quality higher than necessary to ‘support propagation of fish, shellfish, and wildlife 

and recreation.’ 40 C.F.R. §131.12(a)(2). In this regard, EPA suggests an alternative stating that ‘Tier 2

reviews are only required for parameters associated with 101(a)(2) [of the Clean Water Act]’ – the 

paragraph that sets out Congress’ ‘fishable and swimmable’ goal.” The commenter stated that they 

supported the alternative. The commenter appears to be referring to the proposal preamble where EPA 

asked for comment about the following alternative: “Alternatively, the EPA could specify that for waters 

identified as high quality on a water body-by-water body basis, Tier 2 reviews are only required for 

parameters associated with the 101(a)(2) uses currently being supported. For example, in Water Body B 

above, [a hypothetical water body supporting CWA 101(a)(2) recreational uses but not aquatic life uses] 

a Tier 2 review would only be required for each parameter that is better than the applicable criteria to 

protect recreation. And, a Tier 2 review would not be required for any parameter only associated with 

the aquatic life use (i.e., and not also associated with the recreation use).” 78 FR 54528, second column. 

EPA did not include the alternative described in the proposal preamble in the final rule. Although EPA 

considered this approach and the comments that supported the approach, EPA did not finalize this 

alternative for reasons explained in response essay 7.d.iii (“Antidegradation High Quality Waters Tier 2 

Review”) section A for more discussion.

D. Comments regarding Determining When an Activity “Accommodates 

Important Economic or Social Development” 

For a response to these comments, please see response essay 7.e.ii, section J.

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Essay 7.d.ii – Antidegradation and High Quality Waters: General 

Opposition for Proposed Revision

A. Support for Protection of High Quality Waters

The U.S. Environmental Protection Agency (EPA) received and agrees with comments supporting the 

protection of high quality waters. EPA agrees that protection of high quality waters is important, and 

discussed the reasons for this in the preamble to the proposed rule. Further, EPA agrees with comments 

pointing out that protecting high quality waters will help states and authorized tribes continue to strive 

towards the Clean Water Act (CWA) goals, and is be central to supporting both economic and 

community growth and sustainability.

B. Opposition to Proposal Because It Does Not Require Parameter-ByParameter, or Is Not Protective Enough

Comments provided on specific water bodies as far as whether they should or should not be identified 

as high quality waters (i.e., receive Tier 2 protection), and comments provided on specific states’ and 

authorized tribes’ approaches are outside the scope of this rulemaking. This is a national rulemaking and 

EPA is not finalizing (and did not propose) a rule that speaks to specific status of particular waters. States 

and authorized tribes have the responsibility and discretion to determine if waters receive Tier 2 

protection as long as the state or authorized tribe is consistent with the regulations. EPA will work with 

states and authorized tribes to determine whether and what revisions are necessary for state and 

authorized tribal antidegradation programs to be consistent with the regulations after publication. 

EPA disagrees with comments stating that the purpose of antidegradation is to provide the greatest 

protection for water quality possible, and that since the parameter-by-parameter method best achieves 

this, it should be required. The antidegradation provisions in the water quality standards (WQS) 

regulation are not intended to require the greatest protection possible for water quality. Title 40 of the 

Code of Federal Regulations CFR section 131.12(a)(1), or Tier 1, provides protection for existing uses for 

all waters. 40 CFR section 131.12(a)(2), or Tier 2, provides a decision-making process for states and 

authorized tribes to use when deciding whether to allow lowering of water quality (and how much to 

allow) up to the water quality criteria levels adopted to protect the designated use. 40 CFR section

131.12(a)(3), or Tier 3, provides a mechanism for states and authorized tribes to identify waters for 

which they will not allow any degradation. 40 CFR section 131.12(a)(4) coordinates requirements for 

thermal discharges with the requirements of CWA 316. Antidegradation provides these four different 

types of protection, only one of which (Tier 3) provides the greatest protection possible by prohibiting 

any degradation for those waters. The final rule only changes requirements related to Tier 2, which is 

not intended to prohibit degradation in those waters but rather to ensure that state and authorized 

tribal decisions on whether and how much lowering to allow first goes through a public decision making 

process. 

EPA agrees with comments that the parameter-by-parameter method provides protection for high 

quality water for individual parameters that are meeting WQS. Comments stated that the purpose of 

antidegradation is to maintain and protect the uses specified in CWA section 101(a)(2) and for that 

reason EPA must require the parameter-by-parameter approach in order to ensure that waters that are 

better than any given WQS will be protected for those standards and cleaned up for the other. EPA 

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agrees that the purpose of antidegradation is to maintain and protect the 101(a)(2) uses. However, EPA 

disagrees that the Agency must require the parameter-by-parameter approach to fulfill the purposes of 

antidegradation. First, the WQS components that are intended to provide for the protection and 

propagation of the uses specified in CWA 101(a)(2) are designated uses (section 131.10) and criteria to 

protect those uses (section 131.11). The purpose of the antidegradation regulation is to maintain the 

chemical, physical, and biological integrity of the Nation’s waters (CWA section 101(a)). EPA implements 

CWA section 101(a) and the antidegradation requirements to maintain existing uses, protect waters that 

exceed levels necessary to support the uses specified in CWA section 101(a)(2) and to protect 

Outstanding National Resource Waters (ONRWs). Doing so supports economic and community growth 

and sustainability and provides a margin of safety that will afford the water body increased resilience to 

potential future stressors (See EPA’s preamble to the final rule for further discussion). EPA does not 

agree that the parameter-by-parameter method must be required because it ensures water bodies that 

are impaired for other parameters will be cleaned up. Tier 2 antidegradation, by definition, can only 

provide protection for high water quality where it exists. As stated in section 131.12(a)(2), high water 

quality exists where water quality exceeds levels necessary to support the uses specified in CWA section 

101(a)(2) (i.e., protection and propagation of fish, shellfish, and wildlife and recreation in and on the 

water). Where a water is impaired with respect to a particular parameter protecting a use specified in 

CWA 101(a)(2), no assimilative capacity is available for Tier 2 protection (i.e., the water quality does NOT 

exceed the levels necessary to support the uses specified in CWA 101(a)(2)) and thus a state or 

authorized tribe would not be required by section 131.12(a)(2) to conduct a Tier 2 review related to that 

parameter. Total maximum daily loads (TMDLs) are a more appropriate tool to plan for improving water 

quality with respect to the particular parameter for which the water is impaired.

The water body-by-water body approach allows states and authorized tribes to prioritize their resources 

by focusing on waters that the state or authorized tribe determines are most in need of protection. 

Commenters that support requiring the parameter-by-parameter method stated that their opposition to 

the water body-by-water body method was because it allows unnecessary degradation. The final rule 

allows states and authorized tribes to use the parameter-by-parameter method or to use the water 

body method with some specified limitations. The water body-by-water body method can be used 

consistently with the CWA, and the final rule provides limitations on the method to provide a balance 

between providing an approach that may be more practical for states and authorized tribes and 

ensuring consistency with the CWA.

EPA agrees with commenters’ statement that because some pollutants are pervasive and cause 

problems for meeting WQS in many waters, even waters that would otherwise be completely pristine 

might violate WQS for one or more parameters (e.g., mercury.) EPA agrees with commenters that a 

state or authorized tribe should not be allowed to apply lesser protections to what might otherwise be a 

high quality water simply because it exceeds a standard with respect to a single pervasive pollutant. The 

commenters stated that the proposal would allow states to claim that some waters are not of high 

quality based on impairment of only one parameter. EPA disagrees with this characterization and points 

out that it discusses this very issue on page 54527 of its proposal as EPA is explaining its rationale for the 

proposed limitation on the waterbody – by – waterbody approach. The proposal and the final rule 

specifically prohibit excluding waters from Tier 2 protection “solely because water quality does not 

exceed levels necessary to support all of the uses specified in section 101(a)(2) of the Act”. In other 

words, if a water is impaired only for mercury, this would mean that the water quality does not exceed 

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levels necessary to support an aquatic life1 use because the aquatic life is not safe for human 

consumption. EPA’s final rule does not prohibit states and authorized tribes from using 303(d) listings to 

inform their high quality water decisions. However, states and authorized tribes using 303(d) 

impairments to inform exclusion of waters from Tier 2 protection must also point to at least one other 

factor rooted in the goals of the CWA that supports the decision, and allow for public involvement 

before deciding to exclude a water from Tier 2 protection. Commenters stated that the water body-bywater body approach would be the antithesis of the principles of the CWA and antidegradation 

regulation, since waters will become more degraded rather than less. EPA disagrees. Neither the CWA 

nor the antidegradation regulation prohibit degradation of high quality waters unless the state or 

authorized tribe has decided to provide Tier 3 protection for a water body. The water body-by-water 

body method, when used consistently with the CWA and antidegradation regulation, provides 

protection to high water quality while allowing states and authorized tribes flexibility to manage their 

resources to protect the higher priority waters first. Please see response essay 7.d.iii for discussion on 

conducting Tier 2 reviews once a water body is identified as high quality.

EPA agrees with comments stating that the parameter-by-parameter method for identifying high quality 

waters for Tier 2 protection provides more waters with Tier 2 protection than the water body-by-water 

body method. This is because the parameter-by-parameter approach provides Tier 2 protection for 

every parameter for which assimilative capacity (water quality better than the levels needed to support 

CWA 101(a)(2) uses) exists, regardless of anything else. In other words, all waters that have at least one 

parameter with assimilative capacity, will be provided some level of Tier 2 protection.

EPA disagrees with comments stating that the word “levels” in 40 CFR. 131.12(a)(2) (“where the quality 

of the waters exceed levels necessary to support the protection and propagation of fish, shellfish, and 

wildlife and recreation in and on the water, that quality shall be maintained and protected...”) mandates 

the parameter-by-parameter approach. “Where the quality of waters exceed levels” can refer to water 

quality as viewed by looking at specific parameters exceeding levels, or looking at suites or groups of 

parameters exceeding levels, or looking at the uses being protected and whether water quality is 

generally better than that necessary to meet the uses specified in CWA section 101(a)(2). The provision 

can be interpreted multiple ways and does not mandate a parameter-by-parameter approach per se. On 

a related note, the final rule corrects a grammatical error so that the provision begins “Where the 

quality of the waters exceeds,” to clarify that it is the quality of the waters that exceeds, not the waters 

that exceed.

 

1 Reference to “aquatic life” here is for purposes of the example. EPA recognizes that some states associate 

protection of human health when consuming aquatic life to other CWA 101(a)(2) type uses, such as recreation in 

and on the water, or a separate fishing designated use. Any designated use protecting human health when 

consuming aquatic life is considered a use specified in section 101(a)(2).

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EPA agrees with comments that the parameter-by-parameter method can be easier to implement 

because determining whether high water quality exists for which to provide Tier 2 protection is a 

function of the activity that degrades water quality and the quality of the water in the water body, 

which can be identified on a case-by-case basis at the time additional degradation is proposed. EPA 

agrees with comments that the parameter-by-parameter method is a proven, accurate, science-based 

methodology. As commenters point out, for a state or authorized tribe to identify high water quality 

relative to what parameters would be degraded by a proposed activity using a water body–by–water 

body approach, the most accurate way would be to do an individualized evaluation of the water body 

with respect to the parameters that would be affected. EPA agrees with commenters that looking at Tier 

2 protection in this manner can make it challenging to compile a list of waters to receive Tier 2 

protection in advance, since it would be hard to know what the “high quality” is that needs protecting 

before knowing the proposed activity. EPA agrees that this can be a concern with the water body-bywater body approach. However EPA views that approach as an acceptable way to manage Tier 2 if a 

state or authorized tribe wants to use it and also points out an advantage of identifying a list of waters 

eligible for Tier 2 review is that the information is easily publicly accessible and transparent.

Some commenters stated their preference for the parameter-by-parameter approach because it 

conforms to the dictates of the CWA to eliminate discharges and protect from pollution. EPA agrees that 

the parameter-by-parameter approach is consistent with the CWA. Commenters further stated that the 

parameter-by-parameter approach conforms to antidegradation regulations by ensuring that waters 

that are better than any given WQS will be protected for those standards and cleaned up for the others. 

EPA agrees that the approach conforms to the federal regulation at 131.12, but does not agree with this 

characterization. The parameter-by-parameter approach provides Tier 2 protection for high water 

quality above and beyond the levels necessary to support the uses specified in CWA 101(a)(2), not high 

water quality with respect to any designated uses a state or authorized tribe might adopt. (States and

authorized tribes may adopt uses different from, and in addition to, those uses specified in CWA section

101(a)(2).) EPA agrees with the comment that allowing high water quality to degrade and then restoring 

it later can be more difficult and more expensive than protecting the high water quality to begin with, 

and can result in significant loss of aquatic benefits. EPA discusses this point in its preamble to the final 

rule.

Some commenters disagreed with EPA’s proposal to retain the water body-by-water body approach as 

less-favored but still allowed, because even though EPA proposed more limits and structure to the water 

body-by-water body approach, the proposed limits and requirements are vague. They argued that this 

vague policy requirement for a “holistic assessment” with a variety of factors that will result in confusion 

and error by the states, and even litigation. EPA’s view is that the final rule and preamble provide 

enough structure that they will not result in confusion and error, and will consider providing additional 

guidance in the future. EPA found that it was reasonable and protective of overall water quality is to 

allow some level of flexibility in the considerations that go into determining how to protect water 

quality. EPA determined that this flexibility is consistent with the CWA’s system of cooperative 

federalism and continues to provide states and authorized tribes with discretion to make water quality 

decisions. EPA’s rule is intended to allow that flexibility because it believes that it is possible to 

implement a water body–by–water body approach consistent with the CWA and regulations that 

effectively protects high water quality and is ready to work with states and authorized tribes to achieve 

this result.

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Some commenters objected to the factors EPA discussed in the preamble to the proposal as factors that 

a state or authorized tribe could consider in an overall holistic assessment of waters for inclusion in or 

exclusion from Tier 2 protection, because the factors included “the overall value and significance of the 

water body from an ecological and public-use perspective.” They said that this factor was vague and 

poorly worded, and likely to be cited as an excuse not to identify waters for Tier 2 protection by simply 

declaring any individual water body as not very important to public use. EPA has reworded the 

discussion in the preamble to the final rule in order to be clearer. The preamble to the final rule explains 

that: “...when considering whether to exclude waters from Tier 2 protection, states and authorized 

tribes must consider the overall quality of the water rather than whether water quality is better than 

necessary for individual chemical, physical, and biological parameters to support all the uses specified in 

CWA section 101(a)(2). The rule provides for a decision-making process where states and authorized 

tribes consider water quality and reasons to protect water quality more broadly. This can lead to more 

robust evaluations of the water body, and potentially more waters receiving Tier 2 protection. To make 

a decision to exclude a water body from Tier 2 protection, states and authorized tribes must identify the 

factors considered which should include factors that are rooted in the goals of the CWA, including the 

chemical, physical, and biological characteristics of a water body. Where states and authorized tribes 

wish to consider CWA section 303(d) listed impairments, it would be important that they also consider 

all other relevant available data and conduct an overall assessment of a water’s characteristics. It would 

also be important that states and authorized tribes consider the public value of the water. This includes 

the water’s impact on public health and welfare, the existing aquatic and recreational uses, and the 

value of retaining ecosystem resilience against the effects of future stressors, including climate change.” 

EPA considered the commenters’ concern that a state or authorized tribe could cite “public value” of the 

water as a reason for not providing Tier 2 protection, and thus the final rule requires public involvement 

on decisions regarding whether Tier 2 protection will or will not be provided.

Some commenters stated that the detail and amount of work inherent in applying the “holistic” factors 

necessary to use the water body-by-water body approach would require a level of vigilance by EPA 

(and citizens) that EPA has not demonstrated to date when monitoring state compliance with 

antidegradation requirements. EPA agrees that conducting a holistic assessment of a water body may 

take more effort than the parameter-by-parameter approach. This is because identifying high water 

quality with the parameter-by-parameter approach is solely based on evaluating the ambient level of 

water quality in the water body with respect to the parameters that would actually be discharged, 

rather than evaluating multiple factors in a holistic assessment. However, looking at the water body 

holistically is consistent with the CWA goal of maintaining the chemical, physical AND biological integrity 

of the nation’s waters. EPA disagrees that because the waterbody by waterbody method may require 

more effort means that the approach should be prohibited and disagrees that more oversight is needed 

than EPA already provides. EPA’s role in monitoring compliance and enforcement of activities subject to 

antidegradation requirements remains unchanged by this rulemaking. This means it is still limited 

(e.g., when states or authorized tribes implement antidegradation requirements for activities that are 

not regulated) and discretionary (e.g., for antidegradation implementation in National Pollutant 

Discharge Elimination System [NPDES] permits). The purpose of this rulemaking is to enhance protection 

of high quality waters, provide more consistent implementation and provide transparency to the public. 

The regulation will benefit states, the public, regulated entities, and EPA in its oversight role. With these 

revisions, the Agency’s intention is to prevent unnecessary litigation.

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Some comments stated that if EPA declines to prohibit the water body-by-water body approach as 

requested, EPA should at least significantly revise the proposal to provide much clearer standards as to 

when a state can categorically eliminate a waterbody from Tier 2 protection. According to the 

commenters, EPA should make clear that states must not exclude from high quality water protection 

any water body that is attaining all of the uses specified in CWA section 101(a)(2). EPA agrees with 

comments that the issue of which waters must be provided Tier 2 protection needs clarification and is 

clarifying here that under section 131.12(a)(2) (a provision that has existed since 1983 and reflects EPA’s 

longstanding policy) regardless of whether a state or authorized tribe uses the water body-by-water 

body approach or parameter-by-parameter approach to identify waters for Tier 2 protection, any water 

body that is attaining all of the uses specified in CWA section 101(a)(2) must receive Tier 2 protection. 

The preamble to the final rule states this clearly: “Where water quality is better than necessary to 

support all of the uses specified in CWA section 101(a)(2), § 131.12(a)(2) requires states and authorized 

tribes to provide Tier 2 protection.” The comments also say that EPA must clarify that states must 

protect every water body as to all parameters relating to the 101(a)(2) uses the water is attaining. EPA’s 

response is in essay 7.d.iii.

Some comments stated that the parameter-by-parameter approach should be adopted by the EPA as 

the only approach compatible with the goals of the CWA. These commenters stated that the water 

body-by-water body approach is not consistent with the CWA goal because allowing new pollution that 

has not been shown to be necessary or allowing a water impaired by one pollutant to be contaminated 

by other pollutants is not consistent with the goal of maintaining and restoring the Nation’s waters. EPA 

agrees in principle with the phrase “one does not...restore waters impaired by one pollutant by allowing 

them to be contaminated by other pollutants”. However, as discussed earlier, Tier 2 protection is 

intended to protect water quality that exceeds levels necessary to support the uses specified in CWA 

section 101(a)(2). Even if a state or authorized tribe declines to provide Tier 2 protection for parameters 

for which a water has assimilative capacity in a water that is 303(d) listed as impaired for other 

parameters, it must still protect for the designated uses and criteria. Declining to provide Tier 2 

protection for any reason does not remove the responsibility of the state or authorized tribe to manage 

their water quality program to achieve the adopted designated uses and criteria. The final rule’s 

recognition that a water body–by–water body approach is acceptable is intended to facilitate 

achievement of the CWA goals of restoration and maintenance of water quality and still maintain the 

principles of cooperative federalism enshrined in the Act and in the WQS regulation as EPA’s provision 

allows a state or authorized tribe to determine the best approach for themselves that still meets the 

CWA objectives. The final rule also maintains states’ and authorized tribes’ discretion to make decisions 

about when they will allow lowering of high water quality. Therefore, EPA found that it is reasonable to 

continue to allow the use of the water body-by-water body approach.

Some commenters pointed out that EPA has mandated the parameter-by-parameter approach for 

waters covered by the Great Lakes Initiative (GLI), a fact which EPA does not dispute. Please see 

response essay 7.k. for additional discussion on the antidegradation requirements in the 40 CFR 

Part 132.

Some commenters provided hypothetical examples of water bodies with different designated uses to 

illustrate points about how the water body–by–water body approach has been used in the past. In an 

extreme example, the commenter said that a state might decide that Tier 2 applies only to waters 

containing federally listed endangered species, and that it only performs Tier 2 analyses for ammonia. In 

this case, the commenter said that a water identified for Tier 2 protection would not receive Tier 2 

review unless a discharge with new loading of ammonia would be allowed, while it would not receive 

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Tier 2 review for any other lowering of water quality. This hypothetical narrow interpretation of Tier 2 

would not be consistent with the requirements of the final rule. First, Tier 2 protection must be provided 

to waters that support all of the uses specified in CWA 101(a)(2); in the hypothetical example, a water 

could be excluded from Tier 2 even if all those uses were supported because it does not support 

federally listed endangered species. Second, limiting Tier 2 protection to only one parameter would not 

be consistent with the federal requirement at 131.12(a)(2) that “[w]here the quality of the waters 

exceeds levels necessary to support the protection and propagation of fish, shellfish, and wildlife and 

recreation in and on the water, that quality shall be maintained and protected unless...” Please see 

response essay 7.d.iii for additional discussion on conducting Tier 2 reviews after a water body has been 

identified for Tier 2 protection. 

In another example, commenters described an approach that EPA agrees has been commonly used: 

using the state’s or authorized tribe’s 303(d) list to identify waters that will not receive Tier 2 protection 

because they are impaired for one or more parameters according to the list. EPA agrees that this 

approach is problematic, because waters may be 303(d) listed due to impairments of non-101(a)(2) uses 

while waters that are not supporting the uses specified in CWA section 101(a)(2) may not be 303(d) 

listed because the uses reflect subcategories of the uses specified in CWA section 101(a)(2) instead. EPA 

agrees that a further problem with using the 303(d) list as the sole basis for deciding whether waters 

receive Tier 2 protection is that a state or authorized tribe might identify waters as not receiving Tier 2 

protection for the sole reason that one of the 101(a)(2) uses is impaired due to a single (or a small group 

of) pollutants (e.g., mercury) while the waters are still very high quality with respect to other parameters 

and other uses. Commenters provided a specific example of a state water that was impaired by mercury 

and not classified by the state for Tier 2 protection, while the state’s tourist brochures promoted the 

lake as one of the best fisheries and recreational areas in the country. While EPA does not comment on 

the specifics of the water body in the example, and does view decisions about Tier 2 protection as 

ultimately up to states and authorized tribes, the final rule requires a more holistic examination of a 

water’s worthiness for Tier 2 protection and transparency for the public than just whether it is 303(d)

listings. High water quality is a public good, and the public must be informed about decisions such as a 

decision to not provide Tier 2 protection to a water that is a major tourism and recreational resource.

EPA’s final rule makes clear that the approach described would not be consistent with the CWA or the 

regulations if the decision was made after the effective date of today’s rule and that states and 

authorized tribes must involve the public when deciding which waters receive Tier 2 protection versus 

not when implementing a water body–by-water body approach.

Some commenters objected to the proposed rule’s limitation to the water body-by-water body 

approach because it only explicitly prohibited one method for excluding waters from Tier 2 protection 

without providing direction or requirements for how the water body approach should be applied. 

Similar to the proposed rule, the final rule provides a prohibition on one specific way of using the water 

body approach that is of specific concern to EPA. As explained in the final preamble, this was intended 

to preserve state and authorized tribal flexibility while prohibiting the most commonly expressed 

concern with the water body–by–water body approach. The final rule prohibits states and authorized 

tribes from excluding waters from Tier 2 protection solely because “water quality does not exceed levels 

necessary to support all of the uses specified in section 101(a)(2) of the Act.” This means that a state or 

authorized tribe generally could not exclude a water from Tier 2 protection based on the impairment of 

one parameter unless that parameter affected all the uses specified in CWA section 101(a)(2). This 

resolves the concern that many commenters expressed that a state or authorized tribe could exclude a 

water from Tier 2 protection just because it is impaired for mercury when it is otherwise pristine. The 

preamble to the final rule explains that if a state or authorized tribe is going to use 303(d) listings as part 

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of its decision-making process, they must also consider other factors rooted in the CWA (e.g., value of 

the water for recreation). Arbitrary factors such as the name of the water body would not be factors 

consistent with the Act. The preamble to the final rule articulates more information on EPA’s 

expectations. Commenters also expressed concern that the rule would allow states and authorized 

tribes to continue to follow divergent standards for identifying high quality waters. EPA’s regulations are 

not intended to provide a one size fits all solution. As long as states and authorized tribes implement the 

water body-by-water body approach consistent with the final rule, states and authorized tribes and their 

antidegradation implementation methods will be consistent with the CWA. It is acceptable and expected 

that even within the bounds of the Act and the regulations, there will be some variability in how states 

and authorized tribes implement antidegradation requirements as there is variability in state and 

authorized tribal waters, stressors, processes and administrative requirements, but consistency with the 

CWA is required. 

EPA confirms that commenters are correct in concluding that EPA’s intent in the proposal was to 

articulate that states and authorized tribes must apply Tier 2 protection to at least the waters that meet 

all of the uses specified in CWA 101(a)(2). Commenters stated that EPA’s intention was also that states 

and authorized tribes must, in addition, provide Tier 2 protection to at least some waters that do not 

meet all these uses (e.g., a water that supports aquatic life uses but does not support recreation uses.) 

EPA agrees that this was the intention of the proposal. The final rule does not explicitly require that Tier 

2 protection must be provided to all of those waters, but is clear that while states and authorized tribes 

have discretion any such decision must be made consistent with the final rule at 131.12. Commenters 

stated that even interpreting the rule in this manner, guidance is inadequate to direct further action.

EPA has provided initial guidance in the preamble to the final rule, and will consider providing additional 

guidance in the future.

EPA disagrees that to solve the problem of states and authorized tribes not adequately implementing 

Tier 2, EPA should require use of the parameter-by-parameter approach, just the way the parameter-byparameter approach is used to identify waters that are impaired for 303(d) lists. Commenters said that it 

is does not make sense to create one set of approaches and assumptions for one purpose and an 

entirely different set of approaches and assumptions for the other side of the regulatory program. EPA 

disagrees with this characterization. For one, although 303(d) lists are generally based on chemical 

parameters (e.g., a water is listed as impaired with respect to methylmercury), this is not universally the 

case. Waters can be listed for reasons that are not parameters, for example “aquatic life,” or “unknown 

cause.” Secondly, while EPA agrees that the parameter-by-parameter approach is consistent with the 

CWA and an appropriate way to identify waters for Tier 2 protection, the water body-by-water body 

approach as required by the final rule, will also be consistent with the CWA as detailed in this essay, the 

final rule preamble, and throughout the comment response document. Finally, each regulatory program 

serves a different function in implementing the CWA. As such, it is reasonable that there may be 

different approaches and assumptions to implement each program.

EPA did not propose a definition of the term “lowering” in the context of Tier 2 review, thus such 

comments requesting a definition of the term are outside the scope of this rulemaking. EPA will consider 

providing future guidance on this term in the future.

Commenters pointed to a specific example of a state that does not conform to the description of how 

states and authorized tribes “typically” identify waters on a water body-by-water body basis in EPA’s 

proposal preamble, challenging EPA’s assumptions about inherent protections in the water body-bywater body approach. Commenters gave the example of a state that does not identify high quality 

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waters in advance of a proposed lowering of water quality, and that does not weigh a variety of factors 

to classify a water’s “overall quality.” EPA’s proposal was intended to articulate “typical” approaches for 

purposes of introducing the water body–by–waterbody approach and not to imply a judgement on 

atypical approaches. To the extent to which such atypical approaches are consistent with the 

requirements in the final rule, no changes would be needed following publication of the final rule. EPA 

will work with states and authorized tribes after the rule is published to determine whether and what 

revisions are necessary to state/authorized tribal antidegradation programs in order to be consistent 

with the revised regulations.

Commenters objected to EPA’s use of the word “may” in the following statement in the preamble to the 

proposal: “...it is currently possible for high quality waters to be identified on a water body-by-water 

body basis in a manner that the EPA believes may be contrary to the intent of the antidegradation 

provisions. In some cases, states or authorized tribes have implemented antidegradation such that, 

where a water body is listed on the CWA section 303(d) list based on one or more parameters affecting 

only one of the CWA 101(a)(2) uses, the state or authorized tribe automatically considers the water no 

longer high quality.” EPA agrees that the word “may” there indicated equivocation, when EPA’s view is 

that such a use of the water body-by-water body approach in fact would be contrary to the intent of the 

antidegradation provisions. EPA’s final rule makes clear that the use of the water body–by–water body

approach in this manner is not consistent with the Act and thus prohibited by the regulations.

Commenters objected to EPA’s proposal to not require states and authorized tribes to adopt their 

implementation methods as legally binding, while EPA claimed that the proposal would advance water 

quality protection. Commenters said that the two positions are inconsistent because the proposal would 

place a specific state’s Tier 2 approach (which they asserted to be “contrary” to the intent of the 

antidegradation regulation) outside the realm of EPA authority to reject it. While the proposal placed 

the requirements for the water body-by-water body approach in the section about implementation 

methods (which can be binding or non-binding,) the final rule requirements for the water body-by-water 

body approach are now in section 131.12(a). States’ and authorized tribes’ legally binding 

antidegradation requirements must be consistent with the new requirements for identification of 

waters for Tier 2 protection and are subject to EPA review and approval or disapproval. For more 

information, please see response essay 7.g.iii, section J.

Commenters were concerned that EPA’s proposal to allow identification of waters for Tier 2 protection 

on a water body-by-water body basis with some limitations would be too complicated, leading to states 

and authorized tribes wasting time and resources in unnecessary decision-making and considering 

holistic water quality of all of their waters, when they already face limited resources. EPA recognizes 

that states and authorized tribes have hard choices to make with regard to managing resources. The 

final rule provides discretion to states and authorized tribes so that if they choose to use a water bodyby-water body approach in order to manage their resources, they will do so consistent with the CWA 

and the WQS regulation. Using a water body-by-water body approach is not necessarily onerous, as 

states and authorized tribes can choose to identify waters as Tier 2 by default (which some states have 

done in the past.) If a state or authorized tribe finds that the water body-by-water body approach is 

indeed too onerous, they can choose a parameter-by-parameter approach.

Commenters questioned whether EPA has the resources to oversee this process, specifically oversee the 

reasons that states and authorized tribes will use to avoid being deemed as having “solely” excluded 

waters from Tier 2 protection contrary to the rule. WQS are not independently enforceable, but are 

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enforced through implementing programs such as NPDES permits. EPA’s resources for oversight of 

implementing programs as such comments are outside the scope of this rulemaking. 

C. Opposition to Proposal Because It Is Too Prescriptive

Some commenters pointed to a resolution of the Environmental Council of the States that EPA should 

minimize the use of interim guidance and draft policy and requiring Regional Administrators to require 

compliance with such policies. Comments regarding past practice of EPA Regional Administrators are out 

of scope of this rulemaking. The changes to the regulations will provide a new framework for future 

practices. Commenters said that the ECOS resolution did not merit EPA codifying former guidance as 

regulatory requirements. EPA disagrees. One way to reduce the use of guidance in making decisions, as 

the ECOS resolution requested, is to create regulatory provisions, which is what EPA has done in the 

final rule. EPA does not claim that the ECOS resolution provided authority for EPA to propose revisions 

to the WQS regulation. EPA discusses its authority to promulgate revisions in the preamble to the 

proposal and the final rule and in the response to comments document. 

Some commenters said that guidance should be recommendations from EPA, rather than an exertion of 

“one size fits all” authority over state and authorized tribal programs operating under unique, localized 

conditions. EPA agrees that guidance and policy are recommendations to states and authorized tribes 

and do not pose binding, “one size fits all” requirements. Federal rules, like the final rule, however, 

contain binding requirements nationwide. Commenters preferred EPA should leave states flexibility 

intended under the Act to identify high quality waters as appropriate for their local conditions. The final 

rule provides a binding framework of requirements to ensure that antidegradation programs are 

implemented consistent with the Act. However, rather than creating a “one size fits all” antidegradation 

program EPA leaves considerable discretion to states and authorized tribes to tailor their programs to 

local conditions. This is because states and authorized tribes have the relevant expertise to adapt their 

programs to most appropriately protect waters with site-specific conditions and to most efficiently 

operate under their own regulatory and management structures. 

EPA disagrees with the characterization made by commenters that the proposal would prohibit a water 

body from being excluded from Tier 2 protection because not all uses are attained. The final rule is clear 

that states and authorized tribes are prohibited from excluding a water from Tier 2 protection solely 

because water quality does not exceed levels necessary to support all of the uses specified in section 

101(a)(2) of the Act. States and authorized tribes may use 303(d) listings as one of the factors in their 

consideration, but not the only factor. See the discussion in the preamble and elsewhere in the 

comment response document for additional factors states and authorized tribes should consider.

Comments stated that EPA’s proposed limitation on the water body-by-water body approach (that 

waters not be excluded solely because not all of the uses specified in CWA 101(a)(2) are attained) 

implies that EPA would evaluate and review high quality waters on a parameter-by-parameter basis 

regardless of the State’s determination and identification of high quality waters. EPA does not and will 

not “evaluate and review high quality waters on a parameter-by-parameter basis” as the commenters 

say, because states and authorized tribes (not EPA) have the authority to evaluate and review high 

quality waters via Tier 2 reviews. While EPA has authority under CWA 303(c) to review legally binding 

antidegradation requirements, and in some cases those include a state’s or authorized tribe’s list of 

waters identified for Tier 2 protection (or identified as not receiving Tier 2 protection), EPA does not

evaluate and review the state’s or authorized tribe’s WQS submission on a parameter-by-parameter 

basis. EPA’s basis for review and action would be based on whether the submission is consistent with 

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the federal regulation, which specifically allows for use of a water body-by-water body approach with 

some restrictions.

Some commenters said that EPA’s proposal contradicts itself by saying that high quality waters may be 

identified on a parameter-by-parameter basis or a water body-by-water body basis at the state’s 

discretion, but then places a restriction on use of the water body-by-water body method. The final rule 

does not contain the phrase “at the state’s discretion.” The phrase “at the state’s discretion” in the 

proposal referred to the state’s decision to use the parameter-by-parameter or water body approach, 

and was not intended to mean that the state had complete discretion in how it used the method chose.

States and authorized tribes do have the discretion to choose to identify high quality waters on a 

parameter-by-parameter basis or on a water body–by–water body basis. However, if choosing a water 

body–by–water body basis, it can only be implemented consistently with the CWA with a restriction in 

regulation. Thus how a state or authorized tribe uses the water body–by–water body approach is not 

completely at the discretion of the states and authorized tribes. The final rule’s wording is intended to 

prevent confusion.

EPA disagrees with commenters stating that the restriction on the water body-by-water body approach 

regarding all uses not being attained supersedes the states’ and authorized tribes’ option to identify 

waters for Tier 2 protection using a holistic approach, rendering the entire water body-by-water body 

approach as a moot option. As discussed in the preamble to the final rule, the final rule allows 

identification of waters for Tier 2 protection using a holistic approach by only prohibiting an approach 

that would exclude waters from Tier 2 protection solely because water quality does not exceed levels 

necessary to support all of the uses specified in CWA section 101(a)(2). 

EPA disagrees with commenters stating that the rule will effectively eliminate the waterbody-bywaterbody option and effectively mandate that states and authorized tribes adopt a parameter-byparameter approach. EPA also disagrees with commenters who said that the proposal indicated that 

EPA was attempting to force states and authorized tribes to use the parameter-by-parameter approach. 

EPA does not intend to force states and authorized tribes to use only the parameter-by-parameter 

approach. EPA did not finalize a rule requiring that approach. The final rule explicitly allows for use of 

the water body-by-water body approach and the restriction in the rule on the use of the water body-bywater body approach is intended to ensure that such an approach is implemented consistent with the 

CWA and to provide regulatory language that states and authorized tribes can use to guide their state 

actions. . The preamble to the final rule describes how states and authorized tribes can use a 

waterbody-by-waterbody approach in a manner consistent with the CWA but this manner is not 

equivalent to the parameter-by-parameter approach. Using a water body–by–water body approach 

consistent with the final rule still allows states to look at the overall water quality. In addition, this 

manner still leaves open the possibility for a state to determine that a water body is not deserving of 

Tier 2 protection even if certain parameters have assimilative capacity. Some commenters stated that 

imposing new obligations on states and authorized tribes using a water body-by-water body approach 

creates a new administrative preference to switch to a parameter-by-parameter approach. EPA does not 

have information to support agreement or disagreement with this position, and views this as something 

that would vary among states and authorized tribes. EPA’s rule is intended to provide states and 

authorized tribes choices in how to identify high quality waters consistent with the CWA and today’s 

rule successfully provides those choices.

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Commenters objected to restrictions proposed for the water body-by-water body approach, saying such 

restrictions are unnecessary, an undue intrusion on state and authorized tribal primacy for 

implementation, and will prevent the flexibility to implement efficiently and beneficially. They stated 

that EPA should specify that states and authorized tribes have discretion, per the Agency’s current 

policy, to use whatever mechanism they choose to identify high quality waters on a water body-bywater body basis. EPA disagrees. EPA described the reasons for adding restrictions to the water body-bywater body approach in the preamble to the proposal. The final rule allows states and authorized tribes 

to use the parameter-by-parameter method or to use the water body method with some specified 

limitations so that it will be used consistently with the CWA. The final rule’s recognition that a water 

body–by–water body approach is acceptable is intended to facilitate achievement of the CWA goals of 

restoration and maintenance of water quality and still maintain the principles of cooperative federalism 

enshrined in the Act and in the WQS regulation as EPA’s provision allows a state or authorized tribe to 

determine the best approach for themselves that still meets the CWA objectives. It does not intrude on 

state or authorized tribal primacy, as it still offers broad discretion in implementation, which will allow 

for efficient and beneficial implementation.

Commenters stated that the proposed changes would increase the burden of states and authorized 

tribes to do Tier 2 reviews on waters that have impairments, would negate any resource advantage of 

the water body approach, would increase permit renewal costs, and would tax states’ and authorized 

tribes’ limited resources. EPA’s economic analysis (EA) takes into account any increase in cost or burden 

of this rule. For additional discussion on the EA of this rule, see essay 12.b.

Commenters suggested that the final rule text specify that the water body-by-water body approach may 

be used at the state’s discretion, taking into consideration appropriate chemical, biological, and physical 

characteristics. EPA agrees in principle that states and authorized tribes should consider chemical, 

biological and physical characteristics of a water body when determining whether to provide Tier 2 

protection. However, EPA’s view is that this wording would not provide any more limitation to the water 

body-by-water body method than there has been in the past. The word “appropriate” would be 

subjective, and a state or authorized tribe could argue anything as an “appropriate” consideration. 

Therefore, EPA’s final rule provides this same flexibility but clearly prohibits implementation of the 

water body–by–water body method that is contrary to the CWA and EPA regulations.

Commenters provided state-specific examples of states that use the water body-by-water body 

approach, stating that the approach has been approved by EPA, is defensible, has been an effective 

regulatory tool for years, and that new restrictions on the approach would be unnecessary and 

inappropriate. Commenters stated that the states’ successful antidegradation programs take a holistic 

view of water quality conditions in determining which water bodies are considered truly “high quality” 

to be protected by Tier 2. While state antidegradation policies and implementation methods may have 

been in compliance with the previous federal regulations, EPA has found that today’s final rule is 

reasonable and necessary to provide consistency and transparency. The final rule still requires a holistic 

approach to identifying high quality waters and still allows for the states and authorized tribes to 

determine which waters that will and which waters will not be provided Tier 2 protection. State and 

authorized tribal programs that use a robust, holistic approach and ensure that their decisions are

subject to public involvement would be consistent with the final rule.

EPA disagrees with commenters stating that EPA “seems to assert that States are not implementing 

antidegradation.” The preamble to the proposal stated that “...EPA indicated in its 1998 ANPRM that ‘on 

a national scale, antidegradation is not being used as effectively as it could be,’ a concern that continues 

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today and is echoed by stakeholders who have identified antidegradation as an underused component 

of water quality protection.” EPA’s statements express that antidegradation is underutilized, not that it 

is not being implemented. EPA recognizes that antidegradation implementation varies throughout the 

country, and it is likely that some jurisdictions implement more thoroughly than others. Commenters 

further stated that in a specific state, the requirements of Tier 2 are so onerous that they are avoided, 

and that permits retain old effluent limits rather than risk increasing loading and incurring the Tier 2 

review process. EPA understands that avoiding Tier 2 review by prohibiting discharges that degrade high 

water quality is one tactic that can be used to manage resources and still protect high water quality. 

However, Tier 2 review need not be onerous so as to avoid proper and efficient management of high 

water quality. For example, EPA describes in the preamble to the final rule that alternatives analysis 

should document a level of detail that reflects the significance and magnitude of the particular 

circumstances encountered. A proposed degradation that is less significant could have a less onerous 

analysis than one that would degrade more. Furthermore, although conducting Tier 2 review requires 

some state and authorized tribal resources, as many commenters point out, components of a Tier 2 

review (particularly the analysis of alternatives) are commonly conducted by dischargers seeking 

authorization. Finally, even though resources are expended in conducting Tier 2 reviews, implementing

an antidegradation program to prevent the degradation of a water body may be more cost-effective and 

efficient than long-term restoration efforts. In addition, maintaining a water body in its initial high 

quality condition helps ensure the preservation of unique attributes that may ultimately be impossible 

to fully restore in a number of situations. EPA disagrees with comments stating that while the cost of 

permitting increases when antidegradation-based effluent limits must be calculated, nothing is 

accomplished by doing so, and antidegradation is a misallocation of resources. For the reasons cited in 

this paragraph and in the preambles to the proposed rule and the final rule, avoiding any unnecessary 

degradation of water quality is a valuable allocation of resources and not a misallocation of resources.

Effluent limits that reflect Tier 2 protection often protect more high water quality than would have been 

protected otherwise. This outcome supports CWA goals and protects a valuable public and community 

resource and thus cannot be characterized as accomplishing nothing.

Some commenters stated that restrictions on the states and authorized tribes in terms of the water 

body-by-water body approach would reflect the current practices of the states. Commenters stated that 

many states would not consider waters ineligible for Tier 2 protection if recreational criteria are 

exceeded while aquatic life resources were unimpaired, or if impairments for mercury, PCBs, or other 

legacy pollutants led to a ban on human consumption while the viability of the wildlife itself was

unimpaired. EPA agrees that considering waters eligible for Tier 2 protection if they are meeting some 

uses specified in CWA 101(a)(2) but not others is consistent with the final rule.

Commenters recommended that EPA change the regulatory text to read: “must not exclude any water 

body from high quality water protection solely because not all of the individual elements of the uses 

specified in CWA section 101(a)(2) are attained,” because “uses specified in CWA 101(a)(2)” is general 

and does not distinguish between uses involving human consumption, predator consumption, sport 

fishing or other harvesting, and the natural viability of wildlife for its own purposes. EPA disagrees with 

this recommendation, and did not finalize such text. Such text appears to be intended to reflect the 

variations in how states and authorized tribes articulate their own designated uses. Some states and 

authorized tribes, for example, protect the “fish” component of CWA section 101(a)(2) by adopting 

multiple and distinct uses such as cold water aquatic life use, warm water aquatic life use, salmon 

fishery, trout waters, etc. EPA chose to articulate the requirement using the words of the CWA because 

regardless of how states and authorized tribes adopt their own WQS, the uses specified in CWA section 

101(a)(2) are a universal goal and is thus a universal baseline for determining when water quality 

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exceeds levels necessary to support those uses. In addition, the suggested text would imply that 

although a water could not be excluded from Tier 2 protection solely because not all of the individual 

elements of the uses specified in CWA 101(a)(2) are attained, the water could still potentially be 

excluded solely because one of the CWA 101(a)(2) uses more generally is not attained. This was not 

EPA’s intention, as explained in the preambles to the proposed and final rules.

Commenters provided feedback on the examples EPA had provided in the preamble to the proposal, 

stating that even if an aquatic life use is not fully supported, there could be legitimate concern for 

negative synergistic effects of different pollutants that have individual, applicable criteria. EPA agrees, 

and this is one reason that the final rule requires states and authorized tribes to consider more than one 

factor (specifically more than just whether the water is impaired for one or more 101(a)(2) uses) when 

deciding whether to provide Tier 2 protection to waters that are not supporting all of the CWA 101(a)(2) 

uses. Synergistic effects may be a reason to provide the water with Tier 2 protection. The commenters 

stated that in allowing an increased and/or new discharge of these pollutants without Tier 2 review, 

states and authorized tribes could also require whole effluent toxicity (WET) testing and where 

appropriate, in-stream biological sampling. It is true that permitting authorities have discretion to 

require monitoring, testing, and other conditions in association with a permit issuance or renewal. How 

permitting authorities choose to write NPDES permits is outside the scope of the WQS regulation.

EPA agrees with comments that the incorporation of the 303(d) list into the States’ decision-making 

about which waters to provide Tier 2 protection is within the States’ and authorized tribes’ authority. 

The final rule allows for this, provided the fact that a water is 303(d) listed and therefore is not 

supporting all of the uses specified in CWA 101(a)(2) is not the sole justification for excluding a water 

from Tier 2 protection. 

EPA disagrees with comments that water bodies that are 303(d) listed as impaired would not be 

appropriately labeled as high quality waters, so those waters should not be provided Tier 2 protection.

EPA’s view is that waters that are listed on a 303(d) list as impaired for one or some parameters should 

still be able to receive Tier 2 protection for parameters for which they have high water quality. This 

would be consistent with the intent of the CWA, since many water bodies impaired due to parameters 

such as mercury and PCBs may otherwise be high quality and worthy of Tier 2 protection. Commenters 

stated that providing Tier 2 to such waters is not consistent with some states’ and authorized tribes’ 

previous practice and would inappropriately divert limited state and authorized tribal resources away 

from protecting waters that are “truly high quality.” Under the final rule, states and authorized tribes 

still have the flexibility to be able to exclude such waters from Tier 2 on a water body-by-water body 

basis as a way of managing their limited resources, provided they do so consistent with the final rule. 

EPA’s regulations are intended to strengthen the antidegradation program and is not obligated to 

establish regulations consistent with existing state/authorized tribal practice. EPA developed these 

regulations based on its past experience with state/authorized tribal antidegradation programs and 

input from a wide spectrum of stakeholders. Some commenters stated that not providing impaired 

waters with Tier 2 protection would be consistent with the overarching purposes of the CWA while 

maintaining state and authorized tribal flexibility in developing antidegradation policies to address sitespecific considerations. EPA agrees that as long as impaired waters are excluded from Tier 2 protection 

only after a holistic evaluation that identifies another rationale to support the decision and a public 

process, such decisions will be consistent with the overarching purposes of the CWA. However, EPA 

continues to disagree that denying a water impaired from one parameter a tier 2 review for other 

parameters for no other reason is consistent with the CWA.

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EPA disagrees with comments stating that CWA 303(d)(4)(B) hints that the consideration of 

antidegradation applies to waters whose quality exceeds that necessary to support their designated 

uses and thus the converse would be Tier 2 considerations are prohibited for waters whose quality is 

cause for listing as unattained. The final rule requires Tier 2 protection where water quality exceeds the 

levels necessary to support all of the uses specified in CWA 101(a)(2), but that in any other case, states 

and authorized tribes have choices about whether to provide Tier 2 protection or not. EPA disagrees 

that the text of CWA 303(d)(4)(B) means that antidegradation applies only to waters whose water 

quality exceeds that necessary to support all of the designated uses. EPA’s statutory authority for the 

final regulation at section 131.12(a)(i) is outlined in this final rule preamble, proposal preamble, and 

elsewhere in this comment response document. EPA’s authority for this rulemaking is found at Sections 

303, 101 and 501 of the Act. Under this authority, EPA promulgated Section 131.12(a)(2) in 1983 (which 

retained, with some changes, the antidegradation policy regulations of 40 CFR 130.17(e) which were 

promulgated in 1975). Today’s rulemaking is established under these authorities. EPA is promulgating 

necessary regulations to carry out the functions under the Act. Section 131.12(a)(i) is consistent with the 

Act and longstanding EPA policy. Consistent with Section 101(a)(2), 303, and 501, the rule makes clear 

that Tier 2 applies to water quality better than necessary to support CWA 101(a)(2) uses, not simply 

whatever uses are designated for the waters.

EPA disagrees with comments stating that the proposal implied that there must be a second layer of 

assessment for waters that may not meet a specific use and subsequently are listed on the state’s 

303(d) list, yet may have a quality of water that exceeds the level necessary to support other uses. 

Commenters stated that this additional review is not necessary and that states and authorized tribes are 

already spending a lot of time assessing waters for 303(d) lists. The final rule does not require a second 

layer of assessment, but the rule does allow for a second layer, depending on the state’s choice of water 

body-by-water body approach or parameter-by-parameter approach and state processes. It is true that 

where states and authorized tribes identify waters for Tier 2 protection on a water body-by-water body 

basis, if they are going to exclude waters from Tier 2 protection, they must do a holistic assessment to 

determine which waters will and will not receive Tier 2 protection. In other words, if states and 

authorized tribes wish to use a water body–by–water body approach rather than a parameter – by – 

parameter approach, then it stands that the state or authorized tribe must make high quality water 

decisions on the basis of an overall assessment of the water body and not solely based on individual 

303(d) listings. However, a water body–by–water body approach is not the only way to identify waters 

for Tier 2 protection States and authorized tribes can identify all of their waters for Tier 2 protection 

without doing an additional assessment or they can also identify their waters for Tier 2 protection on a 

parameter-by-parameter basis instead where individual 303(d) listings based on the particular 

parameter in question can be the sole source of information. 

EPA disagrees with comments suggesting that the final rule specifically allow discretion to use an 

alternate approach that would identify water quality for Tier 2 protection on a “use-by-use” basis, rather 

than water body-by-water body. According to the commenters, under such an approach, a water that 

does not support CWA 101(a)(2) aquatic life uses but supports CWA 101(a)(2) recreational uses would 

receive Tier 2 protection for the recreation uses but not the aquatic life uses. For EPA’s response to 

comments regarding which parameters receive Tier 2 review after a water body is identified for Tier 2 

protection, please see response essay 7.d.i.

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Other commenters described identifying waters for Tier 2 protection on a different type of “designated 

use” basis, whereby a water body with water quality better than necessary to support one entire use 

specified in CWA section 101(a)(2) (e.g., aquatic life) would be considered a Tier 2 water (for all uses.) 

EPA would view this type of approach as consistent with the final rule.

EPA disagrees with comments stating that if a water body is meeting just one water quality criterion that 

supports a CWA 101(a)(2) use, but not meeting any other water quality criteria, a state or authorized 

tribe nonetheless may be compelled by EPA to identify the waterbody as high quality, and if the state or 

authorized tribe fails to do so, then EPA may disapprove the state’s action under the auspices of 

reviewing the state’s standards submittal. The final rule does not require states and authorized tribes to 

provide Tier 2 protection to waters meeting just one criterion that supports a CWA 101(a)(2) use. In such 

situations, it requires the state or authorized tribe to consider a holistic assessment before excluding a 

waterbody from Tier 2 protection and subject the decisions to public involvement. In addition, as 

discussed earlier in this essay and in other essays, EPA’s authority under section 303(c) to act on 

standards is limited to those that are new or revised. EPA will only have an opportunity to act on a 

state’s or authorized tribe’s identification of high quality waters if it is a new or revised WQS. 

EPA disagrees with comments that EPA did not identify a compelling reason to restrict use of the water 

body-by-water body approach. Commenters did not explain why EPA’s reasons were not compelling and 

EPA has repeated its reasons for the regulatory changes in this response essay. EPA disagrees with 

comments that the proposal expands EPA’s authority without authorization. The proposal and final rule 

do not expand EPA’s authority. The final rule is consistent with the CWA and EPA’s longstanding policies. 

The final rule enhances protection of high quality waters and promotes consistency in implementation 

of the regulations and increases transparency and opportunity for public involvement. The rule 

preserves states’ and authorized tribes’ decision-making flexibility. EPA explained its reasoning and its 

authority in the preamble to the proposal and the preamble to the final rule (and elsewhere in the 

response to comments) and the final rule reflects EPA’s existing authority to establish regulations that 

serve the purposes of the CWA. 

EPA disagrees with comments stating the proposed changes to the regulation regarding identification of 

high quality waters (and analysis of alternatives) are overly prescriptive and would reduce flexibility of 

states, because the CWA specifically delegates to the states the discretion in weighing the “use and 

values” of various state waters for alternative purposes. EPA notes that CWA 303(c)(2)(A): “Whenever 

the State revises or adopts a new standard, such revised or new standard shall be submitted to the 

Administrator. Such revised or new water quality standard shall consist of the designated uses of the 

navigable waters involved and the water quality criteria for such waters based upon such uses. Such 

standards shall be such as to protect the public health or welfare, enhance the quality of water and 

serve the purposes of this Act. Such standards shall be established taking into consideration their use 

and value for public water supplies, propagation of fish and wildlife, recreational purposes, and also 

taking into consideration their use and value for navigation.” The regulation does not prohibit 

consideration of “value” and the preamble to the final rule discusses how public value can be considered 

when identifying high quality waters.

Commenters objected to the proposed changes because they would impose new obligations on some 

states and authorized tribes using water body-by-water body approaches, potentially subjecting more 

waters to Tier 2 review, and that EPA had incorrectly characterized the changes as clarification of 

existing requirements. EPA agrees that the final rule imposes new obligations, although EPA points out 

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that many of the changes indeed represent clarifications of existing policy. EPA appropriately requested 

comment on all of the proposed changes. The title of rule does not substantively alter its content.

Commenters stated that if a state or authorized tribe improperly designates a waterbody (i.e., as not 

receiving Tier 2 protection) and thus denies antidegradation review in a particular permit proceeding 

involving a waterbody that should be, but is not, listed as high quality, then EPA (along with any 

interested third party) would have immediate recourse to challenge that aspect of the state’s permit 

decision. EPA agrees that EPA has oversight authority over permits in many cases (e.g., NPDES), and can 

step in if a state or authorized tribe did not appropriately carry out Tier 2 review where it is warranted. 

In the NPDES example, likewise, the public has the opportunity to comment and challenge that aspect of 

a proposed permit. The commenters said that ensuring proper classifications, as applied, seems to be a 

better and more direct option than what EPA proposes because it respects state discretion in listing 

water bodies, while at the same time protecting against error at the point when those listings are in fact 

applied. EPA agrees that proper classification in the first place is the most publicly transparent approach, 

however EPA does not view this as opposing what EPA had proposed. The final rule requires that states 

and authorized tribes adopt legally binding requirements that are consistent with section 131.12(a), 

including the regulations governing use of a water body–by–water body approach, and EPA and the 

public have a chance to view and be involved in state and authorized tribal decisions about whether a 

water receives Tier 2 protection. Whether this involvement happens during a WQS rulemaking, a 

permitting or licensing process, or all of the above, depends on the state’s or authorized tribe’s specific 

procedures.

EPA disagrees with comments suggesting that if EPA finalizes changes to the rule, it should clarify that 

previously approved state and authorized tribal antidegradation policies and methods remain in effect 

and do not need to be amended. The rulemaking process is established recognizing that regulations may 

need to change in order to better meet the objectives of the CWA as new environmental challenges 

arise and new science is developed. EPA’s preamble to the proposed rule and final rule explain that 

federal antidegradation requirements were not fully successful in ensuring that antidegradation is 

implemented consistent with the CWA. EPA is ready to assist any state or authorized tribe in evaluating 

their currently applicable antidegradation requirements to determine whether and what revisions are 

necessary to comply with the new requirements. EPA understands that any potential revisions may take 

time. Thus, the preamble to the final rule explains “EPA’s expectation is that, where a new or revised 

requirement necessitates a change to state or authorized tribal WQS, such revisions will occur within the 

next triennial review that the state or authorized tribe initiates after publication of the rule.” 

EPA disagrees with commenters’ assertion that the proposal would expand the definition of “high 

quality” water well beyond its historical application, which focused on those waters where water quality 

exceeds levels necessary to support propagation of fish, shellfish, and wildlife and recreation in and on 

the water. The final rule does not substantially change the definition of what constitutes high quality 

waters in 131.12(a)(2) but rather puts restrictions on one approach so that it remains consistent with 

the existing definition of high quality. As in the past, states and authorized tribes identify their own 

waters for Tier 2 protection, which can be broader (parameter-by-parameter) or narrower (water bodyby-water body).

EPA disagrees with commenters’ assertion that the proposed changes to antidegradation would 

“subdivide uses finer and finer,” multiplying the resources needed to deal with them. Nothing in the 

final rule provisions for antidegradation requires subdivision of designated uses. Tiers of antidegradation 

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protection are distinct from designated uses. The final rule does not create any more tiers or require 

states and authorized tribes to create any more tiers of antidegradation protection. 

EPA disagrees with comments arguing that the proposal would lead to litigation due to vagueness. 

Comments stated that the proposal for identification of high quality waters was vague and ambiguous, 

and would therefore lead to litigation. Commenters pointed to concerns that legal challenges could 

come up regarding how it is to be judged whether a water is excluded “solely because” water quality is 

not exceeding levels necessary to support all of the uses specified in CWA 101(a)(2), how “solely” is 

defined, what it means as far as the obligations on states and authorized tribes, and what “overall 

holistic assessment” means. Commenters stated that EPA should clarify. EPA recognizes that regulatory 

provisions that do not provide a great deal of detail can lead to challenges for permit writers or others 

implementing the standards and for courts reviewing actions related to the standards. State and 

authorized tribal decisions on whether or not to apply Tier 2 protection to waters on a water body-bywater body basis have been subject to legal challenge in the past, when EPA provided no limitations to 

how the method could be used, and a variety of interpretations existed. The final regulation provides 

more structure to the requirement to identify waters for Tier 2 protection; EPA finds that the rule is not

vague or unreasonably subjective. Short of making the regulation completely prescriptive, there is no 

way to prevent litigation over what exactly is required by the regulation in the future. The final rule 

strikes a balance between providing some boundaries and clarity on what the regulation means, while 

avoiding overly prescriptive dictates. EPA’s view is that the level of detail in the final rule is appropriate 

for the regulation, while guidance is more appropriate for describing the specifics of how states and 

authorized tribes could identify waters for Tier 2 protection. The proposal preamble and preamble to 

the final rule provide important interpretive information to which co-regulators and the regulated 

community can look for clarification. States and authorized tribes have the ability to reduce uncertainty 

for regulated entities in their jurisdictions by providing additional rules or guidance that complement 

but are more detailed than the federal requirements. EPA will consider these issues when developing 

subsequent guidance on antidegradation after the final rule is published.

EPA disagrees with comments saying that that the restrictions to the water body-by-water body 

approach would result in a situation where state and authorized tribal decisions are too easy to 

challenge, and that they could be forced to do endless studies. State and authorized tribal decisions on 

whether or not to apply Tier 2 protection to waters on a water body-by-water body basis have been

subject to legal challenge in the past, when EPA provided no limitations to how the method could be 

used, and a variety of interpretations existed. Commenters provided no explanation as to why adding 

conditions to the water body-by-water body approach would lead to more legal challenges than in the 

past. If a state or authorized tribe identifies waters for Tier 2 protection and waters that will not receive 

Tier 2 protection consistent with the final rule, and subjects those decisions to public involvement, it has 

appropriately followed the rule requirements. There is no reason decisions about Tier 2 protection in 

particular would lead to public involvement requiring endless studies any more than other decisions that 

are subject to public involvement.

Commenters provided no explanation for the assertion that changes to the requirements for using a 

water body-by-water body approach will force states and authorized tribes to change to the parameterby-parameter method in order to avoid litigation. EPA does acknowledge that the parameter-byparameter method is inherently more objective.

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EPA disagrees with comments that the proposal was inconsistent with state policies to encourage 

infilling and protecting green space by placing additional barriers on discharges near impaired waters. 

The final rule does not explicitly place additional barriers on discharges near impaired waters nor does it 

require states and authorized tribes to classify impaired waters as Tier 2. However, where such waters 

are in fact identified as high quality waters, this does not mean that the state or authorized tribe cannot 

also move towards infilling and protecting green space. A Tier 2 review only means that the decision 

making progress to allow any lowering and how much lowering goes through a public process. During 

the Tier 2 review, the alternatives analysis will need to consider whether there are any alternatives to 

lowering the water quality and whether the activity accommodates important economic or social 

development. After the process, the state/authorized tribe and the public may decide that such 

activities are a valuable use of the assimilative capacity.

Commenters stated that under the water body-by-water body approach, EPA’s explanation ignores that 

even if Tier 2 protection is not afforded a use because the water body is impaired for another use, that 

first use must nevertheless be fully protected, including the maintenance of the water quality criteria 

established for the protection of that use. The commenter conflates the protection of high water quality 

in a Tier 2 water with protection of a designated use (via criteria.) These are fundamentally different, 

because Tier 2 protects water quality above and beyond that necessary to support the uses specified in 

CWA section 101(a)(2), so simply protecting a designated use (for example, of aquatic life or recreation) 

and associated criteria will not provide the same protection that Tier 2 would.

Commenters did not provide explanations for assertions that the proposed changes to the identification 

of waters for Tier 2 protection would not provide environmental benefit. EPA discusses the benefits of 

providing more waters with Tier 2 protection in the preamble to the proposal and the final rule. 

Commenters objected to the proposed changes to the provision regarding identification of waters for 

Tier 2 protection with the argument that it would require a ‘one-size-fits-all’ approach when local 

conditions vary. EPA disagrees. The final rule allows states and authorized tribes to use the parameterby-parameter approach, or a water body-by-water body approach, which are fundamentally different 

approaches. Further, when using a water body–by–water body approach, EPA’s rule does not prescribe 

exactly how it is to be used, just one way that is prohibited. States and authorized tribes have discretion 

as to the factors they consider and how they weigh those factors when identifying waters for Tier 2 

protection on a water body-by-water body basis as long as they go through a public process for each 

decision. The evaluation need not be the same in every state and authorized tribe that uses a water 

body-by-water body method. It need not be the same even within a state or authorized tribe, as they 

may weigh factors differently in different waters.

EPA acknowledges that commenters provided reasons to justify why the water body-by-water body 

approach should be retained, and can be in some cases preferable to the parameter-by-parameter 

approach. EPA agrees that the water body-by-water body approach accommodates a holistic approach 

(e.g., allowing weighing the importance of various parameters, considering the value to the ecosystem) 

while the parameter-by-parameter approach does not. EPA agrees that a water body-by-water body 

approach can provide more flexibility to states and authorized tribes in terms of excluding waters from 

Tier 2 protection. EPA agrees that a water body-by-water body approach may facilitate implementation 

in states and authorized tribes because which waters are protected by Tier 2 can be identified upfront. 

EPA recognizes that commenters see drawbacks with the parameter-by-parameter approach, including 

that it is difficult to implement for general permits, can be cumbersome and can require more data and 

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parameter approach likely results in more waters receiving some degree of Tier 2 protection because it 

would cover waters that are clearly not attaining goal uses (i.e., waters which are not supporting the 

uses specified in CWA section 101(a)(2) but that possess assimilative capacity for one or more pollutant).

Commenters also stated that they favored the water body-by-water body approach because the 

parameter-by-parameter approach overlooks the larger impact of the proposed activity that would 

degrade water quality. EPA disagrees with this characterization, and commenters did not provide an 

explanation for the assertion. Under the parameter-by-parameter approach, Tier 2 protection is 

provided for all of the parameters for which the water has high quality; it does not overlook the larger 

impact of the proposed activity. Comments stated that the parameter-by-parameter approach fails to 

accommodate a holistic analysis that balances the presence of nonattainment of some parameters along 

with the better than necessary quality parameters and determines the value to the ecosystem of 

maintaining the better quality. EPA agrees that the parameter-by-parameter approach does not 

“balance” considerations of different parameters and values, but does not characterize this as a 

“failure,” since the approach clearly protects high water quality consistent with the CWA. In addition, 

states and authorized tribes may take into consideration the advantages and disadvantages of each 

approach when deciding which approach to use to identify high quality waters.

On the other hand, EPA acknowledges that commenters provided reasons to support a parameter-byparameter approach. Commenters said that since Tier 2 is a function of the water body, its existing 

water quality (relative to a given pollutant) and the proposed discharge of that given pollutant, those 

factors complicate the task of compiling a list of Tier 2 waters whose status restricts introduction of new 

or expanded pollutant loads. EPA agrees that for this reason, some states and authorized tribes may find 

a parameter-by-parameter approach more workable.

Some commenters expressed concern that certain waters may be identified as Tier 2 when available 

data to conduct an overall holistic assessment are either inadequate or a legitimate and substantial 

disagreement exists over the data (e.g., validity, what they purport to demonstrate, how they were 

obtained). EPA recognizes that any decisions made on the basis of data can be disputed; in many 

situations, permit writers and state or authorized tribal officials are faced with the prospect of making

decisions with limited data. Tier 2 provides a framework for state and authorized tribal decisions. The 

final rule sets some boundaries on that framework when identifying waters for Tier 2 protection on a 

water body-by-water body basis. Beyond those boundaries, decisions about preservation of high water 

quality rest with the states and authorized tribes, subject to public involvement. The final rule does not 

impose data requirements, but states and authorized tribes may create their own data requirements to 

make clear to the public how they will handle situations with different data limitations. EPA’s preamble 

to the final rule says that “...in instances where states and authorized tribes lack data and information 

on the water quality to make individual water body conclusions, EPA recommends that they provide all 

or a subset of their waters with Tier 2 protection, by default. Doing so will increase the probability that 

these waters will maintain a level of resiliency to future stressors.” 

EPA responds to commenters’ requests for clarification here.

Some commenters requested that the proposed language be revised to clarify that waters identified for 

Tier 2 protection on a parameter-by-parameter basis may be excluded from Tier 2 protection for those 

individual parameters that have been identified as impaired. EPA agrees that this is the case, since 

where there is no assimilative capacity for a parameter, Tier 2 protection cannot be provided. EPA did 

not change the rule to specifically clarify this because it is not a change in position or interpretation, and 

EPA is clarifying here.

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Some commenters requested clarification on whether the rule requires a “tipping point” at which 

certain waters would be considered Tier 2 for all uses, even if not all (or most) CWA 101(a)(2) uses are 

met currently. For a water body-by-water body approach, if water quality exceeds levels necessary to 

support all the uses specified in CWA 101(a)(2), Tier 2 protection must be provided. If not, states and 

authorized tribes have discretion to choose whether or not to apply Tier 2 protection, provided it is in 

accordance with the final rule. A state or authorized tribe could base a decision to exclude a water from 

Tier 2 protection on the fact that it is supporting none of the uses specified in CWA 101(a)(2), or based 

on the fact that it is impaired with respect to at least one of those uses plus other factors considered in a 

holistic evaluation (see preamble to the final rule for more information on other factors that could be 

considered.)If a water is identified for Tier 2 protection, such protection is for all parameters and all uses 

for which the water has high quality. Please see response essay 7.d.iii for additional discussion on 

conducting Tier 2 reviews.

Some commenters requested confirmation that a water impaired for one of the CWA 101(a)(2) uses 

would not be considered a high quality water, pointing to EPA’s previous actions in Kentucky, as 

discussed in Kentucky Waterways v. Johnson, 540 F.3d 466, 479 (6th Cir. 2008). The final rule 

requirement regarding identification of waters for Tier 2 protection on a water body-by-water body 

basis is different from the previous requirement, which did not limit use of the water body-by water 

body approach in any way. Under today’s rule, waters that do not support all CWA 101(a)(2) uses can be 

considered “high quality,” and protected by the Tier 2 regulations. EPA appropriately conducted notice 

and comment rulemaking to establish this interpretation in the final rule. Ky. Waterways was a 2008 

case decided under EPA’s previous regulations. Please see response essay 7.d.iii, section B for additional 

discussion regarding the change from previous policy statements and the court rulings.

Commenters expressed concern that upon finalization of the rule, states and authorized tribes would be 

required to undertake a proactive process of identifying all their high quality waters. They stated that 

the proposed rule could be misconstrued to require this, and requested clarification from EPA. EPA 

clarifies here that no such large-scale, proactive endeavor is required. The final rule does not impose a 

timeframe for when waters must be identified for Tier 2 protection. It requires that for instances where 

a state or authorized tribe uses a water body-by-water body approach to identify waters that will and 

will not receive Tier 2 protection, whenever they do so, they must involve the public in those decisions. 

Some states and authorized tribes may wish to do this as part of a large-scale proactive endeavor; 

others may wish to do it in another way. EPA also makes clear that there is no need for any proactive 

process to identify high quality waters when using a parameter–by–parameter approach as each 

decision occurs at the time a lowering is proposed.

EPA agrees with comments stating that the proposed regulatory language and proposal preamble 

seemed to conflate water quality sufficient to meet CWA 101(a)(2) uses (protection and propagation of 

fish, shellfish, and wildlife, and recreation in and on the water) with water quality where the quality of 

the waters exceeds (or is better than) that necessary to support the uses specified in CWA section 

101(a)(2). EPA agrees that, per 131.12(a)(2), Tier 2 protection is for the increment of water quality that 

is better than that necessary to support the uses specified in CWA section 101(a)(2). Water quality that 

just meets the level necessary to support CWA 101(a)(2) uses would not have additional assimilative 

capacity for which to provide Tier 2 protection. The proposal language regarding guidelines for the use 

of the water body-by-water body approach stated that states and authorized tribes “must not exclude 

any water body from high quality water protection solely because not all of the uses specified in CWA 

101(a)(2) are attained.” EPA recognizes that the proposal language on use attainment could be 

misleading, and reworded the language in the final rule to read that states and authorized tribes “shall 

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not exclude a water body from the protections described in (a)(2) of this section solely because the 

water quality does not exceed levels necessary to support all of the uses specified in section 101(a)(2) of 

the Act.” EPA disagrees with commenters, however, that the rule has always focused on “water quality 

better than necessary to attain the highest uses, in other words, truly pristine waters.” First, the uses 

specified in CWA section 101(a)(2) uses are not necessarily the “highest uses,” depending on how a 

particular state or authorized tribe designates uses. A state or authorized tribe may have use 

designations that are more stringent than use designations protecting the uses specified in CWA 

101(a)(2). Secondly, the existence of high water quality better than necessary to support the uses 

specified in CWA section 101(a)(2) does not mean that a water is “truly pristine.” Many waters of the 

U.S. are not “truly pristine” due to pollution, but still have assimilative capacity that could be protected 

by Tier 2 of antidegradation. EPA further disagrees with the comment that it is inherently incompatible 

with the notion that Tier 2 waters deserve protection because they have the very highest water quality 

to say at the same time that the state has to classify a water as Tier 2 even where the water is impaired 

for one or more uses. First, 131.12(a)(2) does not specify that Tier 2 protection is for the “very highest 

water quality,” it is simply for water quality that is better than necessary to support CWA 101(a)(2) 

levels. Second, the proposed rule did not and the final rule does not require waters to be classified as 

Tier 2 if they are impaired for one or more uses. As discussed throughout this essay and final rule 

preamble whether or not to protect a water identified as impaired for one or more uses or parameters 

depends upon the holistic assessment and the public process. EPA’s regulation only prohibits one way of 

implementing the water body–by–water body approach.

Some commenters requested that the final preamble include language clarifying that the rule does not 

preclude a state’s discretion to leave a waterbody off the Tier 2 list if one or more of its uses is not met. 

EPA agrees that under the final rule states and authorized tribes do have this discretion, provided they 

do so consistent with the requirements of the final rule.

Some commenters requested clarification on whether EPA requires Tier 2 protection be provided for 

parameters associated with all of the CWA 101(a)(2) uses, or whether it is just for the use (or uses) being 

supported. Please see response essay 7.d.iii for EPA’s response. 

Some commenters were concerned that the proposal language prohibiting waters being excluded from 

Tier 2 under the water body-by-water body approach solely because not all of the uses specified in CWA 

section 101(a)(2) are “attained” could be interpreted in a variety of ways, particularly since EPA did not 

define “attain.” EPA agrees with the commenters that the proposal focused on situations where states 

and authorized tribes have refused to classify waters for Tier 2 protection because the waters are 303(d) 

listed as impaired for one or more parameters. However, the commenters stated that the proposal 

could be read to preclude states and authorized tribes from identifying as Tier 1 (that is, declining to 

provide Tier 2 protection) to waters that have not been classified with designated uses reflecting all of 

the uses specified in CWA 101(a)(2) (including support of aquatic life, support of wildlife, consumption 

of aquatic life, recreation). The commenters provided examples of ephemeral waters that a state has 

classified as Tier 1, and which have designated uses reflecting aquatic life, wildlife, and limited 

recreation, but not fish consumption because they cannot support a fish population. The commenters 

were concerned that EPA’s proposed rule would require that the absence of a fish consumption use 

designation in ephemeral waters paradoxically could be used to mandate that these waters be identified 

for Tier 2 protection, given that the waters have not been assigned a consumption of aquatic life use. 

They suggested that EPA clarify the rule text to focus on waters identified as impaired under CWA 

303(d), or to refer to uses “that have been designated for the waters” rather than referring to the uses 

specified in CWA 101(a)(2). EPA clarifies here that the final rule does not require that states and 

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authorized tribes provide Tier 2 protection to water bodies that do not have designated uses reflecting 

all of the uses specified in CWA 101(a)(2). The commenters focused on relating antidegradation Tier 2 to 

designated uses, however, in the final rule, 40 CFR section 131.12 directs states and authorized tribes to 

provide Tier 2 protection based on where water quality exceeds levels necessary to support fish, 

shellfish, and wildlife, and recreation in and on the water. It does not matter what uses are designated

by the state or authorized tribe. If water quality exceeds levels necessary to support uses specified in 

CWA section 101(a)(2), that assimilative capacity is the water quality that Tier 2 protection can help 

maintain. If a particular water has undergone a use attainability analysis (UAA) to remove or decline to 

designate a use specified in CWA section 101(a)(2) use because it is not attainable, this could be one of 

the factors that the state or authorized tribe could use to justify declining to provide Tier 2 protection. 

EPA points out also that what “support of the CWA 101(a)(2) goals” looks like can be different in 

different waters. For example, what would naturally be expected in an ephemeral water in the arid 

southwest would differ from what would naturally be expected in northwestern salmon runs. See essay 

7.e.iv for more information on comments about possible connections between UAAs and Tier 2.

D. Comments on Tier 2.5 

The federal regulation does not contain a “Tier 2.5” concept, though EPA recognizes that some states 

and authorized tribes use this concept to describe protection that is more protective than Tier 2 and less 

protective than Tier 3. Commenters recommended that EPA consider finalizing changes to the 

regulation explicitly allowing states and authorized tribes to differentiate between “Tier 2” and “Tier 

2.5,” where “Tier 2.5” represents waters identified by states’ and authorized tribes’ own 

antidegradation regulations as receiving a level of protection greater than for Tier 2 but less than for Tier 

3. Commenters suggested that EPA allow for differentiation between how states and authorized tribes 

identify waters for Tier 2 and Tier 2.5 protection, and that Tier 2 should be subject to less rigorous 

analysis, for example, the social and economic evaluation for “lesser Tier 2 waters” could be less 

rigorous than what is required for all Tier 2 waters. Tier 2.5 is outside the scope of this rulemaking. EPA 

did not propose any requirements for a new antidegradation tier and is not finalizing any requirements 

for Tier 2.5. However, they still have the obligation that any requirements for Tier 2.5, if they employ 

such a category, be at least as protective as what the federal regulation requires for Tier 2.

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Essay 7.d.iii – Antidegradation and High Quality Waters: How Tier 2 

Review is Conducted

A. Comments regarding Tier 2 Reviews

In the proposal preamble, the U.S. Environmental Protection Agency (EPA) stated that it was considering 

whether to specify in regulation how states and authorized tribes determine for which parameters Tier 2 

review must be conducted depending on the approach used to identify high quality waters. As EPA 

stated in the proposal preamble, EPA has made a variety of different statements providing guidance and 

recommendations for how to conduct Tier 2 reviews once a water body is identified as receiving Tier 2 

protection. EPA requested comment on whether, once a high quality water is identified, the Tier 2 

review process for that water body should differ depending on the approach used to identify it as high 

quality. EPA stated that one option would be that the Tier 2 review process would be the same no 

matter how the state or authorized tribe identified the water as receiving Tier 2 protection: EPA would 

specify that for the water body-by-water body approach Tier 2 reviews must be conducted for all 

parameters for which the water quality has been identified as better than the applicable criteria 

developed to support the Clean Water Act (CWA) 101(a)(2) uses. A second option was that EPA could 

specify that for waters identified as high quality on a water body-by-water body basis, Tier 2 reviews are 

only required for parameters associated with the 101(a)(2) uses currently being supported. A third 

option was that EPA could specify that states and tribes have discretion on how to conduct the Tier 2 

reviews. EPA received far fewer comments on this topic (as opposed to the other topics in the proposal 

such as alternatives analysis and implementation methods). After considering the comments on this 

topic, the Agency ultimately chose not to specify in the regulation which parameters states and 

authorized tribes must include in their Tier 2 review when using the water body-by-water body 

approach. The Agency determined that this topic is more appropriately discussed in guidance. 

EPA had requested comment on several different options, including the following option: “...for the 

water body-by-water body approach the EPA could specify that Tier 2 reviews must be conducted for all 

parameters for which the water quality has been identified as better than the applicable criteria 

developed to support the CWA 101(a)(2) uses.” EPA considered comments supporting this option. EPA 

also considered comments saying that EPA should require alternate approaches in the regulatory text 

(e.g., codify that states and authorized tribes have discretion regarding which parameters receive Tier 2 

review once a water is identified for Tier 2 protection under the water body-by-water body approach). 

Some comments stated that a fundamental principle under the CWA is that the primary responsibility 

for establishing and implementing water quality standards (WQS) is with states and authorized tribes, 

and that allowing discretion on this point would best recognize the states’ and authorized tribes’ 

primary role. Some comments stated that EPA’s regulation should specify that discretion is allowed, in 

order to provide flexibility for different states and authorized tribes to craft approaches appropriate to 

their conditions and needs. They pointed out that decisions on allowing or not allowing degradation 

pursuant to a Tier 2 review are localized determinations. EPA acknowledges states’ and authorized 

tribes’ primary role in developing their own WQS. EPA’s view is that states and authorized tribes already 

have discretion to identify which waters receive Tier 2 protection, including the discretion to do this on a 

site-specific basis, provided their approach is consistent with the federal regulation. EPA’s view is that in 

order to provide the appropriate protection to waters identified for Tier 2 protection under the water 

body-by-water body approach, the plainest and most consistent reading of section 131.12(a)(2) is as 

follows: no matter how a water body is assigned Tier 2 protection (on a water body-by-water body basis 

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or on a parameter-by-parameter basis), once the water body is identified for Tier 2 protection, the state 

or authorized tribe conducts the Tier 2 review for all parameters for which water quality is better than 

CWA 101(a)(2) levels. This is because “where the quality of the waters exceeds levels necessary to 

support the protection and propagation of fish, shellfish, and wildlife and recreation in and on the 

water” (that is, where a water has been identified for Tier 2 protection), “that quality shall be 

maintained and protected” unless the state or authorized tribe makes a finding to allow degradation 

through a Tier 2 review. While the final rule allows discretion in how waters are identified for Tier 2 

protection, the requirement “that quality shall be maintained and protected” unless a finding is made 

otherwise applies to all parameters in all waters identified for Tier 2 protection. EPA views this 

interpretation as clearly consistent with the CWA as it provides Tier 2 protection to high quality waters 

on the parameters for which those waters are high quality. Thus this interpretation provides more 

assurance that the water quality shall be maintained and protected. Furthermore, this interpretation 

facilitates public transparency about what is and is not receiving Tier 2 protection. The final rule requires 

that states and authorized tribes using a water body-by-water body approach must involve the public on 

any decisions about whether they will provide Tier 2 protection to a water body, and the factors 

considered in such decisions. EPA’s view is that the most transparent and straightforward approach is to 

provide Tier 2 protection to all parameters with high quality in a water identified as Tier 2. This way, no 

matter whether the state or authorized tribe identifies waters for Tier 2 protection on a parameter-byparameter basis or a water body-by-water body basis, when the public is informed that waters are 

identified for Tier 2 protection, it is clear that all the parameters with high water quality in those waters 

will receive Tier 2 protection.

EPA clarifies here that the interpretation described in previous paragraph does not mean that, under the 

water body-by-water body approach, Tier 2 review is required for all waters where water quality is 

better than criteria reflecting CWA 101(a)(2) uses for at least one parameter. That would essentially be 

equivalent to requiring the parameter-by-parameter approach for all waters. Instead, states and 

authorized tribes using the water body-by-water body approach are still able to exclude waters from 

Tier 2 protection entirely, if they do so consistent with the requirements of the final rule. Once a water 

is excluded from Tier 2 protection on a water body-by-water body basis, Tier 2 review is not required, 

even if the water’s levels of some parameters are better than criteria reflecting CWA 101(a)(2) uses. 

Some commenters incorrectly stated that EPA’s proposal preamble said EPA might require Tier 2 review 

for all parameters for which water quality is better than the criteria. The proposal preamble did not say 

this. It asked for comment on whether, once a water is identified for Tier 2 protection on a water bodyby-water body basis, Tier 2 reviews must be conducted for all parameters for which the water quality 

has been identified as better than the applicable criteria developed to support the CWA 101(a)(2) uses. 

The approach described in the proposal preamble is different in two ways from these commenters’ 

statements: 1) it focuses only on what occurs once a water is already identified for Tier 2 protection on a 

water body-by-water body basis (so, not relevant to waters that are identified as not receiving Tier 2 

protection), and 2) it is specific to criteria to support CWA 101(a)(2) uses (rather than all criteria.)

A comment stated that since Tier 2 reviews are related to water quality-based effluent limits (WQBELs), 

the best approach is for the antidegradation Tier 2 analysis to be conducted for the individual 

parameters relevant to the discharge. This comment is outside the scope of this rulemaking, which does 

not address the ways in which Tier 2 review ties directly in to WQBEL development. For more 

information on WQBEL development, please see EPA’s NPDES Permit Writers’ Manual

(http://water.epa.gov/polwaste/npdes/basics/NPDES-Permit-Writers-Manual.cfm).

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A comment pointed to EPA’s 1998 Advance Notice of Proposed Rulemaking (ANPRM) at p. 36782 as 

justification for the argument that the available assimilative capacity for any given pollutant must always 

be subject to Tier 2 protection (regardless of how the state or authorized tribe identifies its waters for 

Tier 2 protection.) EPA disagrees with the characterization of the ANPRM citation. The ANPRM citation 

reads as follows: “Existing approaches for identifying high quality waters fall into two basic categories: 

(1) pollutant-by-pollutant approaches, and (2) water body-by-water body approaches. States and Tribes 

following the first approach determine whether water quality is better than applicable criteria for 

specific pollutants that would be affected by the proposed activity. Thus, available assimilative capacity 

for any given pollutant is always subject to tier 2 protection, regardless of whether the criteria for other 

pollutants are satisfied...States and Tribes following the second approach weigh a variety of factors to 

judge a water body segment’s overall quality...Under this water body-by-water body approach, 

sometimes referred to as the ‘‘designational’’ approach, assimilative capacity for a given pollutant may 

not be subject to tier 2 protection if, overall, the segment is not deemed ‘‘high quality.’’” The citation 

says that under the parameter-by-parameter method, Tier 2 protection is indeed provided to all 

parameters related to uses specified in CWA section 101(a)(2) for which assimilative capacity exists.

However, under the water body-by-water body approach (previously, and as modified by the final rule), 

states and authorized tribes may choose to identify waters to exclude from Tier 2 review in a number of 

different ways consistent with the final rule requirements. Therefore, under the water body-by-water 

body method, there are circumstances under which the available assimilative capacity for any given 

pollutant will not be subject to Tier 2 protection. As stated in the ANPRM, if a water body is deemed 

overall “not high quality,” Tier 2 review protection would be denied for all parameters (as long as the 

makes this decision consistent with the final rule). This is still true under the final rule. Elsewhere in this 

essay EPA discusses the question of which parameters receive Tier 2 review, once a water is identified 

for Tier 2 protection.

Some commenters who expressed a preference for EPA to adopt a final rule requiring use of the 

parameter-by-parameter approach stated that if EPA declined to do so and allowed use of the water 

body-by-water body approach, EPA should at minimum require that waters that are attaining uses 

specified in CWA section 101(a)(2) to be protected as to the uses they are attaining. That is, states and 

authorized tribes would have to provide Tier 2 protection for every water body for all parameters 

relating to the 101(a)(2) uses the water is attaining. Under the commenters’ suggestion a state or 

authorized tribe would only be able to exclude a water from Tier 2 protection if water quality does not 

support any of the uses specified in CWA section 101(a)(2). EPA disagrees with this suggestion because 

this would remove considerable state and authorized tribal flexibility to identify which of their waters 

will receive Tier 2 protection and which will not under a water body-by–water body approach. EPA’s 

view is that states and authorized tribes should be able to identify waters that will not receive Tier 2 

protection, even when those waters may be exceeding levels necessary to support a 101(a)(2) use 

because of other factors identified through a holistic evaluation. The approach in the final rule provides 

a balance between preserving state and authorized tribal flexibility to use the water body-by-water body 

approach as a way of managing resources and providing some limitations so that such an approach is 

used in a manner at least minimally consistent with the intent of the Act and 131.12(a)(2).

EPA agrees with comments stating that the Tier 2 analysis is only conducted for parameters for which

the water quality is better than the applicable water quality criteria reflecting 101(a)(2) levels

(i.e., where high water quality exists). The state or authorized tribe would then decide how much of the 

remaining assimilative capacity to delegate, if any, to that particular discharge. A comment suggested 

that the final regulatory text explicitly specify that Tier 2 reviews be confined to only those parameters 

associated with the uses specified in CWA 101(a)(2). This interpretation is a plain reading of the text, 

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thus, EPA found it was unnecessary to include additional language. EPA reiterates the agency’s

interpretation here.

Some comments objected to EPA’s proposal because it did not state that Tier 2 protection should only 

apply to those parameters (or uses) that attain Tier 2 status, when not all of the uses specified in CWA 

101(a)(2) are attained. Comments said that the rule language needed further clarification to limit Tier 2 

review to those uses and parameters that are attained to the extent that they qualify as “high quality 

waters.” EPA agrees with part of this: if a parameter is not meeting levels necessary to support a use 

specified in CWA section 101(a)(2), then there is no high quality (“assimilative capacity”) on which to 

conduct Tier 2 review, so Tier 2 protection cannot be provided. However, it is possible to provide Tier 2 

protection for parameters associated with uses that are not met. For example, an aquatic life use might 

not be met because of mercury levels, but many other parameters associated with aquatic life uses have 

assimilative capacity. States and authorized tribes have discretion to identify which of their waters will 

receive Tier 2 protection, as long as that is done consistent with the final rule requirements. Elsewhere 

in this essay EPA discusses the question of which parameters receive Tier 2 review, once a water is 

identified for Tier 2 protection.

A comment stated that EPA should continue to leave the form of Tier 2 review to the states and 

authorized tribes, requiring only that any water body or parameter that is supporting a designated use 

be subject to an appropriate Tier 2 review before “reducing its designated use protection.” EPA 

disagrees that Tier 2 review is a precursor to reducing a water body’s designated use protection. The 

designated uses of a water body are applicable regardless of whether Tier 2 review results in authorizing 

lowering of high water quality. High water quality may only be lowered down to the level that is 

supportive of all the water body’s designated uses, even after a Tier 2 review. EPA discusses its response 

to requests for allowing discretion about which parameters receive Tier 2 review elsewhere in this 

essay. 

Some comments stated that EPA’s proposed limitation on the water body-by-water body approach (that 

waters not be excluded solely because not all of the uses specified in CWA 101(a)(2) are attained) 

implies that EPA would evaluate and review high quality waters on a parameter-by-parameter basis 

regardless of the State's determination and identification of high quality waters. Please see response 

essay 7.d.ii for EPA’s response.

B. Comments That EPA’s Restrictions on Water Body–by–Water Body 

Approach Contradicts Previous Positions and Court Rulings

EPA disagrees with comments opposing the proposed change to the regulation regarding identification 

of high quality waters on the basis that the change contradicts EPA’s previously published position 

regarding the water body-by-water body approach in the 1998 Advanced Notice of Proposed 

Rulemaking, 63 FR 36742 (July 7, 1998), the court decision in United States Court of Appeals for the Sixth 

Circuit in Ky. Waterways Alliance v. Johnson, 540 F.3d 466 (6th Cir. 2008), the court decision in Ohio 

Valley Environmental Coal. v. Horinko, 279 F. Supp. 2d 732 (S.D.W. Va 2003), EPA’s approval of 

Kentucky’s antidegradation Policy Implementation Methodology in 2010, and other EPA approvals of 

state programs. Commenters suggested that EPA’s inclusion of language that calls into question that 

court decision is likely to prompt litigation. EPA acknowledges that the final rule adds limitations to the 

states’ and authorized tribes’ use of the water body-by-water body approach, while EPA’s previous 

regulation at Title 40 of the Code of Federal Regulations (CFR) Part 131.12(a)(2) did not impose 

limitations. However, this change is within EPA’s legal authority and is appropriate. EPA’s authority to 

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revise the antidegradation regulations is detailed in the preamble to the final rule, proposal, and 

elsewhere in the comment response document. EPA’s authority comes from section 501, 101, and 303 

of the CWA. The cases cited interpreted the regulations that existed at the time of the challenged 

decisions. The new regulations which are will supersede the old regulations. The previous WQS 

regulation did not limit the use of the water body-by-water body method, so under that regulation, EPA 

had no basis for disapproval of a state’s or authorized tribe’s water body-by-water body methods 

provided the state’s or authorized tribes’ methods were otherwise consistent with 40 CFR 131.12(a)(2). 

Thus EPA’s 2005 and 2010 approvals of Kentucky’s water body method and EPA’s defense of the state’s 

approach in the litigation were consistent with the applicable version of 40 CFR 131.12(a)(2) at that 

time. The 2008 KWA court opinion upheld EPA’s approval of the state’s approach because it deferred to 

EPA’s longstanding interpretation of its regulation effective at that time regarding high quality waters. 

(Similarly, the 2003 Ohio Valley opinion deferred to EPA’s interpretation of its regulation at the time.) 

Commenters pointed to EPA’s statement in the 1998 ANPRM that “the waterbody-by-waterbody 

approach” allows States and Tribes to focus limited resources on protecting higher-value State or Tribal 

Waters” (ANPRM, 36783). However, commenters failed to point out that in the same paragraph, EPA 

articulated its concerns about the water body approach: “However, the flexibility of the water body-bywater body approach is also its principal disadvantage where a State or Tribe does not develop inclusive 

qualification criteria. For example, where a State’s or Tribe’s implementation guidelines define a narrow 

universe of waters, many deserving high quality waters may not receive tier 2 protection. Thus water 

quality may actually decrease in the waters not classified for tier 2 protection without a public review of 

the development decision.” So, while the applicable regulation before the publication of this final rule 

did not impose restrictions on the water body-by-water body method, EPA had indicated publicly as 

early as 1998 that it had concerns about how an unrestricted approach could be consistent with the 

goals of the CWA and the WQS regulation. This answers commenters’ question about why EPA would 

seek to make a change to the requirements for identification of waters for Tier 2 protection given EPA’s 

previous approvals of and defense of the water body-by-water body approach.

C. Comments regarding the Burden of Tier 2 Review

For a response to these comments, please see response essay 7.d.ii and response essay 12.a. for a 

discussion of EPA’s economic analysis (EA) which accounts for any burden and costs associated with 

today’s antidegradation requirements.

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Essay 7.e – Antidegradation: Alternatives Analysis

No comments are assigned to this issue category, and thus no response is necessary.

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Essay 7.e.i – Antidegradation Alternatives Analysis: General Support for 

Proposed Revision

A. Comments That Generally Support the Proposed Requirement

The U.S. Environmental Protection Agency (EPA) agrees with comments regarding analysis of 

alternatives in Tier 2 review saying that such regulatory expectations will increase effectiveness of Tier 2 

and promote needed consistency. EPA agrees that the proposed requirement would have supported the 

overall purpose of the Clean Water Act (CWA), and EPA’s view is that the final rule does so as well. EPA 

agrees that the proposal and final rule requirement is explicitly stating what would naturally be 

expected when deciding whether a lowering (beyond de minimis amounts, if a state or authorized tribe 

exempts de minimis degradation) is necessary to accommodate important economic or social 

development. In development of the final rule, EPA reviewed and considered the examples provided by 

commenters which sought to illustrate circumstances where conducting an analysis of alternatives 

would have been helpful. 

EPA agrees that the analysis of alternatives should be an open and transparent process. EPA agrees that 

the proposed discussion of what “practicable” means and EPA’s inclusion of a definition of “practicable” 

in the final rule will allow enough factors to be weighed in the overall reasonable consideration of both 

the finding and possible alternatives, without making the review “strict in theory, fatal in fact,” as the 

commenter noted. EPA agrees that the final rule provides states and authorized tribes flexibility while 

still preventing or lessening degradation to waters, where possible. EPA disagrees that the previous Tier 

2 regulation stated that “1) whether allowing lower water quality is necessary to accomplish the 

proposed activity, typically by examining alternative ways of accomplishing the activity through an 

alternatives analysis; and 2) whether the proposed activity that will result in lower water quality will 

accommodate important economic or social development, through a socio-economic analysis.” The 

language of the Tier 2 regulation prior to today’s rule stated: “Where the quality of the waters exceeds 

levels necessary to support the protection and propagation of fish, shellfish, and wildlife and recreation 

in and on the water, that quality shall be maintained and protected unless the State finds, after full 

satisfaction of the intergovernmental coordination and public participation provisions of the State’s 

continuing planning process, that allowing lower water quality is necessary to accommodate important 

economic or social development in the area in which the waters are located. In allowing such 

degradation or lower water quality, the State shall assure water quality adequate to protect existing 

uses fully. Further, the State shall assure that there shall be achieved the highest statutory and 

regulatory requirements for all new and existing point sources and all cost-effective and reasonable best 

management practices for nonpoint source control.” That said, some states may have conducted or 

required alternatives analyses prior to this final rule and that would not have been inconsistent with the 

regulation. Prior to today’s rule, the regulation did not explicitly mention an alternatives analysis.

B. Comments regarding Degradation Only Where “Necessary” 

A commenter stated that degradation should only be allowed when absolutely necessary. The 

commenter did not specify how they would define “absolutely necessary,” but EPA’s regulations clearly 

indicate that degradation may be allowed if necessary to accommodate important economic or social 

development. Some commenters stated that any decision to reduce high quality water protection must 

include an analysis of alternatives to avoid or minimize degradation. EPA points out that some states 

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and authorized tribes may exempt some activities that would degrade high water quality from Tier 2 

review by using de minimis exemptions as described in the preamble to the final rule. In such cases, an 

analysis of alternatives would not be necessary if the degradation was de minimis. Please see response 

essay 7.i. for further discussion on de minimis. 

Commenters stated that by definition degradation cannot be “necessary” unless there are no 

alternatives available. EPA agrees that, in principle, making a determination that degradation is 

“necessary” requires an examination of whether alternatives could prevent the degradation. However, 

EPA also recognizes that not every alternative that might be theoretically “available” is appropriate for 

implementation. The final rule provides that in order to make the finding that a lowering is “necessary” 

a range of practicable alternatives that would prevent or lessen degradation associated with the 

proposed activity shall be evaluated. The rule does not require an evaluation of alternatives that are not 

practicable (a term defined by the final rule). 

C. Comments on the Level of Detail

EPA received a comment that EPA should put in rule its sentence in the preamble to the proposed rule 

explaining that the alternatives analysis should tailor the level of documentation and detail to the 

significance and magnitude of the particular circumstances encountered. The commenter thought that 

this was a very important concept that should be in rule rather than “in unenforceable and easily missed 

in preamble language.” EPA agrees this is a very important concept and EPA made a similar statement in 

the Water Quality Guidance for the Great Lakes at Title 40 of the Code of Federal Regulations (CFR) Part 

132, in appendix E. However, EPA does not agree that the commenter’s suggested language should be 

included in the water quality standards (WQS) regulation. The final rule preamble states “...the analysis 

should document a level of detail that reflects the significance and magnitude of the particular 

circumstances encountered, to provide the public with the necessary information to understand how 

the state or authorized tribe made its decision,” thus providing the appropriate guidance to states and 

authorized tribes. This final regulation provides some specific changes to the water quality standards 

regulation, while the Great Lakes Initiative (GLI) was a more extensive regulation that addressed many 

issues. Therefore, EPA chose to address this point in the preamble to the final rule. While not a part of 

the regulatory text, the preamble is included in the Federal Register (FR) notice and accessible to states, 

tribes, and the public.

D. Comments That EPA Should Require the “Least Degrading Practicable 

Alternative” 

Some commenters suggested that EPA require states and authorized tribes to choose the “least 

degrading alternative” or the “least degrading practicable alternative” to implement. The preamble to 

the final rule explains that EPA chose not to require implementation of the least degrading practicable 

(or least degrading) alternative to allow states and authorized tribes the flexibility to balance multiple 

considerations. Some alternatives to lowering water quality can have negative environmental impacts in 

other media (e.g., air, land). For example, incinerating pollutants rather than discharging the pollutants 

to surface waters could adversely impact air quality and energy use, and land application of pollutants 

could have adverse terrestrial impacts. EPA recommends that states and authorized tribes consider 

cross-media impacts and, where possible, seek alternatives that minimize degradation of water quality 

and also minimize other environmental impacts. Please see response essay 7.e.iv for additional 

discussion.

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E. Comments on Additional Guidance

Commenters suggested that EPA provide guidance to clarify expectations and to explain how to 

successfully conduct an analysis of alternatives. EPA intends to provide additional guidance on analysis 

of alternatives subsequent to the publication of this final rule. 

F. Comments on Alternatives to Be Identified

Some comments suggested that EPA amend its rule to specify “...If the State can identify any practicable 

and economically viable alternatives, the State may choose.....” EPA agrees that the alternatives must be 

economically viable, but rather than amend the rule language as suggested by the commenter, EPA 

included a regulatory definition of “practicable” which says “Practicable, in the context of 

§ 131.12(a)(2)(ii), means technologically possible, able to be put into practice, and economically viable.”

G. Comments on the Context of Alternatives Analysis

Some comments asked EPA to clarify in what context an alternatives analysis is required. They suggested

that traditionally, the analysis (along with the rest of Tier 2 review) has always been performed in the 

context of permitting. For a response to these comments, please see response essays 7.f.i paragraph I 

and 7.g.iii paragraphs C, K, and M. 

H. Comments on Water Quality Standards Variances

For responses to comments on WQS variances, please see the response essays 8.a. – 8.m. and response 

essay 8.i. on variance renewals.

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Essay 7.e.ii – Antidegradation Alternatives Analysis: General Opposition

for Proposed Revision

A. Comments in Support for Alternatives Analyses

The U.S. Environmental Protection Agency (EPA) agrees with comments stating that an alternatives 

analysis is a key component of antidegradation implementation and that it is important such an analysis 

look at alternatives that eliminate or minimize water quality impacts for reasons described in the 

proposal preamble.

B. Comments That Requiring an Alternatives Analysis Is Redundant or 

Unnecessary

EPA disagrees with comments stating that the proposed requirement to conduct an analysis of 

alternatives was redundant of already existing language at section 131.12(a)(2) that requires states and 

authorized tribes to protect existing uses fully and assure that there shall be achieved the highest 

statutory and regulatory requirements for all new and existing point sources and all cost-effective and 

reasonable best management practices (BMPs) for nonpoint source (NPS) control. However, the existing 

requirements referred to by the comments relate to existing uses and other point sources and NPS, but 

did not specifically require an analysis of alternatives to determine whether a lowering of high water 

quality is “necessary.” The specific requirement for analysis of alternatives is not redundant.

EPA disagrees with comments stating that a requirement to conduct an analysis of alternatives is 

unnecessary. EPA determined that in order for a state or authorized tribe to make a credible finding that

allowing lower water quality is “necessary,” the finding must be based on an analysis of alternatives to 

the proposed lowering, resulting in either preventing the degradation, or only allowing as little 

degradation as is actually necessary. Without an analysis of practicable alternatives, a finding that a 

lowering of water quality is “necessary” is lacking in a key piece of information – whether there are 

other practicable options that could work instead with less degradation than the proposed alternative. 

Without this type of analysis, EPA determined that states and authorized tribes cannot appropriately 

find that a lowering of water quality is necessary.

C. Comment That EPA’s Requirement Is Inconsistent with the Clean Water Act

and Previously Existing Regulation

EPA disagrees with comments stating that the proposed requirement is inconsistent with previously

existing antidegradation regulatory requirements and Clean Water Act (CWA) requirements and that the 

EPA should not allow degradation if there are alternatives. The CWA and EPA’s water quality standards 

(WQS) regulation have never prohibited degradation of high quality waters. The antidegradation 

provisions have never been intended to prohibit growth on or near high quality waters but rather to 

require states and authorized tribes to evaluate whether such degradation is necessary prior to allowing 

degradation. Section 131.12(a)(2) requires high water quality to be maintained and protected unless the 

state or authorized tribe finds that the lowering of water quality is “necessary to accommodate 

important economic or social development in the area in which the waters are located.” The intent of 

that provision is to allow states and authorized tribes the flexibility to make informed, decisions about 

whether it is necessary to allow degradation of high water quality. The new requirement at Title 40 of 

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the Code of Federal Regulations (CFR) section 131.12(a)(2)(ii) explicitly requires consideration of 

alternatives that could be implemented to eliminate or minimize the lowering of high water quality in 

order to determine whether degradation is necessary. The new requirement specifically only requires 

consideration of alternatives that are practicable to implement, not “all” alternatives. If “all” alternatives 

were required to be considered, and if degradation were prohibited if any alternative was possible, the 

argument could be made that degradation is prohibited in all cases. This is because not allowing an 

activity is always an alternative, even if not always a practicable one (e.g., not allowing expansion of a 

wastewater treatment facility to accommodate increased urban development). Allowing states and 

authorized tribes the flexibility to make decisions about whether degradation of high quality waters is 

“necessary” based on an analysis of practicable alternatives, rather than prohibiting it at a federal level, 

is consistent with the CWA and the WQS regulation.

EPA disagrees with comments stating that the final rule should require that alternatives analysis include 

review the “least degrading” alternative and where appropriate, result in choosing the “least degrading” 

identified alternative in order to minimize impact to water bodies. EPA also disagrees with comments 

stating that the rule will give states and authorized tribes too much latitude to choose an alternative 

that would degrade water quality even when a non-degrading alternative is available. Comments stated 

that in this situation, lowering water quality is demonstrably not “necessary,” so the proposal is not 

consistent with the antidegradation requirements and the CWA goals. The language of the final rule 

requires an analysis of a range of practicable alternatives that would prevent or lessen degradation and 

allows states and authorized tribes the flexibility to make a finding that a lowering is “necessary” as long 

as a practicable alternative within that range is chosen to be implemented. The final rule recognizes that 

requiring a non-degrading alternative, or least degrading alternative, in all cases, could lead to adverse 

effects on other media (e.g., land, air). Further, alternatives may differ as far as economic viability and 

ease of implementation, which are factors important for states and authorized tribes to consider when 

making decisions about resources available for other water quality protection efforts. For example, a 

state or authorized tribe might choose an alternative to implement that is not the “least” degrading 

among the alternatives, but that is significantly less resource-intensive to implement, freeing up other 

state or authorized tribal resources to put towards complementary protection efforts. As part of the Tier 

2 review, analysis of alternatives are subject to public participation and intergovernmental coordination, 

which should provide transparency about factors in the decisions about lowering or maintaining high 

water quality. Thus, state and tribal decisions that a lowering of water quality is necessary will be more 

fully vetted and transparent to the public. EPA views the final rule provision on analysis of alternatives 

as an appropriate balance between protection of high water quality and state and authorized tribal 

flexibility that is consistent with the intent of the CWA and EPA’s regulatory language at section 

131.12(a)(2). Please see response essay 7.e.iv for additional discussion.

D. Comments about Who Has the Expertise to Make Decisions About 

Alternatives

EPA agrees with comments stating that states and authorized tribes, should not be required to spend 

resources conducting the analysis of alternatives and that they will not necessarily have the expertise or 

resources to conduct the analysis of alternatives in Tier 2 review. EPA agrees that manufacturing and 

business decisions are most appropriately made by the dischargers and that an analysis of alternatives 

can be (as they are typically done now) done by the discharger itself. The final rule language is written 

without predetermining what entity conducts the analysis providing the needed flexibility for the most 

appropriate entity to conduct the analysis of alternatives. As explained in the final preamble, the 

analysis of alternatives can be provided by one or more different entities as long as states and 

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authorized tribes make the final decisions authorizing degradation of high water quality based on a 

reasonable, credible, and adequate analysis of alternatives. 

EPA agrees that an applicant is ultimately in charge of the scope of its proposed project, however states 

and authorized tribes have no obligation to grant, certify or otherwise allow projects that degrade water 

quality. States and authorized tribes can deny permit applications or certifications. They can also require 

conditions in permit is that reflect modifications to the intended scope of a proposed project. EPA’s final 

rule does not change this existing state/authorized tribal discretion but rather helps ensure that states 

and authorized tribes have the appropriate information to make their decisions. Please see the 

preamble to the final rule for additional discussion.

E. Comments That the Alternatives Analysis and Selection Requirement 

Exceeds EPA’s Authority and Unnecessarily Expands Scope

EPA disagrees with comments stating that requiring an analysis of alternatives and the selection of a 

practicable alternative generally goes beyond EPA’s CWA authority and impermissibly expands EPA’s 

role. EPA also disagrees with comments that such requirements have no basis in standards established 

under section 303(c) of the Act. EPA provided a discussion of its CWA authority of antidegradation in the 

preamble to the proposed rule on page 54526 and is summarized in section D of the final rule and 

elsewhere in the comment response document. EPA’s revisions to the requirements at section 131.12 

are intended to ensure that state and authorized tribal antidegradation programs continue to be 

consistent with the purposes of the CWA, fully meet the requirements of EPA’s regulation, and that 

antidegradation decision-making is informed by examining alternatives and by public participation. 

EPA disagrees with comments that the fact that Congress outlined specific vetting of alternatives in 

other sections of the CWA (e.g., NEPA, and LEDPA analysis under CWA 404) is evidence that Congress 

knows how to communicate to agencies when it wants them to undertake alternatives analyses. EPA has 

authority under the CWA section 501 to promulgate regulations necessary to implement the CWA. It is 

not unusual for the CWA to lack detail regarding the implementation of the statute. Thus the EPA has

the authority to promulgate regulations to implement the purpose of the statute.

For these same reasons, EPA disagrees with comments that the proposal ranged further into 

implementation than its CWA authority allows, because the regulation dictates how an alternatives 

analysis shall be conducted and which alternative shall be chosen. The final rule does not dictate exactly 

how the analysis of alternatives must be conducted nor does it specify which alterative must be chosen.

Rather, it provides regulatory language to make clear that (1) an analysis of alternatives must be done, 

(2) the alternatives must be a range of practicable alternatives that prevent or lessen the degradation 

associated with the proposed activity, and (3) a state or authorized tribe shall only find that a lowering is 

necessary if one such practicable alternative is identified and selected for implementation. How the 

analysis is conducted is up to the entity conducting the analysis (and the state must base its decision on 

an adequate analysis), which alternative is selected from the list of practicable alternatives is up to the 

selector. But, EPA’s new regulations provide clarity on what must occur in order for the State’s or 

authorized tribe’s finding to be consistent with EPA’s regulations and with the CWA. This construct, in 

totality, is consistent with and furthers Congress’ clearly stated policy to “recognize, preserve, and 

protect the primary responsibilities and rights of States to prevent, reduce, and eliminate pollution [and] 

to plan the development and use (including restoration, preservation, and enhancement) of land and 

water resources...” Title 33 of the United States Code (U.S.C.) section 1251(b).

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EPA also disagrees with comments that EPA has no authority to mandate an alternatives analysis

because when EPA reviewed and approved Washington State’s antidegradation provisions in 2007, EPA

declined to review the following state provision: “The department retains the discretion to require that

the applicant examine specific alternatives, or that additional information be provided to conduct the

analysis.” EPA’s letter stated that EPA was not acting on the provision because examining specific

alternatives or requiring additional information was at the state’s discretion, and the provision was not a

new or revised WQS under section 303(c) of the CWA because it was a supplementary requirement 

beyond what the regulations required at that time. The provision referred to in the commenter’s 

citation is one that a state chose to adopt to give itself discretion to require an applicant to examine

specific alternatives or to require additional information. Please see “What is a New or Revised Water

Quality Standard under CWA 303(c)(3)? – Frequently Asked Questions” for the factors EPA considers

when evaluating whether a state provision is a new or revised WQS subject to EPA review at 

http://water.epa.gov/scitech/swguidance/standards/cwa303faq.cfm. Commenters conflated EPA’s 

authority to review state and authorized tribal adopted WQS with EPA’s authority to promulgate a

federal WQS regulation mandating analysis of alternatives in the context of Tier 2 review. As explained 

elsewhere in this response, EPA has the authority to establish federal regulations for antidegradation. At

the time of EPA’s decision, EPA found that the Agency did not have 303(c) review authority over the

Washington provision. EPA’s evaluation at that time of whether the provision was or was not a new or

revised WQS has no bearing on whether EPA has authority to promulgate national requirements

requiring an analysis of alternatives. 

EPA disagrees with comments stating that the proposed amendment exceeds EPA’s authority and could 

conflict with specific provisions of the CWA, including sections 301 and 303(c) because it would create a 

new effluent standard to be applied plant-by-plant. Comments stated that this would render the 

uniform technology-based requirements developed by EPA pursuant to section 301 almost entirely 

superfluous and bring the rule into conflict with these provisions in ways the existing policy does not. 

EPA’s technology based effluent standards are effluent quality requirements based on available 

technology, not requirements to install specific technologies. EPA does not dictate what technology 

dischargers must install in order to meet the effluent standard. WQS establish designated uses and 

criteria to protect those uses that could result in water quality-based effluent limits (WQBELs) that are 

more stringent than technology based effluent limits (TBELs). When conducting a Tier 2 review to 

identify alternatives to the degradation of water quality, EPA’s final rule does not pre-determine a 

particular alternative that must be implemented or that the permit must require a specific alternative to 

be implemented. Rather, when a state or authorized tribe makes a finding that a lowering of high water 

quality is “necessary,” that finding can only be made when a non-degrading or less degrading alternative

identified in the analysis of alternatives is selected to be implemented and therefore some lowering is 

still “necessary.” The permit would then determine the appropriate limit keeping in mind this particular 

alternative that the discharger will implement. Where the WQS lead to WQBELs that are more stringent 

than TBELs, it is possible that the discharger will need to implement a technology to meet that WQBEL 

that is different from the technology that the TBEL was based on. However, this does not mean that EPA 

is establishing new technology based effluent standards with its final rule. The outcome of these state 

and authorized tribal decisions inform how the specific activities are allowed (e.g., permitted, licensed, 

certified) on a case by case basis.

EPA disagrees with comments stating that the proposed requirement for alternatives analysis could 

effectively require states to conduct a “best available technology economically achievable” (BAT) 

analysis for every pollutant discharged for a project to high quality water, not just pollutants of concern 

as in a technology-based best professional judgement (BPJ) analysis under 40 CFR 125.3. The final rule 

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does not require BAT analysis but an analysis that would identify a range of practicable alternatives. As 

discussed in section F of this essay, requiring identification of a “range” is not the same as identification 

of all practicable alternatives. In addition, as discussed in section O of this essay, EPA’s definition of 

“practicable” in the context of 131.12(a)(2) is broader than just the “best available technology

economically achievable.” 

EPA disagrees with comments stating that the proposal regarding alternatives analysis would require a 

permit applicant to demonstrate that the least degrading alternative has been selected, requiring them 

to demonstrate that its level of treatment is the highest level technologically and economically 

achievable. A specific commenter states that this converts Tier 2 review into a form of new source 

performance standard (NSPS) assessment, which would inappropriately impose a technology-based 

analysis on a water-quality based issue. First, the proposal did not and the final rule does not require the 

permit applicant to select the least degrading alternative. Please see response essay 7.e.iv for additional 

discussion on the alternative to be selected. Second, the final rule requirements for analysis of 

alternatives in Tier 2 review are not equivalent to NSPS assessment. NSPS is defined at section 306 of 

the CWA. As discussed earlier in this section, when conducting a Tier 2 review to identify alternatives to 

the degradation of water quality, EPA’s final rule does not pre-determine a particular alternative that 

must be implemented by certain types of dischargers nor does the rule require that the permit must 

require implementation of a specific alternative. Rather, when a state or authorized tribe makes a 

finding that a lowering of high water quality is “necessary,” that finding can only be made when a “less 

degrading” alternative is selected to be implemented and therefore some lowering is still “necessary.” 

The permit would then determine the appropriate limit keeping in mind this particular alternative that 

the discharger will implement. The final rule is focused on the analysis that must occur before a state 

finds that a lowering is necessary. The rule does not establish any performance standard for dischargers 

or mandate any particular technologies.

EPA disagrees with comments that the proposal would give EPA the power of approval or disapproval 

over new development and land use decisions. EPA also disagrees that the proposal would engender 

even more involvement of EPA in State decision-making regarding wastewater planning, infrastructure, 

etc. The final rule does not give EPA any direct approval or disapproval authority over states’ and 

authorized tribes’ decisions to allow degradation (note, that EPA does have authority under section 

303(c) to approve or disapprove a new or revised state or tribal WQS). In the context of antidegradation, 

new or revised WQS would only be a new or revised antidegradation policy and/or a new or revised 

legally binding antidegradation implementation procedure. EPA partly agrees and partly disagrees with 

comments that the proposal preamble suggests EPA can overrule a decision to allow degradation, vastly 

broadening federal control over state antidegradation decisions. EPA can potentially overrule a decision 

to allow degradation; however, this was already the case under the previous regulation, based on EPA’s 

oversight authority in other programs. This rule does not alter the existing oversight authority EPA has

over National Pollutant Discharge Elimination Systems (NPDES) permitting programs and some other 

programs through which state and authorized tribes can allow degradation of high water quality. For 

example, EPA has the authority to object to an NPDES permit if the permit does not derive from and 

comply with the state or authorized tribe’s applicable WQS, including legally binding antidegradation 

requirements. States and authorized tribes always have the discretion to involve EPA as part of normal 

EPA/state working relationships. Under the final rule, the states and authorized tribes continue to have 

the authority to decide whether and in what instances to make a finding that a lowering of high water 

quality is “necessary.” 

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EPA generally disagrees with comments that the proposed change to analysis of alternatives greatly and 

unnecessarily expands the current scope of antidegradation analyses, will result in federal control of 

land use decisions, and is a new requirement. EPA has the authority to establish new requirements 

where necessary to implement the CWA. The alternatives analysis is a new requirement. However, this

final rule clarifies the requirement to find that degradation is “necessary” before allowing it, which 

previously existed, and makes explicit that the way to determine whether degradation is “necessary” is 

through an analysis of alternatives. EPA’s requirement that the state or authorized tribe may only make 

a finding if an identified non-degrading or less degrading practicable alternative is chosen for 

implementation is reasonable because EPA found, after considering the comments and stakeholder 

input, that the new requirement appropriately expresses what it means to find degradation “necessary.” 

EPA’s view is that a credible finding that degradation is “necessary” is not possible if the entity making 

that finding has no information regarding whether practicable alternatives exist. 

F. Comments That the Requirements Add Administrative Burden, Delay, and

Cost

Commenters objected to the proposal because they stated that it would cause substantial increased 

administrative burden and expenses for states, authorized tribes, and the regulated community because 

of the nature and amount of information required and the added complexity. Commenters provided no 

evidence or additional information for this assertion. The analysis of alternatives, as described explicitly 

in the final rule, is not inherently any more onerous or complicated than the previous rule’s requirement 

to find that degradation is “necessary.” In addition, the preamble to the final rule explains that 

regardless of the number of alternatives identified, the analysis should document a level of detail that 

reflects the significance and magnitude of the particular circumstances encountered, to provide the 

public with the necessary information to understand how the state or authorized tribe made its 

decision. Thus, the burden associated with the analysis can be commensurate with the significance and 

magnitude of the potential degradation. EPA recognizes that with its explicit requirements to conduct an 

analysis of alternatives and the range of practicable alternatives this analysis should include, some states 

and authorized tribes may incur additional costs and burden as a result of evaluating more extensive 

analyses of alternatives or even conducting these analyses if that is what the state or authorized tribe 

chooses. EPA’s economic analysis (EA) includes consideration of these costs and burden and can be 

found both in the preamble to the final rule and EPA’s full EA published at the same time as the final 

rule. As described in the preamble, EPA obtained more precise estimates of burden and costs for this 

rule as a result of engaging states, as requested by them during the comment period, and EPA 

incorporated the information provided into its final EA. 

Commenters stated that the simplistic description of practicable alternatives described in the proposal is 

inadequate and understates the complexity of evaluating alternatives to prevent or limit lowering of 

existing high water quality. In addition, commenters expressed concern that the open ended nature of 

the analysis could add so much time that a project will be cancelled just because of the time needed.

EPA disagrees. EPA disagrees with comments that the proposal would require extensive, expensive, and 

repetitive studies because of differing opinions regarding whether all possible alternatives have been 

evaluated and whether any of them meet the definition of “practical”. The final rule provides a clear 

guideline that the analysis of alternatives shall evaluate a range of practicable alternatives, not ALL 

practicable alternatives. EPA received comment on this point and agrees. In addition, the final rule is 

written to intentionally allow states and authorized tribes to consider a variety of factors when 

evaluating the range of alternatives that prevent or lessen degradation and the alternative to be 

implemented when deciding whether a lowering of high water quality is “necessary.” EPA’s rule does 

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not predetermine exactly how the analysis and the selection of an alternative is to occur; it can be 

complex or simple at the state or authorized tribe’s discretion, as long as it supports the 

states’/authorized tribes’ final determination that degradation is “necessary.” 

EPA agrees with comments that it should not be the states’ and authorized tribes’ burden to perform an 

alternatives analysis on a potentially unlimited number of scenarios. As discussed in section D, EPA’s 

final rule makes clear that any entity can conduct the analysis of alternatives as long as states and 

authorized tribes make the final decisions authorizing degradation of high water quality based on a 

reasonable, credible, and adequate analysis of alternatives. 

EPA disagrees with comments stating that the proposed alternatives analysis is particularly onerous, 

essentially forcing states to perform a use attainability analysis (UAA) when implementing State 

antidegradation provisions. The commenters provided no explanation for these assertions. A Tier 2 

analysis of alternatives is distinct and different from a UAA. A UAA is a structured scientific analysis of 

factors affecting the attainability of a designated use, as described in 131.10 and generally accompanies 

a designated use revision which must submitted to EPA for review and approval or disapproval. An 

alternatives analysis is an evaluation of alternatives to lowering high water quality that informs a state 

or authorized tribe’s finding that a lowering of high water quality is necessary. 

Comments stated that the expectation to consider potential cross-media impacts in alternatives 

analyses will place a significant economic burden on states and authorized tribes each time they conduct 

analysis. Please see section E of this essay for a discussion of why the final rule does not require 

considering potential cross-media impacts.

Finally, in response to the various concerns about potential additional resource burden on states and 

authorized tribes to consider alternatives, the final preamble points out that a state or authorized tribe 

can obtain already-compiled information on common practicable alternatives appropriate for a 

proposed activity from additional existing resources. For example, EPA’s Municipal Technologies website 

presents technology fact sheets to assist in the evaluation of different technologies for wastewater 

(http://water.epa.gov/scitech/wastetech/mtb_index.cfm).

G. Comments That EPA Must Retain Flexibility for States and Authorized 

Tribes

Commenters stated that EPA should recognize the difficulty of “approving or disapproving” the methods 

associated with an alternatives analysis, including any accompanying social/EA, if it were to mandate 

EPA review of the state implementation methods. The final rule does not mandate states and authorized 

tribes to adopt antidegradation implementation methods for EPA review and approval or disapproval. 

Please see section Q of this essay and response essay 7.f.i for additional discussion. EPA agrees with one 

commenter’s statement that states and authorized tribes “need local flexibility in fashioning the metrics 

associated with analysis of alternatives given the variety of situations they will face based on state 

statutory schemes, geographic and hydrologic differences, and local economic conditions.” However, 

EPA disagrees that this need for flexibility means that EPA should not promulgate a requirement for an

analysis of alternatives. The final rule allows the flexibility for states and authorized tribes to develop 

their own methods specific to local needs, to consider different alternatives in different situations

(e.g., different alternatives may be better in a facility in the arid west than in a similar facility in a rainy 

area in the southeast) when deciding whether to authorize a lowering of high water quality, and to 

consider local economic conditions in the social/EA. 

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EPA agrees with comments stating that States should be allowed flexibility in making the determination 

whether lower water quality is both necessary and will accommodate important economic and social 

development. EPA also agrees with commenters that the final rule should retain state and authorized 

tribal discretion to decide the sequence with which they satisfy the components of a Tier 2 review. The 

preamble to the final rule makes clear that states’ and authorized tribes’ have the flexibility, as 

requested by commenters and in fact that the states’ and authorized tribes’ finding that a lowering is 

necessary depends on both an analysis of alternatives and an analysis related to economic or social 

development. In addition, states’ and authorized tribes’ have the discretion to decide the order in which 

they satisfy both aspects of a Tier 2 review. 

EPA disagrees with comments that the proposed language was too restrictive because it said “will only” 

[make a finding to allow degradation... after conducting an alternatives analysis] and with suggestions 

that EPA should say “may.” The purpose of the revision is to make the requirement to conduct an 

analysis of alternatives consistent across the country so that states and authorized tribes have 

reasonable, credible, and adequate analysis of alternatives to base their decisions on. Saying that states 

and authorized tribes “may” make a finding after an analysis of alternatives would imply that states and 

authorized tribes are not required to do so and that they may make a finding to allow degradation in 

some other way, without the analysis of alternatives. The final rule makes clear that the decision to 

allow a lowering of water quality can only happen after an analysis of alternatives and that the State 

shall only find that a lowering is necessary if a practicable alternative, if identified, is selected for 

implementation. It is important to note that some of the concern regarding flexibility was tied to the 

belief that EPA was requiring states and authorized tribes to conduct the analysis of alternatives 

themselves. As discussed in section D, EPA’s final rule makes clear that the responsibility of the states’ 

and authorized tribes’ is to make the finding of “necessity” but that a 3rd party may conduct the analysis 

of alternatives.

Commenters objected to requiring selection of a “less degrading alternative” must be selected without 

identifying a baseline for comparison, because this would arbitrarily exclude a permit or license

applicant’s original proposal from ever being selected, even where it would represent the best balance 

of costs and benefits. Commenters also said that requiring the state to select a practicable alternative 

that prevents or lessens degradation is intrusive federal oversight. As discussed in section D. and the 

preamble, states and authorized tribes are not required to select the alternative to be implemented 

themselves. In addition, the final rule only requires that a practicable alternative from the range of 

practicable alternatives that would prevent or lessen degradation must be selected. If none of the 

alternatives are practicable, then the original proposal could be selected. Further, while the comments 

presume that the applicant proposes a specific activity and then performs an alternatives analysis, it is 

also possible that the applicant performs an alternatives analysis and subsequently identifies the 

alternative to propose, informed by that analysis.

EPA disagrees with comments that the requirement for a detailed, EPA-directed alternatives analysis 

unnecessarily interferes with the primacy of the states with respect to the establishment of WQS. The 

final rule does not require a specific level of detail for analysis of alternatives, and the preamble explains 

that the detail of the analysis can be commensurate with the magnitude of the project. The final rule 

does not put EPA in the position of directing states’ and tribes’ analyses of alternatives, and as discussed 

in section D, the preamble says that while states and authorized tribes are responsible for making a 

finding to allow a lowering of water quality based on a reasonable, credible, and adequate analysis of 

alternatives, they need not conduct the analysis or select the alternative themselves States and

authorized tribes continue to have the primary role in establishing their Tier 2 review protocols and 

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making their own Tier 2 decisions. The final rule provides a balance between increased specificity in the 

federal requirement to assure implementation of antidegradation requirements is consistent with the 

CWA and regulations and retaining state and authorized tribal flexibility to make decisions within that 

framework.

H. Comments That the Requirements Are Too Vague and Will Lead to 

Litigation

EPA received comments that the requirement for alternatives analysis was vague and confusing, and 

would therefore lead to litigation on the federal level and the state and authorized tribal level. 

Commenters attributed the “vagueness” to a variety of causes: that the proposal did not identify how 

states and authorized tribes were to choose among less degrading alternatives, that it did not explain 

what the “holistic” analysis described in the preamble must consist of, that it did not identify factors 

that could be used to reject a less-degrading alternative, that it did not propose regulatory definitions of 

“alternatives” or “practicability,” or that it did not outline under what circumstances it is necessary to 

authorize degradation if a less degrading alternative is available. Commenters also attributed the 

vagueness to the fact that the requirement is framed as something that must be “ensured” by a state’s 

or authorized tribe’s implementation methods (“[s]uch methods must ensure that...the state will only 

make a [Tier 2 finding]...after...”). Commenters pointed to concerns that legal challenges could come up 

regarding the requirement to perform alternatives analyses, the sufficiency of alternatives analyses, 

which alternatives are analyzed, what constitutes ‘practicable’ and how much evidence is needed to

prove an alternative is “not practicable,” what is “minimally degraded,” which alternative is chosen, and 

the Tier 2 applicability to waters listed as “impaired” under 303(d) (for a discussion on the potential for 

having to conduct antidegradation reviews for impaired waters, please see response essay 7.e.i). 

Commenters stated that the proposal created a seemingly unattainable standard of review, providing 

potential litigants a low bar for challenges to state permitting decisions. Commenters stated that 

vagueness would be a problem for both permit writers and reviewing courts, and that EPA should clarify.

EPA agrees that framing the requirement in a way that made states and authorized tribes solely 

responsible for conducting the analysis of alternatives and selecting the alternative was inappropriate 

because entities other than the state or authorized tribe may be best positioned to analyze alternatives 

to a proposed lowering of water quality, and the state or authorized tribe may choose to work with or 

employ another entity or multiple entities to conduct the analysis of alternatives. The final rule makes 

clear that the state or authorized tribe need not conduct the analysis of alternatives itself as long as it 

makes the ultimate finding to allow or not allow a lowering of water quality based on its consideration 

of the analysis of alternatives. The final rule does not frame the requirement in terms of something that 

must be “ensured” by states’ and authorized tribes’ implementation methods. However, EPA disagrees 

that additional clarity is needed. EPA recognizes that regulatory provisions which do not provide a great 

deal of detail can lead to challenges for permit writers or others implementing the standards and for 

courts reviewing actions related to the standards. Where the previous regulations provided no 

regulatory clarity on how to determine “necessity,” which could lead to challenge, the final regulation 

provides more clarity on what “necessary” means. Short of making the regulation completely 

prescriptive, there is no way to prevent litigation over what exactly is required by the regulation in the 

future. As discussed in section G, the final rule strikes a balance between providing boundaries and 

clarity on what the regulation means by the word “necessary,” and avoids overly prescriptive dictates to 

allow states and authorized tribes some flexibility to make decisions appropriate for the local situation. 

EPA’s view is that the level of detail in the final rule is appropriate for the regulation, while guidance is 

more appropriate for describing the specifics of how states and authorized tribes could conduct their 

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analyses. Commenters stated that some of the details that EPA explained in the proposal preamble were 

critical to help addressing the vagueness. EPA agrees and the final rule preamble provides additional and 

important information to which co-regulators and the regulated community can look for additional 

guidance. States and authorized tribes have the ability to reduce uncertainty for regulated entities in 

their jurisdictions by providing additional rules or guidance in their own antidegradation implementation 

methods that are complement but are more detailed than the federal requirements. EPA will consider 

providing additional guidance on antidegradation after publication of the final rule.

One commenter specifically expanded on the concern of vagueness by specifying that the necessity 

determination should be focused on the general necessity for the project and not on the necessity to 

establish any particular effluent limit. In this view, whenever it is necessary to authorize a new or 

expanded discharge, it is necessary to authorize a lowering of high water quality, however small. EPA 

disagrees. The final rule requires the state or authorized tribe to specifically allow a lowering of water 

quality (e.g., via specific effluent limits) if that degradation is “necessary.” The commenter said that if 

EPA believes that “necessity is about specific effluent limitations, then EPA must be clear where 

“necessary” is on the “spectrum between ‘mere convenience’ and ‘absolute physical necessity.’ EPA 

does not interpret its provision on “necessary” to mean “absolutely necessary” as the regulations clearly 

indicate that degradation may be allowed if necessary to accommodate important economic or social 

development. Interpreting it as “absolute” would mean that there is no flexibility and thus the least 

degrading alternative must be selected for implementation in all cases. The final rule does not require 

selecting the least degrading alternative. As discussed in section C of this response essay and response 

essay 7.e.iv, rather than requiring the least degrading practicable alternative, the selected alternative 

must be practicable, and states and authorized tribes have flexibility to choose among practicable 

alternatives based on considerations of economics and other environmental and social impacts.

I. Comments Questioning the Relationship of Antidegradation Alternatives 

Analysis and National Environmental Policy Act, 404, and 401 Certifications

Commenters requested clarification for how the proposed requirement for Tier 2 analysis of alternatives 

would apply in the case of a federal activity such as a water supply project subject to the National 

Environmental Policy Act (NEPA) process and 401 certification. Commenters asked how the 

antidegradation requirement would fit with either the NEPA “purpose and need” statement of the 

project proponent or the independent NEPA alternatives analysis. EPA also acknowledges comments 

stating that where a state conducts a 401 certification of a 404 permit issued by the Army Corps of 

Engineers, the Tier 2 review requirement for analysis of alternatives could overlap with the alternatives 

analysis required under NEPA and the alternatives analysis required by 404 permitting. This means that 

three separate forms of alternatives analysis would be conducted by separate agencies, and that while 

the analyses may be slightly different in scope, they are likely to be similar. EPA agrees that this is a 

possible outcome but, as discussed below, each analysis can inform the other.

The “analysis of alternatives” required as part of Tier 2 reviews (in section 131.12) is distinct from an 

alternatives analysis required in other programs, such as NEPA and CWA section 404 permitting. When a 

federally initiated activity such as a water supply project is proposed, NEPA requires an evaluation of the

project’s possible environmental effects. If the initial evaluation finds that it would have significant 

effects, or that it is unknown whether it would have significant effects, further analysis is required, 

including an analysis of alternatives to the environmental impacts. Regardless of the specific analyses 

required for a specific project under NEPA, if the project would impact water quality, it would be subject 

to 401 certification by the relevant state or authorized tribe. If the state or authorized tribe found that 

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the project as proposed would not be consistent with its WQS, the state or authorized tribe could deny 

certification and prevent the project. Alternatively, it could condition the certification in order to require 

additional measures to protect water quality consistent with its WQS.

In order to allow degradation that is consistent with WQS requirements, Tier 2 reviews must be 

consistent with section 131.12 and the state’s or authorized tribe’s own Tier 2 policy. The requirement 

for an alternatives analysis under NEPA is not equivalent to the requirements of section 131.12 for Tier 2 

analysis of alternatives. Therefore, it cannot necessarily serve to fulfill the requirements at section

131.12(a)(2). Additionally, some projects subject to NEPA are found to have “no significant impact” in 

the initial evaluation, exempting them from NEPA alternatives analysis. Because NEPA does not 

specifically focus on impacts to water, having “no significant impact” to the “environment” under NEPA 

does not mean that the project would not degrade water quality at all, or that it would not degrade 

water quality beyond what a state or authorized tribe considers de minimis. Thus, even if NEPA does not 

require an alternatives analysis for a project, a state’s or authorized tribe’s antidegradation 

requirements may still require a Tier 2 analysis of alternatives for that project.

While another analysis, such as a NEPA alternatives analysis, is not necessarily a substitute for an 

antidegradation analysis of alternatives, information and analyses gathered in the context of other 

statutory and regulatory programs can potentially inform a Tier 2 analysis of alternatives. On a case-bycase basis, states and authorized tribes may choose to leverage this information to streamline their 

decision-making processes to allow degradation of high quality waters.

In the case of activities subject to NEPA and 401 certification, the relevant state or authorized tribe has 

the power to use 401 certification to ensure that activities are consistent with the relevant WQS 

including antidegradation. It is likely in the project proponent’s and the state’s or authorized tribe’s 

interest to coordinate early on. Such coordination can help streamline the requirements. 

EPA disagrees with comments stating that the proposal would turn an antidegradation analysis of 

alternatives into a NEPA-like process because it would obligate a state to reject a proposal if there is a 

non- or minimally-degrading practicable alternative, and because alternatives analysis would be 

required to consider cross-media impacts. Under the final rule, states and authorized tribes need not 

abandon a project altogether simply because they identify a range of practicable alternatives that would 

prevent or lessen the degradation associated with the proposed activity. The state or authorized tribe 

may make a finding to allow the project to continue as long as one of the less- or non-degrading 

alternatives identified in the range is selected for implementation. As discussed in section E of this 

essay, the final rule does not require consideration of cross-media impacts. EPA encourages 

consideration of cross-media impacts when states are deciding whether to allow a lowering of high 

water quality. Information from a NEPA review could help inform consideration of cross-media impacts 

in a Tier 2 analysis of alternatives.

EPA agrees with comments stating that the examples of alternatives cited in the proposal preamble go 

beyond evaluation of whether more effective wastewater treatment technologies are technically and 

affordably available, but disagrees that it means the rule requires a NEPA-like alternative review 

analysis. The comment states that states and authorized tribes would potentially take the additional 

step of mandating process changes and/or business choices for the permittee unrelated to wastewater 

treatment technologies. EPA agrees that this is a possible outcome but not due to the regulatory 

requirements but because the states and authorized tribes chooses. Even prior to the revisions made in 

this final rule, the federal antidegradation regulation gives states and authorized tribes the authority to 

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make decisions about whether to allow lowering of high water quality (and if so, how much). 

Commenters stated antidegradation reviews should at most involve consideration of cost-effective and 

available wastewater treatment technologies that could reduce the degradation of a project as 

proposed, and that states and authorized tribes should not be in the business of directing industries as

to how to manufacture products or whether such products may even be permissibly produced as a part 

of an antidegradation review. The final rule does not mandate that states and authorized tribes make 

choices mandating process changes and/or business choices for the permittee unrelated to wastewater 

treatment technologies. But, states and authorized tribes have the discretion to determine what is 

required before allowing a lowering of high water quality. In addition, section D explains EPA’s final rule 

makes clear that states and authorized tribes are responsible for making a finding that a lowering is 

necessary before allowing a lowering of high water quality but are not necessarily required to conduct 

the analysis of alternatives or select the alternative to be implemented, themselves.

J. Comments Questioning the Relationship to Accommodation of Social or 

Economic Development

EPA disagrees with comments stating that the proposed alternatives analysis requirement would be 

inconsistent with the intent of considering the accommodation of important economic and social 

development. Commenters expressed concern that the requirement limited state and authorized tribal 

flexibility and specifically asked how the requirement to find degradation “necessary to accommodate 

important economic or social development” relate to the analysis of alternatives and social and 

economic development. Commenters also asked whether the state or authorized tribe must find the 

most protective alternative that would accommodate economic or social development, and what states 

and authorized tribes are supposed to do if there is a less degrading alternative but they have no 

authority to require it. The preamble to the final rule explains that the finding to allow degradation is 

composed of two analyses: the analysis of alternatives, and the social/EA, and that these may be 

performed in whichever order the state or authorized tribe chooses. The rule does not require states to 

mandate that the “least degrading” practicable alternative be selected for implementation, as discussed 

further in response essay 7.e.iv. Therefore, states and authorized tribes still have some flexibility to 

determine what is “necessary to accommodate important economic or social development.” Through 

the analysis of alternatives, states and authorized tribes must require implementation of a practicable 

less or non-degrading alternative in order to make a finding that lowering high water quality is necessary 

before authorizing that lowering. In cases where they do not have authority to require a particular 

alternative to occur (e.g., if the alternative relates to requirements for NPS, but the state itself does not 

have mandatory restrictions on NPS), they might determine that such an alternative is not practicable 

(e.g., if implementing it would force the state or authorized tribe to allocate unreasonable amounts of 

funding).

Commenters asked for clarity regarding what level of social and economic development could be used 

to justify degradation of high quality waters. EPA is not responding to these comments as these 

comments are beyond the scope of this rulemaking, which is focused solely on how to identify high 

quality waters, requirements to conduct an alternatives analysis and to select a practicable alternative 

from a range to implement, and transparency regarding antidegradation decisions and development and 

revision of implementation methods. EPA did not propose or solicit comment on what level of social and 

economic development could be used to justify degradation of high quality waters and the final rule 

does not alter the discretion States and authorized tribes continue to have in relation to these decisions.

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Comments stated that the EPA should not promote use of its 1995 Draft Interim Economic Guidance for 

Water Quality Standards. On the other hand, a comment stated that the 1995 Draft Interim Guidance 

may be useful in evaluating the alternatives to determine if a degrading alternative is necessary to 

accomplish the proposed activity. EPA appreciates the specific comments received, however EPA is not 

revising the Draft Interim Economic Guidance as part of this rulemaking. In addition, the document is 

not cited in EPA’s regulatory language. Therefore, states and authorized tribes are not required to use 

the processes described in it when conducting their Tier 2 reviews, designating uses, adopting variances, 

or for any other WQs purposes, although states and authorized tribes may find it useful in informing 

WQS decisions. In regards to using the Draft Interim Economic Guidance when revising designated uses 

or adopting WQS variances, these comments are outside the scope of this rulemaking because the 

guidance is intended to assist states and authorized tribes in determining whether attaining the 

designated use is not feasible because “controls more stringent than those required by sections 301(b) 

and 306 of the Act would result in substantial and widespread economic and social impact.” EPA did not 

propose or solicit comment on this issue and the final rule does not change the regulations in regards to 

this issue. EPA will consider whether additional or revised guidance is needed in regards to evaluating 

economic considerations after the final rule is published.

Commenters suggested that EPA’s rule continue to cost-effectiveness to be an important factor 

considered when selecting an alternative to be implemented since requiring a discharger to expend 

funds up to or near the thresholds expressed in the 1995 Interim Guidance for a minor improvement in 

surface water quality is a concerning policy. As discussed throughout this essay, specifically in sections C, 

D, and G, the final rule does allow cost-effectiveness to be considered when determining whether a 

lowering of high water quality is necessary. 

K. Comments That the Type and Number of Alternatives That Must Be 

Evaluated Is Excessive and EPA’s Requirement to Evaluate Them Goes beyond 

Clean Water Act Authority

EPA received many comments related to the practicable alternatives that must be evaluated under 

section 131.12(a)(2). The comments ranged from questioning the types of alternatives to how many 

alternatives that need to be evaluated.

With regard to the type of alternatives that need to be evaluated, EPA disagrees with comments that a 

“practicable alternative” goes beyond wastewater options and into considerations most states are not 

authorized to make and beyond the intent of the CWA. The final rule does not require states and 

authorized tribes to consider non-wastewater options, if they can identify a range of practicable 

alternatives related to wastewater options. The proposal provided an exhaustive list of types of 

alternatives that can be considered when developing a “range of practicable alternatives that would 

prevent or lessen degradation” as specified in the final rule. Specifically, EPA said “...this evaluation 

would include a consideration of any non-degrading or minimally degrading cost-effective pollution 

prevention alternatives and enhanced treatment techniques, but would not be limited to those. For 

example, alternatives could include no discharge, pollution prevention measures, process changes, 

reduction in the scale of the project, advanced or different treatment technologies, water recycling and 

reuse, land application, seasonal or controlled discharge options avoiding critical water quality periods, 

and alternative discharge locations, if such measures were practicable.” While it is true that “practicable 

alternatives” can be broadly interpreted, EPA’s final rule requires a range of practicable alternatives to 

be identified, not every practicable alternative. 

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EPA also disagrees with comments that the inclusion of NPS controls in the list of alternatives that could 

be considered exceeds EPA’s statutory authority under the CWA. One commenter stated that the 

proposed requirement for alternatives analysis refers directly to section 131.12(a)(2), which explicitly 

requires states to pursue “all cost-effective and reasonable best management practices for non-point 

source control.” EPA disagrees with this interpretation of language that existed prior to this final rule.

The proposal did not propose, and the final rule does not finalize, any changes to section 131.12(a)(2) 

with regard to NPS controls. Again, EPA’s preamble statements were intended solely as a list of options 

that can be considered when developing a range of practicable alternatives. The language that is 

unaffected by this final rule and which is still in effect says that when allowing degradation, “the State 

shall assure that there shall be achieved...all cost-effective and reasonable best management practices 

for nonpoint source control. This requirement is separate from the analysis of alternatives. Neither the 

revisions in today’s rule nor the preexisting requirement requires states and authorized tribes to 

establish and implement best management practices for nonpoint sources before allowing degradation 

of high quality waters. A 1994 memo explains how EPA interprets the preexisting requirement to 

“assure that there shall be achieved the highest statutory and regulatory requirements for... all costeffective and reasonable best management practices for nonpoint source controls”: 

http://water.epa.gov/scitech/swguidance/standards/upload/2006_12_01_standards_antidegmemo.pdf. 

Please see response essay 7.g.ii for additional discussion.

EPA disagrees with comments stating that EPA’s statement that “impacts beyond the direct effects on 

water quality, such as cross-media impacts” should be considered when selecting which alternative to 

implement is a mandate exceeding EPA’s CWA-granted authority. Preamble statements are not 

mandates, they offer EPA’s policy statements and recommendations to help guide states and authorized 

tribes when implementing EPA’s regulations. The preamble to the final rule puts this statement in the 

context of allowing states and authorized tribes the flexibility to balance multiple considerations, such as 

cross media impacts, when deciding whether to make a finding that a lowering of high water quality is 

necessary. Please see response essay 7.e.iv for additional discussion on selecting an alternative to 

implement.

A comment suggested that the rule require only that a state evaluate reasonable and cost-effective 

measures that would reduce or eliminate the potential degradation, rather than requiring the sort of 

“complex alternatives analysis apparently contemplated” by the rule. The final rule requirement 

requires that analyses evaluate a “range of practicable alternatives” that could prevent or lessen 

degradation. As discussed below, it does not require that every single practicable alternative must be 

considered, as long as a range is considered, nor does it require that the analyses be “complex.” In 

situations with multiple practicable alternatives, it is possible that the analysis could be limited to those 

that the entity conducting the analysis finds to be reasonable and cost-effective, provided the analysis 

considers a range of alternatives. 

EPA agrees with comments stating that the concept of “practicable” should include whether alternative 

options that would reduce degradation are available to the permit applicant and whether they are 

appropriate for the type of discharge. Based on comments received, the final preamble explains that the 

final rule contains a definition of “practicable,” and that the definition embodies a common sense 

notion of practicability – i.e., an alternative that can actually be implemented under the circumstances. 

See preamble to the final rule for more information.

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With regard to how many alternatives must be evaluated, EPA agrees with comments stating that the 

analysis of alternatives may incorporate a range of practicable options, but should not require an 

evaluation of all possible options. Commenters further said that as long as the alternatives analysis 

meets the requirement of presenting a valid range of practicable alternatives, the review process should 

not have to be restarted if a new option is identified. The final rule does not require all possible options 

be considered. In addition, the required public process and intergovernmental coordination for Tier 2 

reviews provide the opportunity for the public and stakeholders to examine the preliminary analyses 

and to raise concerns or questions about possible new options.

EPA received comments that the range of alternatives should be a range of non-degrading, minimally 

degrading and less degrading alternatives as opposed to a range of non-degrading and minimally 

degrading because there was concern that certain alternatives that were less degrading but not 

minimally degrading would not be considered. If a state or authorized tribe only had to consider 

alternatives that were non-degrading or “minimally degrading” (in the sense of “very close to nondegrading), they would not consider other alternatives that aren’t “very close to non-degrading,” but 

still would prevent some degradation. Ignoring those alternatives could lead to a finding that 

degradation is necessary, when if the other alternatives had been considered, the degradation could 

have been avoided. EPA agrees and the final rule requires the analysis to identify a “range of practicable 

alternatives that would prevent or lessen degradation,” to broaden the range of alternatives available 

for selection.

L. Relationship to the Great Lakes Initiative Rule at Part 132

EPA received comments that EPA’s preamble to the proposed rule suggests that the analysis of 

alternatives requirement is the same as required for waters covered by the Great Lakes regulation 

(40 CFR Part 132, appendix E). Commenters said that EPA cannot apply the requirements for the Great 

Lakes Waters to waters not covered by Part 132, especially those “states already implementing 

appropriate antidegradation analysis programs through their permit programs.” 

EPA agrees that it cannot apply the requirements at Part 132 to waters not covered by Part 132.

However, EPA disagrees that the proposal and final rule apply the Part 132 requirements to all waters.

EPA’s intent of the rule was not to apply the Part 132 regulations nationally. While the final rule has 

some similarities to Part 132, it is not the same and this rule does not change the applicability of Part 

132. 

The regulation at section 131.5 (a)(5) makes clear that States and authorized tribes with waters in the 

Great Lakes Basin must comply with the requirements of 131.6 and the requirements of Part 132. EPA 

did not propose or finalize any revisions to this provision.

EPA considered a comment that the concept set forth in the Great Lakes Initiative (GLI), Appendix E at 

Part 132 is more sensible than what EPA proposed for analysis of alternatives in the proposed rule at 

Part 131. The commenter pointed out that the GLI requires that states and authorized tribes use the 

alternatives analysis and other information to inform the decision on whether degradation is necessary, 

but does not specifically require selection of an alternative. Commenters seemed to interpret the lack of 

a specific requirement in Part 132 to select an alternative as meaning that states and authorized tribes 

should never be required to select an alternative, and preferred the analysis of alternatives to simply 

provide a source of information to guide agency decision-making. While it is true that the analysis 

described in Part 132 is useful to guide decision-making, PA disagrees with commenters’ interpretation 

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of the requirement in Part 132 as being limited to information that can be used as guidance at the 

state’s or authorized tribe’s discretion. If a practicable alternative is less degrading or not degrading than 

the proposed degradation, the state or authorized tribe would not have an appropriate justification for 

calling the proposed degradation “necessary.” This is true under Part 131 and under Part 131. Thus, the 

requirement at Part 132 is consistent with the requirement for analysis of alternatives in the final rule. 

The regulation at section 131.5 (a)(5) makes clear that states and authorized tribes with waters in the 

Great Lakes Basin must comply with the requirements of 131.6 and the requirements of Part 132. For 

more information, see response essay 7.k.

M. Comments on Existing Use and Implementation of Title 40 of the Code of 

Federal Regulations Section 131.12(a)(1) 

EPA received comments on existing uses and the implementation of 40 CFR section 131.12(a)(1), the 

section of antidegradation regulation dealing with existing uses protection. Although EPA did propose 

minor edits to the provisions at 131.10 regarding existing uses, those proposed changes were restricted 

in scope to two specific and limited interpretations regarding existing uses in the context of states and 

authorized tribes adopting and changing designated uses. EPA responded in essay 5.d to the comments 

received on these interpretations. EPA did not propose or solicit comments on the requirement in 

section 131.12(a)(1) regarding antidegradation “Tier 1” protection of existing uses, and the final rule 

does not alter anything in relation to that requirement. Thus, all remaining comments on existing uses 

are outside the scope of this rulemaking. 

N. Comments Questioning the Context in Which Antidegradation Reviews 

Occur

Comments stated that the proposed rule text is not clear on how or when the antidegradation “review” 

process would take place, and that states and authorized tribes have different practices for this. EPA 

recognizes that typically antidegradation review occurs in the context of a proposed activity and that a 

state or authorized tribe choosing to allow a lower water quality so the proposed activity can go 

forward. For example, a state or authorized tribe could either conduct (or have another entity conduct) 

a Tier 2 review of a proposed discharge on a high quality water for which a new NPDES permit is 

contemplated, or for a proposed increase in an existing NPDES permitted discharge. However, 

antidegradation protection is broadly applicable to water bodies, not just to specific activities causing 

changes to water quality. Thus, antidegradation review should and does occur for many other different 

types of activities including activities permitted under CWA 404 and activities subject to CWA 401 

certification. States and authorized tribes are familiar with the precise mechanics of when and exactly 

how antidegradation review takes place in their jurisdictions based on their own administrative 

processes and the circumstances of the activity that would lower water quality. EPA finds that allowing 

states and authorized tribes discretion on the mechanics of when and how antidegradation Tier 2 review 

takes place is preferable for this reason, as an appropriate exercise of cooperative federalism. In 

addition, EPA points out that antidegradation protection is not limited to Tier 2 review. Even when a Tier 

2 review is not triggered (for example, if a discharge would affect a water without Tier 2 protection), the 

federal regulation requires that states’ and authorized tribes’ antidegradation policies provide Tier 1 

protection for existing uses applies to all waters of the U.S.

A comment requested that EPA clarify that antidegradation is a WQS issue to be handled under the WQS 

program and not under the NPDES program, because there is no direct relationship between the permit 

limit setting process and the antidegradation policy. The commenter cited to 40 CFR section 122.44(d) of 

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the NPDES permitting regulation as evidence that NPDES permit limits are based on water quality 

criteria to protect designated uses, but do not include any provision where limits are based upon 

antidegradation. EPA disagrees with this characterization and is clarifying here that while states and 

authorized tribes indeed handle antidegradation in their WQS by writing antidegradation policies, 

implementation of antidegradation occurs in the context of allowing lowering of high water quality, such 

as an NPDES permit. WQS do not in and of themselves allow lowering of water quality. They are simply 

requirements articulating how states and authorized tribes will protect their water quality. When a state 

or authorized tribe is presented with decisions about allowing activities that can affect water quality, 

they look to their WQS to inform the issuance of permits or licenses allowing effects on water quality. 

Specific to the NPDES context, EPA points to 122.44(d)(1), which describes WQS and state requirements 

as any requirements in addition to or more stringent that promulgated technology based limits 

necessary to “achieve water quality standards established under section 303 of the CWA...” Further, at 

122.44(d)(1)(vii), the regulation requires that “[w]hen developing water quality-based effluent limits 

under this paragraph the permitting authority shall ensure that: (A) The level of water quality to be 

achieved by limits on point sources established under this paragraph is derived from, and complies with 

all applicable water quality standards.” While it is true that most of the provisions of 122.44(d) focus on 

details of calculating WQBELs based on criteria, antidegradation is part of the WQS established under 

section 303 of the CWA, therefore WQBELs must achieve antidegradation requirements.

EPA’s NPDES Permit Writer’s manual contains more information on the connection between 

antidegradation and writing WQBELs. 

http://water.epa.gov/polwaste/npdes/basics/NPDES-Permit-Writers-Manual.cfm

O. Comments regarding Defining “Practicable” and Other Terms Related to the 

Requirements at Section 131.12(a)(2)

EPA agrees with comments requesting that the rule define the term “practicable,” and has thus included 

a definition in the final rule.

Commenters requested that EPA define more clearly or explain by what standard various words would 

be objectively evaluated, for example “available,” “possible,” “economically viable,” “degradation,” 

“minimally degrading,” “non-degrading,” “alternatives analysis,” and “practicable alternative.” The final 

rule provides a definition for “practicable” as requested by multiple commenters, and the preamble 

discussion provides a description of what constitutes “analysis of alternatives” (called “alternatives 

analysis” in the proposed rule). Further federal definitions are unnecessary as common and plain

dictionary definitions of the words included in the final rule provide states and authorized tribes enough 

guidance to implement the regulations. States and authorized tribes have the ability to define terms in 

their own antidegradation programs as needed, provided those definitions are not inconsistent with the 

requirements of the CWA and the WQS regulation. EPA specifically disagrees with a comment 

requesting that EPA define, at a minimum, the term “degradation” as a permanent, measurable 

lowering of water quality as a result of a point source discharge. Point sources and NPS can cause 

degradation of water quality, and to define degradation as only occurring due to point sources would 

not only narrow the definition in a manner inconsistent with the CWA and the WQS regulation at 40 CFR

Part 131 because for all WQS, the standards apply to the waterbody, not the source. While commenters 

requested that EPA define more clearly “practical alternative,” the word “practical” is not included in 

the final regulation.

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Comments requested that EPA replace the word “possible” with “feasible” in the definition of 

“practicable” described in the preamble to the proposal (“the alternatives considered must be available 

for the proposed activity, technologically possible, able to be done or put into practice successfully at 

the site in question, and economically viable.”) Commenters stated that their objection was because 

some alternatives that are possible are not always feasible. EPA agrees in principle that some 

alternatives that are possible may not be feasible but disagrees that the word “possible” should be 

replaced with “feasible” in the definition of “practicable.” EPA determined that it was unnecessary to 

change “possible” to “feasible” because the terms are synonyms: Merriam-Webster defines “feasible” 

as “possible to do.” The final rule contains a definition of “practicable” similar to that proposed (see 

definition at section 131.3(n)), and does not require selection of alternatives that are not “feasible.” 

EPA disagrees with comments requesting that the definition of “practicable” include evaluation of nonwater quality impacts of each alternative to be evaluated. EPA determined that the definition of 

“practicable” should not include evaluation of non-water quality impacts because non-water quality 

impacts may be considered by the state and/or discharger when choosing among practicable 

alternatives. Therefore, EPA found it was more appropriate for “practicable” to be a broader definition 

by not including consideration of non-water quality impacts so that the decision-makers could more 

fully consider alternatives that may have non-water quality impacts in the analysis of alternatives. 

Decision-makers could then balance those considerations during the analysis, rather than potentially 

excluding those alternatives upfront (by not considering alternatives with non-water quality impacts to 

be “practicable”). As stated in the preamble, however, EPA recommends that states and authorized 

tribes consider cross-media impacts and where possible, seek alternatives that minimize degradation of 

water quality and also minimize other environmental impacts. Since it may not always be possible to 

consider alternatives that do not cause some non-water quality impacts, EPA chose not to include this 

condition on whether or not the alternative is practicable. The preamble to the final rule describes how

other environmental impacts can be considered when choosing among practicable alternatives to 

implement.

Commenters asked for clarification on what the standard would be for an “economically viable 

alternative” and asked whether an economically “viable” alternative would include not proceeding with 

a proposed project. EPA’s view is that a state or authorized tribe could consider alternatives including 

not proceeding with the project when deciding whether to allow a lowering of high water quality. EPA 

does not specifically require consideration of any particular alternative or exclude consideration of a 

particular alternative, such whether to proceed or not to proceed with an activity/project. As stated in 

the preamble to the final rule, when deciding whether to allow a lowering of high water quality, States 

and authorized tribes are responsible for making their finding based on a “reasonable, credible, and 

adequate analysis of alternatives.” Therefore it is the state or authorized tribe’s responsibility for 

ensuring they have a sufficient range of practicable alternatives to back up their finding.

EPA disagrees with comments that the term “economically viable” should be replaced with “affordable.” 

The common definitions of “affordable” include concepts like “costing little” (Merriam Webster). 

Alternatives to degradation do not always “cost little.” A common definition of “economically viable” 

would include concepts like “capable of being done in a manner that uses resources efficiently” 

(Merriam Webster). While “economically viable” and “affordable” have similar meanings, the former is 

more accurate in this context because it is important to choose alternatives that are both effective and 

take cost into consideration in relation to the project and circumstances. In response to commenters to 

make this explicit, the final rule includes a formal definition of “practicable” at section 131.3(n) that 

includes the concept of “economic viability” in addition to “technologically possible” and “able to be put 

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into practice” all of which reflect the intent that the alternatives identified must be both effective and 

affordable. 

Commenters stated that with respect to wastewater treatment technologies, an economically “viable” 

technology could be construed as one that could be implemented even if it precluded the company from 

making any reasonable profit on a venture. EPA does not construe “economically viable” in such a way. 

Common dictionary definitions for “viable” include concepts like “financially sustainable” (Merriam 

Webster) “capable of working successfully,” and “feasible” (Oxford.) EPA’s intention with the term 

“economically viable” is that the alternative can be achieved and any additional costs to implementing 

the alternative can be afforded. EPA agrees with a comment suggesting that to be economically viable, 

an alternative must be one that can be implemented at a reasonable cost to the regulated entity in light 

of that entity’s finances or without causing a substantial hardship to the entity or its customers. If a 

private entity proposes an activity that would lower water quality and conducts an analysis of 

alternatives, EPA would not expect the entity to consider alternatives that would preclude any profit.

EPA also agrees with commenters that dischargers, states and authorized tribes need not undertake 

unnecessarily costly actions that produce nominal additional environmental benefit; however the final 

rule does not require them to do so. The final rule allows the entity conducting an analysis of 

alternatives to choose among a range of practicable (definition of which includes “economically viable”) 

alternatives. When choosing among them, they may consider costs and benefits, as well as other 

considerations. They may also choose not to consider cost-benefit calculations.

EPA points out that states and authorized tribes are ultimately responsible for making the decisions 

about the alternative selected to be implemented and whether to allow degradation because a lowering 

of high water quality is necessary. They need not rely solely on an analysis presented by a private entity; 

they may consider other practicable alternatives or request analyses from different entities. Also, 

economic considerations are inherently different for publicly owned utilities, where profit is not a 

primary objective. States and authorized tribes also have the discretion to require facilities to take more 

costly actions, which may not necessarily fit a set cost-benefit ratio, as a condition of allowing 

degradation. EPA’s Interim Economic Guidance provides suggested guidelines for making decisions 

about economic considerations.

EPA considered a comment providing the example of reverse osmosis to remove miniscule 

concentrations as a non-practicable alternative. The comment stated that preparing such an alternative 

should not be imposed on the discharger performing the alternatives analysis, because it is a 

misallocation of resources. The final rule does not require analysis and identification of non-practicable 

alternatives. While reverse osmosis can be costly, in some cases it may be practicable. Reverse osmosis 

may be considered practicable in some instances, but the practicability of the technique depends on 

site-specific considerations.

EPA disagrees with a comment supporting evaluating whether an alternative is “available” or 

“technologically possible” based on what is “commonly achievable” within the industry of the regulated 

entity. There may be practicable alternatives that, while not commonly achievable within the industry of 

the regulated entity, could be achievable and implemented effectively in some cases.

EPA disagrees with a comment stating that the proposed requirement for Tier 2 analysis of “practicable” 

alternatives is in “sharp contrast” to the local control and flexibility already codified in the CWA and 

related regulations. The commenter also stated that the “practicability” standard exposed businesses to 

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a crippling lack of regulatory certainty. The commenter did not provide evidence for these assertions. 

The final rule actually preserves local control and flexibility. The structure of the federal antidegradation 

requirement specifically allows for states and authorized tribes to make the ultimate decision about 

whether to allow a lowering of high water quality based on a reasonable, credible, and adequate 

analysis of alternatives, and if so how much depending on the case specific situation. The final rule does 

not change this discretion and flexibility. 

EPA disagrees with comments requesting that the final rule remove the term “practicable” from the 

description of alternatives that must be evaluated in Tier 2 review because the word is not appropriate 

to this context. Commenters did not provide additional analysis to support that assertion. However, EPA 

found that inclusion of the term “practicable” is appropriate to achieve the goals of the Act and to 

provide clarity for decision-makers using the alternatives analysis. EPA agrees with comments that the 

term “practicable” is used elsewhere in the CWA framework, and that EPA’s definition is different from 

the definition of the same word in other EPA regulations. For this reason, the final rule defines 

“practicable” as “in the context of § 131.12(a)(2)(ii), means technologically possible, able to be put into 

practice, and economically viable.” (Section 131.3(n)). The final rule specifically explains that this 

definition is only for the context of Tier 2 review. The CWA does not require that different regulations 

define terms identically.

EPA disagrees with a suggestion to define “practicable” as wastewater treatment technology that is 

proven to be effective and implementable at the facility at a reasonable cost in light of the project 

purpose. EPA’s view is that this is an overly narrow interpretation of the range of alternatives that 

should be considered. After consideration of the comments and stakeholder input, EPA determined it 

was reasonable to structure the rule to allow consideration of alternatives beyond traditional 

wastewater treatment technology, and allows for a state or tribe to potentially consider alternatives not 

related to the project purposes (e.g., not allowing the discharge.)

A commenter specifically pointed out that the regulation at section 230 for section 404(b)(1) Guidelines 

for Specification of Disposal Sites for Dredged or Fill Material requires examination of practicable 

alternatives to the proposed discharge, and explains that “practicable” in that context means “available 

and capable of being done after taking into consideration cost, existing technology, and logistics in light 

of overall project purposes.” The commenter suggested that EPA should, at a minimum, add “in light of 

overall project purposes” to the definition of “practicable” in the final rule provision regarding Tier 2 

analysis of alternatives, since these purposes are critical to a meaningful analysis of alternatives. EPA 

disagrees that the addition of the phrase “overall project purpose” to the definition of practicable is 

necessary. The definition of practicable in section 131.3(n) is “in the context of section 131.12(a)(2)(ii), 

means technologically possible, able to be put into practice, and economically viable.” As stated in the 

preamble, this definition embodies a common sense notion of practicability (i.e., an alternative that can 

actually be implemented under the circumstances.) Thus, EPA expects that in most cases, the entity 

performing the analysis and the state would analyze practicable alternatives that take into account the 

purpose of the proposed activity; however, as stated in the preamble, it is possible for the alternatives 

analyzed to include an alternative that prevents degradation (and therefore may not be in line with the 

overall project purpose). Per section 131.12, a state or authorized tribe has the authority to decide to 

allow the lowering only if a practicable alternative that would prevent degradation of high quality 

waters is selected to be implemented, even if it means that that the overall project purposes will not be 

fulfilled.

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EPA considered the specific examples provided by commenters as evidence of difficulty in selecting and 

implementing a “practicable” alternative, such as an example of petroleum refineries where 

technologically possible alternatives for controlling inorganic constituents in effluent (for example by 

reverse osmosis) can lead to practical difficulties such as the need to dispose of salt residuals and install 

substantial tertiary treatment upstream of desalinization. Under the final rule, states and authorized 

tribes have the flexibility to decide whether to allow a lowering of high water quality and how much, 

after a public process, based on a reasonable, credible, and adequate analysis of alternatives, rather 

than being forced to require selection of the least degrading practicable alternative. This allows for 

consideration of additional factors such as whether an alternative would cause cross-media problems in 

areas other than water quality (such as excess residuals that require additional treatment). If another 

practicable alternative has fewer adverse effects, it could be selected for implementation instead.

EPA disagrees with a comment stating that the description of “practicable” in the proposal preamble is 

an inadequate basis for Tier 2 evaluations because CWA does not use the term “technologically 

possible” as the basis for setting WQBELs. Tier 2 alternatives analyses do not result directly in WQBELs; 

they are used to inform decisions about whether to allow a lowering of high water quality based on the 

alternatives to degradation that are practicable. Once an alternative has been selected for 

implementation and the state or authorized tribe has chosen to authorize the lower, the selected 

alternative may result in WQBELs more stringent than would otherwise have been allowed. However, 

identification of practicable alternatives, does not in and of itself, set WQBELs. That the CWA does not 

include the term “technologically possible” in the context of its discussion of setting WQBELs does not 

preclude EPA from requiring consideration of alternatives that are “technologically possible” when 

conducting a Tier 2 alternatives analysis. 

EPA disagrees with comments recommending that the final regulation require the evaluation of control 

alternatives to be based on the CWA factors used for best practicable control technology currently 

available (BPT), BAT, and NSPS. National regulations for industrial wastewater discharges set 

technology-based numerical effluent limitations for specific pollutants at several levels of control: BAT, 

BPT, BCT, NSPS, PSNS, or PSES. Technology based effluent limitations are based on performance of 

specific technologies, but regulations do not require use of a specific control technology. Comments

stated that NSPS level of effluent control relies on “demonstrated” technology for categories of 

dischargers with similar wastewater characteristics (a consideration established by statutory 

requirement) and reflects consideration of cost-effectiveness. Comments also discussed how evaluation 

of non-water quality impacts of treatment alternatives is enshrined in the CWA for technology based 

effluent requirements (CWA 304(b) and 306), and provided specific examples of how such 

considerations can work.

It would be inappropriate to base the WQS requirements for an analysis of alternatives, which is related 

to water quality-based requirements (from CWA section 303), on technology-based requirements (from

CWA 304 and 306) which have a fundamentally different purpose in the CWA. Technology based 

requirements are intended to provide a standardized industry expectation for what can be achieved 

based on the technology available to that industry. Water quality based requirements are intended to 

establish discharger specific expectations for pollution control in order to meet the designated use and 

criteria that a state or authorized tribe has adopted for the water being discharged into. NPDES permits 

with effluent limitations incorporate either limitations based on the industry wide effluent standards or 

limitations based on the adopted WQS, whichever are more stringent. Antidegradation is part of WQS

and is intended to implement the CWA objective to restore and maintain the chemical, physical and 

biological integrity of the nation’s waters. The requirement to evaluate a range of alternatives to 

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lowering high water quality is intended to meet this CWA goal, not to establish technology based 

requirements. In fact, some alternatives considered may not involve evaluating other technologies but 

rather other strategies. Where this is the case, limiting the alternatives considered to technology that 

correlates with technology based effluent standards would not meet the requirement to identify a range 

of alternatives that prevent or lessen degradation. Also, even in the cases where BPT, BAT and NSPS 

could potentially represent less degrading alternatives for Tier 2 review, requiring them in the federal 

WQS regulation would reduce flexibility to consider non-technology related alternatives. While 

dischargers’ analyses typically focus on treatment technologies at the facility, a state or authorized tribe 

may choose to consider other alternatives appropriate to the situation (e.g., not allowing a facility to 

expand, land application, incineration). Furthermore, levels of control expressed in effluent guidelines 

that are technology-based only exist specific to certain types of discharges. For example, NSPS exist for 

some industrial facility types, but not all industrial facilities, and not for other types of dischargers that 

may degrade high water quality (e.g., publicly owned treatment works (POTWs), discharges of dredged 

or fill material.) If the final rule on analysis of alternatives were to require evaluation of NSPS, it would 

not create a uniform expectation, and would potentially limit state and authorized tribal flexibility. For 

more information on BAT, BPT, and NSPS, see: 

http://water.epa.gov/scitech/wastetech/guide/questions_index.cfm. 

EPA’s final rule provides the flexibility for states and authorized tribes to consider practicable 

alternatives to lowering high water quality that reflect technology-based levels of effluent control 

provided those levels would prevent or lessen degradation as well as other practicable alternatives. EPA 

determined it was appropriate to maintain this flexibility in the final rule because states face a variety of 

specific circumstances when conducting antidegradation reviews, including existing facilities that may 

apply for permits to expand. Faced with these varied situations, it is imperative for states to have 

flexibility to consider alternatives that reflect technology-based levels of control without EPA specifically 

prescribing in this WQS rule which level of technology-based requirements must be met.

P. Comments about the Effect on Existing State and Authorized Tribal 

Antidegradation Programs

EPA considered comments describing the commenters’ view of how the proposed rule differs from 

current practice and currently effective regulations and policies in specific states. EPA also received a 

comment stating that a specific state’s antidegradation program is finally getting on track, but that the 

proposal, if finalized would derail it. EPA disagrees that the final rule will derail any state’s 

antidegradation program. The final rule preamble explains that while states and authorized tribes are 

subject to the requirements of today’s rule on the effective date of the rule, EPA’s expectation is that, 

where a new or revised requirement necessitates a change to state or authorized tribal WQS, such 

revisions will occur within the next triennial review that the state or authorized tribe initiates after 

publication of the rule. This allows states and authorized tribes time to evaluate, and if needed, make 

modifications to their programs. EPA intends the final rule to strengthen state antidegradation programs 

and provide additional protection for high quality waters. EPA recommends states and authorized tribes 

evaluate their program for consistency with the final regulation at Part 131.12. States and authorized 

tribes should work with their EPA Regional offices, which are available to assist states and tribes with 

any questions about the final requirements. EPA recognizes that some states and authorized tribes may 

need to revise their regulations and/or their guidance for consistency with the final rule.

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EPA disagrees with comments requesting that the EPA refrain from imposing specific requirements 

related to antidegradation analysis on states “already in compliance with these requirements” because 

more specific requirements are not warranted in states already implementing appropriate 

antidegradation analyses. It is unclear whether “these requirements” was intended to mean the 

previously existing requirements of 40 CFR 131.12, or to mean the proposed requirements that would 

have added more detail. If it means previously existing requirements, EPA disagrees because the Agency 

found that further detail in the regulation was necessary for reasons explained in the proposal 

preamble, so simply meeting the previously existing requirements did not ensure a state or authorized 

tribe is consistent with the currently applicable federal antidegradation requirements under the final 

rule. For states and authorized tribes whose programs are already consistent with the final rule 

requirements, EPA does not anticipate the need for changes to those programs. For example, states and 

authorized tribes already implementing analyses of alternatives that are consistent with the final rule’s 

requirements would not have to do anything additional to be consistent with the new requirements 

regarding analysis of alternatives.

EPA considered a comment that provided a state example of cases where the intent behind alternatives 

analysis is to determine whether a non-discharging option (such as land-application, or reuse) is viable.

The comment states that this is commonly done by looking at land application of wastewater, recycle 

and reuse options or the possibility of converting from a direct to indirect discharge. The commenter 

stated that EPA’s proposal would take this evaluation one step further, effectively requiring a permit 

applicant to demonstrate, not just that there are no non-discharging options, but also that the least 

degrading alternative has been selected. EPA disagrees. The proposal did not, and the final rule does not 

require selection of the least degrading alternative. Examining a range of practicable less degrading to 

non-degrading alternatives (such as those mentioned by the commenter), and selecting a practicable 

alternative would be consistent with the final rule.

Q. Comments regarding the Adoption of Antidegradation Implementation 

Methods and Minimum Elements of Such Methods

For comments regarding whether EPA should require adoption of statewide antidegradation 

implementation methods, and the minimum requirements content of those methods, please see 

response essays 7.f.i. and 7.g.ii.

R. Comments regarding Conducting an Analysis of Alternatives in All Cases 

versus Degradation That Goes beyond De Minimis

For comments regarding de minimis discharges, please see response essay 7.i.

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Essay 7.e.iii – Antidegradation Alternatives Analysis: Suggested

Alternatives That Should/Shouldn’t Be Considered

A. Defining “Practicable” 

The U.S. Environmental Protection Agency (EPA) agrees with comments supporting adding a definition 

of “practicable” similar to the proposal preamble description to the final rule. In light of these and other 

comments, EPA has decided to include a definition of “practicable” for the purposes of Title 40 of the 

Code of Federal Regulations (CFR) section131.12 at section 131.3(n). EPA determined that the definition 

was needed to provide clarity and consistency in the implementation of section 131.12(a)(2)(ii).

B. Comments That the Requirements Are Too Vague and Will Lead to 

Litigation

For a response to comments that the requirements are too vague and will lead to litigation, please see 

response essay 7.e.ii, section H. For a response to comments regarding defining “practicable” and other 

terms related to the requirements at section 131.12(a)(2) that commenters believe are vague and could 

also lead to litigation, please see response essay 7.e.ii, subsection O.

C. Comments Questioning the Relationship to Accommodation of Social or 

Economic Development and Evaluating Costs versus Benefits

EPA received comments and corresponding rule language suggestions where commenters stated it was 

unclear “whether (or when) States must perform both ‘a social and/or economic analysis’ and the 

alternatives analysis.” In regards to the specific wording suggestions that EPA require Tier 2 reviews to 

consider “whether the benefits of economic or social development unquestionably outweigh the costs 

of lower water quality to the affected community or surrounding area where the waters are located,” 

EPA’s regulation provides some discretion to states and authorized tribes to consider multiple factors 

when deciding whether to allow a lowering of high water quality. For a discussion on these points, 

please see the following response essays: 7.e.i subsections B and D, 7.e.ii subsections C, G, J, K, and O.

D. Comments regarding Flexibility to Consider Cross Media Impacts

For a response to these comments, please see response essay 7.e.ii subsections G, K, and O.

E. Comments regarding Opportunities to Minimize Regulatory Cost by Relying

on other Alternatives Analysis

For a response to these comments, please see response essay 7.e.ii, subsection I.

F. Comments Generally Opposing the New Requirements

EPA received a comment that generally stated that the new requirement, as proposed, would confuse, 

not clarify the analysis required under the existing rule. The commenter also stated they “also believe it 

would bring the rule into conflict with specific provisions of the Clean Water Act in a way that the 

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existing rule does not.” However, the commenter did not provide any specific evidence or examples of 

why they believe this. In response to this general comment, please see response essay 7.e.ii.

G. Comments That the Rule Should Not Require Imposition of Alternative 

Permit Limits/Enhanced Treatment Techniques

EPA received comments that the rule should not require imposition of alternative permit limits or 

enhanced treatment techniques because including them “does not foster the best use of limited 

resources to protect and improve water quality.” The final rule requires an analysis of alternatives to 

degrading high water quality as part of an antidegradation Tier 2 review. When deciding whether to 

allow a lowering of high water quality, states and authorized tribes have some flexibility to consider a 

range of practicable alternatives that would prevent or minimize degradation and to decide whether the 

lowering is “necessary.” The final rule does not require that analyses of alternatives consider enhanced 

treatment techniques. In fact, the final rule thus does not predetermine any specific alternative that 

must be implemented or require that the permit must require a specific alternative to be implemented 

or specific limits to be included. Enhanced treatment techniques, if practicable, could be among the 

range of alternatives considered, but that is not a requirement. If an analysis of alternatives results in 

identifying an enhanced treatment technique as the alternative that will be implemented, it may result 

in more stringent permit effluent limits, for example in a National Pollutant Discharge Elimination 

System (NPDES) permit. This situation is not a requirement of the final rule, but it is a possible outcome 

of Tier 2 review in a permitting context. EPA does not disagree that in some situations returning highly 

treated wastewater to surface waters could be preferable to other alternatives but that decision is left 

to the states and authorized tribes who are responsible for making the decision based on a “reasonable, 

credible, and adequate analysis of alternatives” as explained in the preamble to the final rule. 

A comment stated that when the evaluation of alternative treatment levels as part of the 

antidegradation process was advocated in the 1998 Advance Notice of Proposed Rulemaking (ANPRM), 

few numeric water quality standards (WQS) had been developed. EPA disagrees with a commenter’s 

statement that since at the present time numeric WQS have made permit limits more stringent, the 

evaluation of alternative treatment levels is an outdated, unnecessary concept. Numeric water quality 

criteria, whether they are recommended by EPA under Clean Water Act (CWA) section 304(a), 

promulgated by EPA under CWA section 303(c)(4), or adopted by states and authorized tribes and 

approved by EPA under CWA section 303(c)(2)(A) are designed to protect designated uses, representing 

the state or authorized tribe’s desired condition for its waters, consistent with the requirements of the 

CWA and EPA’s regulation at section 131. CWA section 101(a)(2) sets the goal that wherever attainable, 

water quality which “provides for the protection and propagation of fish, shellfish, and wildlife and 

provides for recreation in and on the water.” Often, states and authorized tribes are able to adopt 

designated uses to meet this goal, whereas in other instances, these uses are shown to be unattainable 

and thus another designated use is adopted. The antidegradation requirements at section 131.12(a)(2) 

are intended to protect water quality that is better than the minimum levels necessary to protect the 

uses specified in CWA section 101(a)(2); those waters are considered “high quality waters.” Therefore, 

whether or not there are advances in the availability of numeric water quality has no bearing on 

whether additional measures must be taken to protect waters that exceed the minimum level of 

water quality. 

The commenter also expressed that requiring “unnecessarily stringent limits” as part of the 

antidegradation analysis is not necessarily the best way to ensure water quality improvements. EPA 

agrees that “unnecessarily stringent limits” are not always the best way to protect waters, however the 

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final rule does not require imposition of unnecessarily stringent effluent limits in permits. As discussed 

earlier, EPA’s final rule only requires that an analysis of alternatives be conducted in order for States and 

authorized tribes have a “reasonable, credible, and adequate” basis to determine whether a lowering of 

high water quality is necessary consistent with section 131.12(a)(2). Whether more stringent limits will 

be required in a permit (or another alternative) will be required is dependent upon the alternative 

selected and the basis on which the state or authorized tribe allows the lowering of high water quality, 

and how much of a lowering it allows.

EPA agrees that there may be a situation where a discharger starts discharging with stricter limits, but 

the receiving water quality does not improve due to other sources of pollution in the watershed. The 

antidegradation requirements do not require dischargers to have stricter limits as such an outcome 

depends upon the state or authorized tribe’s decision. However, the antidegradation regulation does 

require that in order for a state or authorized tribe to make a finding to allow a lowering of high water 

quality, they must “assure that there shall be achieved the highest statutory and regulatory 

requirements for all new and existing point sources and all cost-effective and reasonable best 

management practices for nonpoint source control.” (Note that EPA’s interpretation of the latter 

requirement is that it does not require imposition of best management practices (BMPs) for nonpoint 

sources (NPS), but that any BMPs that are legally binding upon the state or authorized tribe must be 

implemented.) This requirement is intended to prevent situations where a discharger must expend 

resources to reduce the pollutant load in its effluent while other sources of pollution to the same water 

body are not meeting their requirements. It is still possible that even with all the other sources of 

pollution meeting their requirements, one discharger’s additional treatment will only cause marginal 

improvement in its effluent, and not result in a significantly ‘cleaner’ water body. The commenter also 

pointed out that it is important to consider trade-offs when determining what alternative to implement.

The final rule provides the flexibility for states and authorized tribes to choose among a range of 

practicable alternatives in order to take into account various trade-offs, such as environmental crossmedia impacts, to make a decision that lessens degradation to the overall water body (see section D of 

this essay). The entity conducting a Tier 2 review can also consider costs and cost-effectiveness when 

choosing among the alternatives, please see section C of this essay. 

H. If More Stringent Effluent Limitations Are Necessary, Impose Requirements 

in the National Pollutant Discharge Elimination System Regulation

EPA disagrees with a comment stating that if EPA believes that more stringent effluent limitations are 

necessary in certain circumstances and for certain waters, then the appropriate way to address the issue 

is to propose specific requirements in the federal NPDES regulation at 40 CFR Part 122, not through a 

vague requirement imposed indirectly in the federal WQS regulation.

As discussed in section G, the antidegradation requirements do not require dischargers to have stricter 

limits as such an outcome depends upon the state or authorized tribe’s decision. The federal 

antidegradation regulation intentionally leaves decision-making to states and authorized tribes 

regarding whether to allow a lowering of high water quality and if so, how much lowering to allow when 

the water quality is better than necessary to protect the uses specified in CWA section 101(a)(2) (see 

section G for additional discussion). Antidegradation protection consistent with 131.12(a)(2) (i.e., Tier 2 

protection) implements the broader goal of the CWA, to restore and maintain the chemical, physical, 

and biological integrity of the nation’s waters. The CWA does not require that high water quality (i.e., 

water quality that is better than necessary to protect the CWA goal uses) must be maintained and 

protected in all waters of the U.S. under all circumstances. Therefore, the WQS regulation reflects the 

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fact that states and authorized tribes have the authority to make decisions, in consultation with their 

public, on whether to allow degradation of their high water quality, and how much, on a case-by-case 

basis. This means that they may require more stringent water quality-based effluent limits (WQBELs) or 

other conditions on permits on a case-by-case basis, depending on the outcome of the Tier 2 review. Of 

course, any degradation that states and authorized tribes allow may not result in nonattainment of the 

state/authorized tribally adopted designated uses and criteria.

In addition, WQS, including antidegradation protection, are broadly applicable to waters of the U.S. and 

are not limited in their application to the NPDES permitting context or any other particular source of 

pollution. Therefore, EPA is not saying with this rulemaking that “more stringent effluent limitations are 

necessary in certain circumstances and for certain waters” as the commenter suggests. Rather, EPA’s 

requirement means that any decisions must be based on a “reasonable, credible, and adequate analysis 

of alternatives” before deciding that any lowering of high water quality is necessary. Any resulting 

actions necessary to implement antidegradation protection can be implemented, as necessary, through 

any particular program such as NPDES permitting, 404 permits and can even lead to conditions on 401 

certifications for federal activities that will affect water quality.

I. Comments That the 1995 Draft Interim Economic Guidance Contradicts the 

Regulation

EPA disagrees with a comment that the proposed regulation contradicted EPA’s 1995 Draft Interim 

Economic Guidance for Water Quality Standards, which provides methods for determining if the 

economic development associated with a proposed lowering of water quality is “important” (one 

required aspect of a state’s or authorized tribe’s Tier 2 finding to allow degradation.) The commenter 

stated that the interim guidance seems to be at odds with imposing alternative permit limits derived 

through consideration of enhanced treatment techniques as part of a Tier 2 analysis of alternatives, 

because the memo does not anticipate requiring any practicable treatment alternative. The commenter 

cited the transmission memo statement that “[t]he economic impacts to be considered are those that 

result from treatment beyond that required by technology-based regulations [secondary treatment]. All 

economic analyses of water quality standards should address only the cost of improving the water to 

meet water quality standards or the cost of maintaining water quality in high-quality waters.” The 

interim guidance indeed does limit analysis to only the cost of improving the water to meet WQS or to 

maintain water quality in high quality waters. If a Tier 2 analysis of alternatives, as required by the final 

rule, results in identification of a practicable alternative that would lessen or prevent lowering of water 

quality, the purpose of imposing that alternative would be in order to maintain water quality in high 

quality waters. This is consistent with the interim guidance.

J. Comments regarding Specific State Permitting Processes and Whether That 

Negates the Need for Antidegradation Processes

EPA considered comments that provided a detailed description of how one specific state issues its 

permits as part of its reasoning that an analysis of alternatives is not necessary. However, as noted 

above, even if permit limits are more stringent than in the past, the antidegradation regulations at 

section 131.12(a)(2) are meant to protect waters that exceed the levels necessary to support the 

propagation of fish, shellfish, wildlife, and recreation in and on the water. The antidegradation 

provisions protect high water quality while the numeric WQS protect the minimum water quality to 

meet the designated uses. EPA is willing to work with states and authorized tribes as they are deciding 

the best way to implement EPA’s final rules.

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K. Comments regarding Minimum Elements

For comments regarding why the minimum elements of antidegradation implementation methods 

discussed in the proposal are not included in regulation, please see response essay 7.g.i.

L. Comments on the Relationship of Antidegradation Requirements to the 

Great Lakes Initiative and Part 132

For comments involving the antidegradation requirements included in the Great Lakes Water Quality 

Initiative at 40 CFR Part 132, please see response essay 7.e.ii, subsection L and 7.k.

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Essay 7.e.iv – Antidegradation Alternatives Analysis: Selecting an

Alternative

A. Comments on Whether EPA Should or Should Not Require Selection of the 

Least Degrading/Minimally Degrading Alternative

The U.S. Environmental Protection Agency (EPA) received comments stating that the regulation should 

require states and authorized tribes to select the non-degrading or least-degrading alternative or the 

least degrading practicable alternative for implementation. Commenters stated that such restriction is 

essential because degradation is not “necessary” if there is a non-degrading or least degrading 

alternative (or least degrading practicable alternative) available. Other commenters requested that the 

regulation allow flexibility for states and authorized tribes to choose practicable alternatives that might 

not be the ‘nondegrading’ or ‘least degrading’ to ensure they can make decisions that truly result in less 

environmental degradation. Some cited to consideration of other environmental effects. For example, 

an alternative that is less degrading to water quality might be more degrading to air quality. As another 

example, wastewater recycling may not be the least degrading alternative for the project in question but 

provides water quality or water supply benefits elsewhere. Finally, commenters asserted that there may 

also be geographic considerations that could come into play when considering alternatives that require 

shifting the degradation to another area. 

EPA considered the comments, including those providing examples of hypothetical situations to 

illustrate potential consequences of today’s rule. EPA agrees that states should not be limited to 

choosing the least degrading alternative from a list of “viable” treatment/control options without some 

flexibility. The final rule allows for this flexibility, because it does not require choosing the least 

degrading practicable alternative but rather requires the selection of an alternative from a range of 

practicable alternatives that would prevent or lessen degradation associated with the activity. While

non-degrading or least degrading practicable alternatives are preferable in terms of preserving water 

quality, the reality is that states and authorized tribes must contend with competing environmental 

priorities. EPA chose not to require implementation of the least degrading practicable alternative in the 

final rule to allow states and authorized tribes the flexibility to balance multiple considerations. Some 

alternatives to lowering water quality can have negative environmental impacts in other media (e.g., air, 

land). For example, incinerating pollutants rather than discharging the pollutants to surface waters could 

adversely impact air quality and energy use, and land application of pollutants could have adverse 

terrestrial impacts. In other situations, use of sustainable or “green” technologies can afford 

environmental benefits other than benefits to water quality. EPA recommends that states and 

authorized tribes consider cross-media impacts and, where possible, seek alternatives that minimize 

degradation of water quality while also minimizing other environmental impacts.

Some comments suggested that the regulation should explicitly instruct states and authorized tribes to 

consider adverse environmental impacts associated with the alternative and others stated that the 

proposal instructs states and authorized tribes to consider cross-media impacts. While EPA agrees that 

examining alternatives to water quality degradation in the context of a broader view of environmental 

impacts can result in environmentally beneficial decisions, the final water quality standards (WQS) 

regulation only addresses state and authorized tribal decisions about water quality. The final rule does 

not require states or authorized tribes to consider cross-media impacts because EPA views this as an 

area appropriate for state and authorized tribal discretion in managing their multiple environmental 

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programs. EPA recognizes, however, that states and authorized tribes may need or want to consider 

cross-media impacts, so the final rule provides flexibility for that consideration without creating a 

requirement.

EPA also agrees with comments stating that the regulation should allow states and authorized tribes, 

when reviewing analyses of alternatives, to consider cost-effectiveness in addition to watershed or 

cross-media issues in alternative selection. EPA agrees that states and authorized tribes can consider 

holistic approaches, such as installing nonpoint source (NPS) controls throughout a watershed to 

achieve overall water quality improvement, rather than focusing only on a single discharge point, 

particularly if this will achieve more water quality improvement for the expense. EPA agrees that in 

some situations when a less-degrading treatment technology or other alternative exists, it may provide 

less additional water quality benefit for the additional expense than would pursuing more holistic 

approaches to water quality improvements.

For the same reasons discussed thus far, EPA’s final rule does not require selection of the minimally 

degrading practicable alternative. States and authorized tribes will have the flexibility to choose among 

the range of non- and less degrading alternatives, considering costs and other environmental impacts

and other factors such as site-specific circumstances of the project.

A comment suggested that the regulation should require that states and authorized tribes must choose 

a practicable alternative unless EPA has approved the use of other scientific, cost-effectiveness, or 

holistic environmental factors in the state’s or authorized tribe’s antidegradation implementation 

methods. EPA agrees in principle that states and authorized tribes should include descriptions of the 

considerations they will use in Tier 2 review decisions. EPA also agrees that states and authorized tribes 

should have flexibility to consider other factors in selecting an alternative to be implemented, and the 

final rule allows for this flexibility. However, the final rule does not require that states and authorized 

tribes adopt their implementation methods into rule, so EPA will not necessarily be approving or 

disapproving state/authorized tribal such methods (unless the state or authorized tribe chooses to 

adopt antidegradation implementation methods into rule). Such descriptions of the state/authorized 

tribal considerations are important so that the public can understand the decision making process. The 

purposes of the antidegradation requirements will be met if a practicable alternative is chosen that 

lessens degradation associated with the proposed activity and the state conducts the social and economic 

analysis (EA) and concludes that in light of the analyses, the lowering of water quality is necessary. EPA 

believes it is appropriate to provide discretion to states and authorized tribes to determine which 

practicable alternative from the range of practicable alternatives required by section 131.12(a)(2) must be 

selected in order to make a finding that lowering of high water quality is “necessary.” 

Some commenters requested that the rule explicitly not preclude state flexibility to consider cost and 

overall impact on the environment in the high quality waters decision process. While EPA agrees in 

principle that states and authorized tribes have flexibility to consider such factors when choosing a 

practicable alternative (i.e., from the “range of practicable alternatives that would prevent or lessen the

degradation associated with the proposed activities”), EPA disagrees that it is appropriate to describe 

the flexibility regarding the factors the state or authorized tribe should consider in the regulatory text. 

The lack of prescription on this point in regulatory text means that flexibilities are possible. Flexibilities 

in this case are best described outside of rule. The final rule is, however, explicit that there is flexibility 

to choose among the practicable alternatives identified in the analysis. EPA will consider whether and 

how to revise future guidance to provide examples of the considerations that may influence the 

selection of the alternative.

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For comments that requiring anything other than the least degrading practicable alternative to be 

selected is inconsistent with Clean Water Act (CWA) and existing regulation, please see response essay 

7.e.ii, section C.

B. Comments regarding State/Tribal Flexibility and Consideration of CostEffectiveness

A comment stated that “the CWA does not authorize EPA or states to require implementation of 

alternatives based on feasibility or cost; such alternatives must be based on environmental need. In 

other words, requiring implementation of an alternative measure simply because it is possible to do so 

goes beyond what the Clean Water Act authorizes.” The final rule allows states and authorized tribes to 

take into account cost and environmental impacts when deciding which of the practicable alternatives

(i.e., from the “range of practicable alternatives that would prevent or lessen the degradation associated 

with the proposed activities”) identified should be implemented in order to authorize a lowering of high 

water quality. The rule does not require implementation of an alternative “simply because it is possible 

to do so.” States, authorized tribes have flexibility in determining whether to allow a lowering of water 

quality which is consistent with the agency’s longstanding policy. Since 1983, the Tier 2 regulation has 

reflected the policy that for high quality waters, before allowing any lowering of water quality, the state 

or authorized tribe must find that allowing lower water quality is necessary to accommodate important 

economic and social development in the area in which the waters are located. EPA agrees that criteria 

and water quality-based effluent limits (WQBELs) are to be based on science, what is necessary to meet 

uses or applicable standards, without regard to costs. By contrast, the lowering contemplated in a Tier 2 

antidegradation analysis is about a lowering that will still meet water quality criteria protective of CWA 

101(a)(2) uses. The CWA does not preclude EPA from allowing a state to consider economic factors 

when making a finding to allow a lowering of water quality in a water that will, even after the lowering, 

still meet applicable criteria to protect CWA 101(a)(2) uses. In fact, the Supreme Court has held in two 

relevant recent decisions that where a statute does not prohibit consideration of certain factors then 

the agency has authority to consider that factor. See Entergy Corp. v. Riverkeeper Inc., 556 U.S. 208, 222 

(2009) (“[the statute] is unencumbered by specified statutory factors of the sort provided for those 

other two tests, which omission can reasonably be interpreted to suggest that the EPA is accorded 

greater discretion in determining its precise content. . . . It is eminently reasonable to conclude that 

Section 1326(b)’s silence is meant to convey nothing more than a refusal to tie the agency’s hands as to 

whether cost-benefit analysis should be used, and if so to what degree.”) See also Michigan v. EPA, 192 

L.Ed.2d 674, 682-83 (2015) “Consideration of cost reflects the understanding that reasonable regulation 

ordinarily requires paying attention to the advantages and the disadvantages of agency decisions. It also 

reflects the reality that ‘too much wasteful expenditure devoted to one problem may well mean 

considerably fewer resources available to deal effectively with other (perhaps more serious) problems’”

(citing Entergy Corp. v. Riverkeeper). For a full discussion on the flexibility states and authorized tribes 

have in regards to the requirements at section 131.12(a)(2)(ii), please see response essay 7.e.ii, 

section G. For a discussion on how costs and economics can be considered in the process, please see 

response essay 7.e.ii, section J.

C. Comments Questioning What Alternatives Must Be Considered

EPA disagrees with comments stating that states and authorized tribes should analyze all non-degrading 

and least-degrading options before concluding that lowering water quality is acceptable. The final rule 

balances the need for a credible finding that lowering of water quality is “necessary to accommodate 

important economic or social development” with the need to preserve state and authorized tribal 

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flexibility in decision-making and the need to consider practicability. The final rule requires that the 

analysis of alternatives evaluate a range of practicable alternatives (as opposed to all alternatives) that 

would prevent or lessen the degradation associated with the proposed activity.

Commenters stated that the rule must require full evaluation of the feasibility of the alternatives 

before determining that degradation is necessary. While the final rule does not explicitly require “full 

evaluation of the feasibility of alternatives,” EPA agrees that evaluation of the feasibility of the 

alternatives is an important step and the final rule’s use of the word “practicable” is intended to 

encompass feasibility, which the agency views as a synonym of “practicability.” In order to consider a 

range of “practicable” alternatives, the entity conducting the analysis of alternatives must have 

information on feasibility.

For additional discussion on the requirements for the range of practicable alternatives, please see 

response essay 7.e.ii, section K.

A comment requested that EPA acknowledge in regulation that under some circumstances, returning 

highly treated wastewater flows to surface waters best meets the goal of supporting the protection of 

fish, shellfish, wildlife, and recreation in and on water. As discussed in response essay 7.e.ii and earlier in 

this essay, EPA agrees that states and authorized tribes have the flexibility to consider other 

environmental impacts when deciding whether and how much lowering of high water quality to 

authorize. Response essay 7.e.ii also explains that the final rule does not dictate exactly how the analysis 

of alternatives must be conducted nor does it specify which alterative must be chosen. Rather, it 

provides regulatory language to make clear that (1) an analysis of alternatives must be done, (2) the 

alternatives must be a range of practicable alternatives, and (3) a state or authorized tribe shall only find 

that a lowering is necessary if one such practicable alternative is selected. How the analysis is conducted 

is up to the entity conducting the analysis, which alternative is selected from the list of practicable 

alternatives is up to the selector. But, EPA’s regulations provide clarity on what must occur in order for 

the State’s or authorized tribe’s finding to be consistent with EPA’s regulations and thus with the CWA. 

Therefore, analyses of alternatives can include other alternatives such as water conservation, control of 

infiltration/inflow, and recycling or reuse. EPA expects that each alternatives analysis will consider 

alternatives appropriate to the situation in question.

Some commenters expressed concern with EPA’s references to “economic viability” for alternatives and 

thought that such a term does not provide assurances that benefits and costs will be fairly balanced 

when states are developing ranges of alternatives. EPA agrees because the intent of the regulation is not 

to provide guarantees for any decision. As discussed in response essay 7.e.ii, section O, states and 

authorized tribes have considerable discretion to determine whether or not to make a finding that 

lowering high water quality is “necessary.” EPA’s regulations are only intended to be clear what must be 

done to be consistent with the CWA. Response essay 7.e.ii, section O discusses how certain terms, such 

as “economic viability” play a role in these state/authorized tribal decisions and why EPA chose not to 

provide explicit regulatory definitions of these terms. EPA considered commenter concerns that any 

time flexibility is allowed by a regulation, legal challenges may result. EPA’s view is that the final 

regulation provides the right balance of limitations and flexibilities in the area of Tier 2 analysis of 

alternatives because it provides a basic framework for the characteristics of the alternatives that must 

be considered while not prescribing specific alternatives and allowing states and authorized tribes the 

ability to choose the alternative for implementation. For additional discussion on comments concerned 

with legal vulnerability, please see response essay 7.e.ii, section H. Please also see response essay 7.e.ii, 

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section K for an explanation that EPA’s final rule does not require an evaluation and identification of ALL 

practicable alternatives, but a range. 

D. Comments regarding Using the Term “Less” Rather than “Minimally” 

EPA agrees with comments suggesting replacing the word “minimally” in the proposed requirement that 

an analysis of alternatives consider a “range of non-degrading and minimally degrading practicable 

alternatives” with the word “less.” Commenters pointed out that considering only “minimally” 

degrading alternatives might rule out consideration of alternatives that might result in some 

degradation from ambient water quality, but more than would be considered “minimal.” EPA revised 

the final rule accordingly and thus the final regulatory language requires the analysis to consider a 

“range of practicable alternatives that would prevent or lessen the degradation associated with the 

proposed activity.” 

A comment pointed out that the preamble to the proposal did not define “minimally,” leading to 

possible confusion. The final rule does not use the word “minimally” so that term is not defined in the 

rule or preamble.

E. Comments regarding the Use of the Word “Practicable” 

EPA disagrees with a comment requesting deletion of the word “practicable” in the proposed 

description of the range of alternatives to be considered in analyses of alternatives. The final rule uses 

the word “practicable” similarly to the proposed rule. The final rule states that “[t]he analysis of 

alternatives shall evaluate a range of practicable alternatives that would prevent or lessen the 

degradation associated with the proposed activity.” The commenter suggested that it may not be 

possible to determine if an alternative is practicable without further consideration. EPA’s view is that 

this is not always the case, as states and authorized tribes can obtain information on common 

practicable alternatives appropriate for a proposed activity from additional existing resources (e.g.,

EPA’s Municipal Technologies website, which presents technology fact sheets to assist in the evaluation 

of different technologies for wastewater at http://water.epa.gov/scitech/wastetech/mtb_index.cfm.) In 

the case of activities for which less information is available to assist with identifying practicability 

upfront, states and authorized tribes would need to evaluate that early on as part of the Tier 2 review, 

when identifying alternatives for the analysis of alternatives.

A comment stated that the proposal was not clear about whether an analysis of alternatives could 

consider the cost-effectiveness of additional treatment/controls in the process of deciding which 

alternatives are “practicable.” The preamble to the proposal explained that “practicable” included the 

concept of “economically viable.” The commenter explained that while an alternative could be 

“economically viable,” the cost to install it might be excessive when compared to the 

increment/amount/degree of water quality protections that may result. The final rule requires that “The 

analysis of alternatives shall evaluate a range of practicable alternatives that would prevent or lessen 

the degradation associated with the proposed activity.” The final rule defines “practicable” for the 

purposes of antidegradation at section 131.3(n) as “technologically possible, able to be put into practice, 

and economically viable.” Please see response essay 7.e.ii, section O for additional discussion on the 

term “practicable.” If an analysis identifies more than one practicable alternative, the entity conducting 

the analysis could consider the cost-effectiveness of each of those alternatives in choosing one to 

implement.

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F. Comments That the State or Authorized Tribe Itself Need Not Conduct the 

Analysis

Commenters expressed concern that the proposed rule language implied that states and authorized 

tribes must perform the analysis of alternatives themselves, when other entities may be best positioned 

to analyze the alternatives. Please see response essay 7.e.ii, section D for a response to these 

comments. The final rule language allows states and authorized tribes to rely on analyses prepared by 

third parties (e.g., a permit applicant). This preserves appropriate flexibility for states’ and authorized 

tribes’ decision-makers, and can bring additional resources and expertise to the analysis. States and 

authorized tribes remain ultimately responsible for making findings to allow degradation and for basing 

their decisions on adequate analyses. If the state or authorized tribe deems an initial analysis of 

alternatives insufficient to support a finding that a lowering of high water quality is “necessary,” it can 

request additional analyses of alternatives from the permit applicant or other entities. A state or 

authorized tribe can also obtain information on common practicable alternatives appropriate for a 

proposed activity from additional existing resources.

G. What Exactly Is the Finding of Necessity For? 

Commenters requested clarity on which evaluation EPA was proposing that states follow when deciding 

whether to allow lowering of high water quality through the alternatives analysis: “as necessary to 

accommodate important economic or social development,” or “as necessary to accomplish the 

proposed activity?” The requirement in the regulation at section 131.12(a)(2), and that is unchanged by 

this final rule, is that the ultimate finding to allow degradation is based on whether the lowering is 

“necessary to accommodate important economic or social development,” not simply whether 

degradation is necessary to accomplish the proposed activity. There is no presumption that the activity 

must be allowed. The preamble to the final rule explains that states’ and authorized tribes’ finding to 

allow a lowering of high water quality depends on both an analysis of alternatives and an analysis on the 

importance of the degradation related to economic or social development. Today’s rule preserves 

states’ and authorized tribes’ discretion to decide the order in which they satisfy these requirements. A 

state or authorized tribe can choose to first review an analysis of economic or social development. If it 

finds that the proposed lowering of water quality would accommodate important economic or social 

development, it can then require an analysis of alternatives to see if the lowering could be prevented or 

lessened. If, on the other hand, a state or authorized tribe finds that the proposed lowering of water 

quality would not accommodate important economic or social development, it could choose to disallow 

lowering of water quality and terminate the Tier 2 review without ever requiring an analysis of 

alternatives. Similarly, a state or authorized tribe could first choose to require an analysis of alternatives 

and then examine an analysis of economic or social development. In this case, if a non-degrading 

alternative is selected for implementation, the state or authorized tribe does not need to proceed with 

an analysis of economic or social development since there is no “lowering” to authorize. 

H. Comments That an Alternatives Analysis Prepared for the National 

Environmental Policy Act Etc. Should Suffice

For a response to comments questioning the relationship of antidegradation alternatives analysis and 

NEPA, 404, and 401 certifications, please see response essay 7.e.ii, section I.

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I. Comments Insisting That EPA Not Allow Degradation for Normal Sprawl and 

Growth

EPA disagrees with comments stating that EPA should better define the analysis of alternatives such that 

a state is not allowed to lower water quality for normal sprawl and growth but rather that states be 

required to address those issues before water quality is threatened. EPA does not have the authority to 

regulate states’ and authorized tribes’ growth through the WQS regulation. As articulated in the 1994 

WQS Handbook, antidegradation is not a “no growth” rule and was never designed or intended to be 

such. It is a policy that allows public decisions to be made on important environmental actions. Where a 

State or authorized tribe intends to provide for development, it may decide, after satisfying the 

requirements for intergovernmental coordination and public participation, that some lowering of water 

quality in “high-quality waters” is necessary to accommodate important economic or social 

development. Any such lower water quality must protect existing uses fully, and the State must assure 

that the highest statutory and regulatory requirement for all new and existing point sources and all costeffective and reasonable best management practices (BMPs) for NPS control are being achieved on the 

water body.

J. Steps of Tier 2 Review

A comment requested EPA clarify the requirement of (a) the socio-economic review, (b) the assurance 

of the protection of existing uses, (c) the assurance all requirements for new and existing point sources 

are met and (d) that all cost-effective and reasonable BMPs for NPS control have been applied before 

degradation is allowed. EPA confirms here that these elements are all indeed required aspects of Tier 2 

review to be completed before allowing degradation of high quality water. The final rule is intended to 

strengthen and clarify what is needed in order for states and authorized tribes to find that a lowering is 

necessary. As discussed in section G of this essay, this finding is based both on whether the lowering is 

“necessary” and whether the lowering would accommodate important economic or social development.

Please see the preamble to the final rule and discussion throughout the comment response document

for additional discussion and clarification.

K. Comments regarding Whether Tier 2 Reviews Required on Waters with Use 

Attainability Analyses

Commenters said that the proposal seemed to require states and authorized tribes to conduct Tier 2 

reviews on waters with use attainability analyses (UAAs) showing that a 101(a)(2) use is not attainable, 

and questioned whether that was EPA’s intent. Whether or not a UAA has been conducted for a water 

body is not relevant for states and authorized tribes that identify waters for Tier 2 protection on a 

parameter-by-parameter basis. In those cases, when determining whether a Tier 2 review is needed, 

tier 2 protection is provided for all parameters exceeding levels necessary to support CWA 101(a)(2) 

uses, regardless of what the designated uses are. Please see 78 FR 54527 (September 4, 2013) for 

additional discussion on parameter-by-parameter approach and how it differs from a water body-bywater body approach.

For states and authorized tribes that identify waters for Tier 2 protection on a water body-by-water 

body basis, whether a water body has had a 101(a)(2) use or uses removed via a UAA is one factor that 

can be considered in deciding whether or not to classify the water as a high quality water to receive Tier 

2 protection. But, it would not be consistent with the final rule to exclude a water from Tier 2 protection 

solely because a UAA has been conducted to justify that one of the uses specified in CWA section 

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101(a)(2) is not attainable. A state or authorized tribe could conduct a UAA to demonstrate that an 

aquatic life use consistent with the CWA 101(a)(2) is not attainable, and EPA could approve it. However, 

a recreational use could still be attainable and the water could still have water quality that exceeds 

levels necessary to support recreational uses consistent with CWA section 101(a)(2). The preamble to 

the final rule says “Thus, when considering whether to exclude waters from Tier 2 protection, states and 

authorized tribes must consider the overall quality of the water rather than whether water quality is 

better than necessary for individual chemical, physical, and biological parameters to support all the uses 

specified in CWA section 101(a)(2). The rule provides for a decision-making process where states and 

authorized tribes consider water quality and reasons to protect water quality more broadly.” EPA’s 

preamble also says, “where water quality is not better than necessary to support all of the uses specified 

in CWA section 101(a)(2), the final rule does not require states and authorized tribes to provide Tier 2 

protection for the water body.” Whether a UAA has been done and EPA has approved the associated 

use change can inform whether water quality is better than necessary to support all of the uses 

specified in CWA section 101(a)(2). While the rule allows states and authorized tribes discretion, states’ 

and authorized tribes’ decisions about whether or not to provide Tier 2 protection must be based on 

something more than solely the fact that a water is not exceeding levels necessary to support all of the 

CWA 101(a)(2) uses, and are subject to public participation. Therefore, under the final rule, if a UAA 

demonstrates that one of the 101(a)(2) uses is unattainable (and consequently, the water is “not 

exceeding levels necessary to support all of the CWA 101(a)(2) uses”), this UAA demonstration cannot 

be the sole reason for not conducting a Tier 2 review.

L. Comments on De Minimis Exemptions

For a response to comments regarding de minimis exemptions, please see response essay 7.i.

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Essay 7.f – Antidegradation: Implementation Methods

No comments are assigned to this issue category, and thus no response is necessary.

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Essay 7.f.i – Antidegradation Implementation Methods: Transparency 

and Adoption

A. Comments Opposing EPA Requiring Adoption of Antidegradation 

Implementation Methods

The U.S. Environmental Protection Agency (EPA) received many comments in response to the question 

in the proposal preamble of whether EPA should require states and authorized tribes to adopt 

antidegradation implementation methods as legally binding. Some of these commenters preferred 

allowing states and authorized tribes to have their implementation methods in guidance. Some 

supported allowing them to develop methods under a separate rulemaking, apart from water quality 

standards (WQS). Some said that at most EPA should provide that States and authorized tribes may, but 

are not required to, adopt antidegradation implementation methods as WQS. The final rule requires 

that states and authorized tribes: “shall develop methods for implementing the antidegradation policy 

that are, at a minimum, consistent with the State’s policy and with paragraph (a) of this section. The 

State shall provide an opportunity for public involvement during the development and any subsequent 

revisions of the implementation methods, and shall make the methods available to the public.” After 

considering the comments and stakeholder input, EPA determined that it is not appropriate at this time 

to require states and authorized tribes to include antidegradation implementation methods in legally 

binding form for the following reasons.

First and foremost, EPA found that EPA could accomplish the goals of improving public transparency 

and enhancing public involvement and improving accountability in several other ways. EPA added a 

requirement to the final rule that states and authorized tribes must involve the public in development 

and revision of implementation methods. This provides for enhanced public involvement. Unlike the 

proposed rule, which included the new requirements for identifying waters for Tier 2 protection and 

analysis of alternatives as aspects of implementation methods, the final rule requires states’ and 

authorized tribes’ antidegradation policies (which are legally binding state and authorized tribal 

provisions subject to public participation) to be consistent with the new requirements related to 

identifying waters for Tier 2 protection and the new requirements for analysis of alternatives. As 

described in the preamble to the final rule, since states and authorized tribes must provide for public 

participation on their antidegradation policies, placing these requirements in their antidegradation 

policies increases accountability and transparency. Thus, states and authorized tribes can still provide 

this accountability and transparency for identification of waters for Tier 2 protection without a 

requirement to adopt implementation methods.

Secondly, EPA agreed with some of the commenters’ concerns regarding potential consequences of 

requiring adoption of implementation methods. EPA found that specific state examples describing the 

burden of adopting implementation methods were compelling, because when a state or authorized 

tribe goes to adopt methods that they have previously invested time and resources into developing as 

guidance into regulation, the WQS rulemaking can become more complicated and states and authorized 

tribes can incur difficulties in going through the legislative process. Further, adding implementation 

methods to the state’s or authorized tribe’s WQS requires additional time and resources in the triennial 

review process, which may delay revisions to those methods and the state’s or authorized tribe’s entire 

WQS triennial review package. All of these factors may increase the burden on some states and 

authorized tribes that could impede their ability to focus resources on actually implementing the 

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regulation. Also, some states and authorized tribes have long, detailed antidegradation implementation 

methods documents that include items not well-suited to adoption in rule (e.g., descriptions, examples), 

and items that do not directly relate to the actual protection provided by antidegradation (e.g., 

mechanics of the transmission of paperwork internal to the state or authorized tribe). EPA’s view is that 

it is not essential that these types of items be included in state and authorized tribal regulations if they 

do not directly affect how antidegradation protection will be provided. EPA also found that for some 

states and authorized tribes, incorporation of implementation methods into WQS can impede 

innovation and the ability to adapt appropriately to site-specific or novel situations, because of the 

difficulty of going through the required administrative process to change methods once they are 

adopted as regulation.

EPA disagrees with comments saying that there is no confusion as to whether implementation of 

implementation methods must be required because in the commenters’ view, the previous regulation 

already required state and authorized tribal implementation methods to be adopted. The fact that EPA 

received comments indicating an incorrect understanding of the previous regulation’s requirement 

(which was not to adopt implementation methods, but to identify them, either in rule or in guidance) 

means that there was confusion, and that clarification in the final rule was needed. This is one reason 

that EPA finalized changes to the requirement regarding implementation methods.

EPA received comments incorrectly stating that the previously existing provision on general policies at 

Title 40 of the Code of Federal Regulations (CFR) section 131.13 already required that implementation 

methods be subject to EPA review and approval under Clean Water Act (CWA) section 303(c). EPA 

disagrees. The previously existing provision at section 131.13 addressed general policies that are 

discretionary for states and authorized tribes, such as variances, low flow provisions, and mixing zones. 

This means, for these topics, states and authorized tribes have discretion as to whether to adopt a 

provision, but if they choose to adopt provisions, such provisions are subject to EPA review and approval 

under 303(c). This provision is not applicable to antidegradation implementation methods, because 

those are not discretionary, and are addressed under section 131.12. The previous version of section

131.13 required that states and authorized tribes identify implementation methods, but did not require 

that they adopt such methods. If a state’s or authorized tribe chose to have methods that are not legally 

binding, they are not subject to EPA review and approval under 303(c).

EPA received comments incorrectly stating that 131.5(a)(3) would require, for the first time, that EPA 

review state antidegradation implementation methods if the state or authorized tribe has “chosen to 

formally adopt implementation methods as water quality standards,” and stated that this would be an 

incentive for states to accomplish implementation through state guidance and policy documents. The 

final rule at 131.5(a)(3) does not expand EPA’s authority. Previously, if a state or authorized tribe 

adopted implementation methods as legally binding, EPA had the authority to act on such methods 

under CWA 303(c). EPA’s authority for this position is discussed in EPA’s 2012 frequently asked 

questions (FAQ) titled “What is a New or Revised WQS under CWA section 303(c)(3)” found at 

http://water.epa.gov/scitech/swguidance/standards/cwa303faq.cfm. The final rule provides a 

clarification in the regulation of EPA’s longstanding position on the Agency’s authority. As explained, 

where states and authorized tribes adopt legally binding antidegradation implementation methods, EPA 

continues to have the authority to review and approve/disapprove such methods.

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B. Comments That Support Requiring Adoption of Antidegradation 

Implementation Methods

EPA also received comments supporting a requirement for states and authorized tribes to adopt their 

implementation methods as legally binding. Some commenters also supported clarifying that 

implementation methods are part of the minimum requirements for a state or authorized tribal WQS 

submission to EPA, and that implementation methods should be included in triennial reviews. Some 

commented that allowing states to continue keeping implementation methods outside of legally binding 

rules would not be of value to incorporate into the regulation. Commenters supported adoption of 

implementation methods for a variety of reasons. EPA lists the commenters’ points and EPA’s responses 

here. Despite comments that EPA’s previous regulation requiring the identification of implementation 

regulations has been ineffective, EPA disagrees that it must require adoption of antidegradation 

implementation methods in order to accomplish its goal for effective antidegradation implementation 

and thus the final rule does not require adoption of antidegradation implementation methods.

Commenters expressed concern that the proposal removed an existing requirement for adoption of 

implementation methods as WQS, and cited to the 1994 WQS Handbook at 4.1: “Antidegradation 

requirements and methods for implementing those requirements are minimum conditions to be 

included in a State’s water quality standards.” EPA clarifies here that there was no pre-existing 

requirement for adoption of implementation methods as WQS. The 1994 WQS Handbook statement 

inaccurately portrayed the previously existing requirements; the Handbook (which is a guidance 

document) cannot establish requirements that do not exist in regulation. EPA intends to correct this 

inaccuracy subsequent to publishing this final rule.

A comment saying that EPA must require adoption of antidegradation implementation methods to 

ensure implementation cited to Title 33 of the United States Code (U.S.C.) section 1313(d)(4)(B); 

33 U.S.C. section 1313(c)(3) & (4); Water Quality Guidance for Great Lakes System, 40 CFR Part 132; and 

EPA Region IV’s September 24, 1987 letter to the state of Florida. EPA disagrees; none of these citations 

say that states and authorized tribes must adopt implementation methods. The comment said that 

EPA’s letter to the state of Florida was an Administrator’s Determination and provided evidence that 

clustering a state’s antidegradation requirements (including implementation methods) in one location in 

the state’s WQS is necessary to meet the requirements of the CWA. EPA disagrees. Not only was the 

letter to Florida not an Administrator’s Determination (see final preamble discussion on what 

constitutes an Administrator’s Determination), but the letter also did not say that antidegradation 

implementation methods must be adopted into regulation. For reasons explained elsewhere in this 

essay, the final rule does not require adoption of implementation methods.

Commenters stated that requiring legally binding implementation methods would improve the ability of 

authorized tribes to protect downstream waters, improve program implementation and help ensure 

consistency with the CWA. EPA agrees that legally binding implementation methods support protection 

of downstream waters, better program implementation, and consistency with the CWA. However, EPA’s 

view is that non-binding implementation methods can also support these positive outcomes and 

therefore, EPA did not find a compelling reason to require adoption of methods into rule. 

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Comments stated that without legally binding implementation methods, antidegradation can be 

inconsistently applied, inadequately enforced, or negated by the provisions of a state’s non-binding 

methods. EPA’s view is that regardless of whether states’ and authorized tribes’ methods are legally 

binding, it is possible that antidegradation can be inconsistently applied or inadequately enforced. 

EPA finalized today’s new regulatory requirements to improve consistency of implementation. EPA 

points out here that non-binding antidegradation implementation methods cannot negate legally 

binding antidegradation policies for purposes of the CWA.

1 Even if a state or authorized tribe has legally 

binding implementation methods approved by EPA as consistent with the CWA and the regulation at 

40 CFR Section 131.12, in some cases the state or authorized tribe may fail to consistently apply or 

adequately enforce their antidegradation policy, or may fail to apply it altogether. EPA’s recourse in this 

event would generally be through its oversight discretion of the relevant implementation program 

(e.g., National Pollutant Discharge Elimination System (NPDES)) and not through the WQS program.

Depending on the circumstances, it may also be possible for EPA to make an Administrator’s 

Determination that new or revised WQS are needed, at the Administrator’s discretion. 

EPA agrees with comments stating that the public has a right to know how states and authorized 

tribes intend to implement the CWA and have input on state and authorized tribal decision-making 

processes. EPA also agrees with the importance of public participation for the regulated community 

and other stakeholders. EPA also agrees that state and authorized tribal rulemakings can be a vehicle 

to achieve public participation requirements. Commenters stated that requiring adoption of 

implementation methods would enhance public participation and provide transparency and 

accountability in the development of implementation methods. Commenters also stated that this 

would lead to greater consistency nationwide. However, EPA disagrees with comments stating that 

binding methods are necessary to improve transparency, accountability, to enhance public 

involvement, and to increase confidence in state programs. The final rule requires that states and 

authorized tribes provide an opportunity for public involvement during the development and revision 

of their antidegradation implementation methods. This requirement applies whether or not those 

methods are legally binding.

EPA disagrees with comments stating that requiring legally binding implementation methods would 

ensure they are updated regularly as part of triennial reviews. Commenters provided no explanation for 

why this would be a logical outcome. EPA’s experience is that states and authorized tribes do not always 

regularly update all parts of their designated uses, criteria, or antidegradation policies through triennial 

reviews, despite the fact that all of those are required components of states’ and authorized tribes’ 

legally binding WQS. On the other hand, EPA received many comments that retaining antidegradation 

implementation methods in guidance would allow states and authorized tribes to refine and update 

their implementation methods more frequently than they otherwise would if they were required to go 

through a formal rulemaking for each revision to their implementation methods.

 

1 EPA makes clear in its final rule at section 131.5(a)(3) that where states and authorized tribes adopt legally 

binding antidegradation implementation methods, such methods are subject to EPA review and approval or 

disapproval.

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Commenters stated that undisclosed promises in non-binding antidegradation implementation methods 

made by states and authorized tribes to EPA are not consistent with sound public policy, the CWA, or 

the state Administrative Procedures Acts. EPA determined that the most reasonable way to address this 

concern is to require in the final rule that states’ and authorized tribes’ antidegradation implementation 

methods be publicly available and that states provide an opportunity for public involvement during the 

development and revision of any antidegradation implementation methods. EPA found that public 

involvement is important to increase transparency, accountability, and consistency in states’ and 

authorized tribes’ implementation. Thus, today’s rule provides for public involvement during 

development or revision of implementation methods. 

EPA disagrees with the comment that because implementation methods deal with high quality waters, 

they should be subject to EPA review. EPA recognizes the importance of high quality waters, but 

determined that the most balanced approach is to require public involvement, but not require states 

adopt methods into rule, for the reasons stated above. 

EPA agrees with a commenter stating that CWA section 501(a) authorizes the EPA Administrator to 

“prescribe such regulations as are necessary to carry out his functions under this chapter.” EPA has 

authority under the CWA to require antidegradation implementation methods in binding form, but the 

Agency chose not to impose this requirement at this time after full consideration. It is not necessary to

require states and authorized tribes to adopt implementation methods in order to carry out functions of 

the Act as discussed the final preamble and in other parts of this response.

EPA agrees with comments explaining that requiring state or authorized tribal adoption of 

implementation methods would not remove state and authorized tribal primacy to decide how to 

address implementation in the methods, and that it would help ensure that states meet consistent 

requirements in executing that primary role. EPA agrees that when states’ and authorized tribes’ 

methods are adopted into binding form, EPA has a secondary role in reviewing them to ensure they are 

at least minimally sufficient. EPA does not have the primary role of deciding how states and authorized 

tribes will implement their programs. EPA also agrees with comments that EPA could require adoption 

of implementation methods while still allowing flexibility for states and authorized tribes to tailor their 

methods to local needs. Though the final rule does not require adoption of implementation methods, it 

is still the case that states and authorized tribes adopting their methods have flexibility with respect to 

tailoring methods to local needs. EPA encourages states and authorized tribes to consider adopting 

implementation methods as legally binding, to incur advantages such as providing a greater degree of 

regulatory certainty to regulated entities.

EPA agrees with comments stating that because EPA outlined the minimum elements of implementation 

methods in the preamble to the proposal, states and authorized tribes have the information they need 

to know what elements their methods must address in order to obtain approval. EPA notes that the fact 

that a state or authorized tribe’s implementation methods addresses all of the elements does not 

guarantee approval; it must address those elements in a manner consistent with the requirements of 

the CWA and the WQS regulation.

Commenters stated that requiring adoption of antidegradation implementation methods would lead to

more consistent implementation nationally, and a more consistent, uniform approach to EPA evaluating 

those methods. Commenters did not provide an explanation for their assertion that it would lead to 

more consistent implementation. EPA agrees that if all states’ and authorized tribes’ methods were 

adopted as legally binding, EPA would have a more “uniform” approach to evaluating methods in the 

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sense that EPA would have legal authority to act directly on all of them. EPA also agrees with 

commenters that adoption of antidegradation implementation methods can have positive implications 

for NPDES permits, better public information and participation, and clearer information for the 

regulated community. However, EPA disagrees that it is necessary to require adoption of 

implementation methods in order to achieve this same consistency, uniformity and other positive 

results at this time. While implementation methods can and should vary state by state/tribe by tribe, in 

order to accommodate state/tribal specific waters and processes, with the proper public involvement 

and early EPA engagement, non-binding antidegradation implementation methods can be just as 

thorough and effective as binding implementation methods with state/tribal commitment to 

implementing the methods, as written.

Some commenters supported requiring adoption of implementation methods because in some states, 

laws prohibit the state’s environmental protections from being more protective than the minimum 

federal baseline. Comments stated that environmental managers in those states will be prevented from 

adopting their implementation methods if EPA does not require it. EPA observes that it is true that some 

states prohibit the adoption of WQS more protective than the federal minimum. While EPA encourages 

states and authorized tribes to consider adopting more protective WQS, the final rule does not require it 

because EPA does not view it as necessary for adequate antidegradation implementation. The final rule 

retains state and authorized tribal flexibility in deciding whether or not to adopt antidegradation 

implementation methods or whether to keep them as non-binding guidance documents. As stated 

above, EPA found that non-binding methods can be as effective as binding methods.

EPA disagrees with comments stating that the fact that half of states have adopted their antidegradation

implementation methods and put themselves in a position for EPA to conduct formal review under CWA 

section 303(c) demonstrates that requiring adoption of implementation methods is not as onerous as it 

might sound. In some states and authorized tribes, adoption may not be onerous, but the commenter 

did not provide an explanation for the generalization that adoption would not be onerous for other

states and authorized tribes. Furthermore, EPA also received other comments from many states that 

adopt their antidegradation implementation methods. Those commenters said that while these states 

chose to adopt their methods, they specifically commented that they did not agree it should be a federal 

requirement but continue to be a decision left to the states. EPA does not agree that such a requirement 

is necessary nor does it agree that EPA should require adoption of implementation methods because 

half of the states already adopt. In fact, other commenters with direct experience working in state 

programs indicated that the process of adoption is indeed onerous for their states. The breadth of 

comments demonstrate that adopting implementation methods may be onerous for some states and 

authorized tribes but not onerous for others. As stated above, EPA found that specific state examples 

describing the burden of adopting implementation methods were compelling. As described elsewhere in 

this essay, EPA found that requiring adoption of implementation methods was not necessary, and that it 

is possible to achieve the protection required by the federal regulation without adding a requirement 

that may cause some states and authorized tribes a burden that could impede their ability to focus 

resources on actually implementing the regulation. 

Commenters expressed specific concerns about a specific state’s implementation methods and concern 

that those methods may remain outside of EPA’s authority unless the state is required to adopt them. 

The commenters were concerned that the state’s methods undermine the state’s legally binding policy. 

EPA considered these concerns and determined that regulation is not necessary. EPA found that to 

address these concerns, it was reasonable to adopt the requirement for an opportunity public 

involvement in development and revision of methods and making the methods publicly available. EPA 

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encourages commenters and other citizens concerned about a specific state’s or authorized tribe’s 

implementation methods to bring up concerns directly with the state or authorized tribe, as this can 

facilitate revision of the methods to be consistent with the state’s or authorized tribe’s legally binding 

policy. If a state or authorized tribe fails to consistently apply or adequately enforce their 

antidegradation policy, for example, by following implementation methods that undermine the policy 

when preparing an NPDES permit, EPA’s recourse in this event would generally be through its oversight 

discretion of the relevant implementation program (e.g., NPDES). Depending on the circumstances, it 

may also be possible for EPA to make an Administrator’s Determination that new or revised WQS are 

needed, at the Administrator’s discretion. 

EPA received comments stating that EPA must not only require adoption of implementation methods

but that it must require that such methods identify all activities subject to antidegradation review. The 

comment stated that such activities must not be limited to activities requiring an NPDES permit, and 

must include nonpoint source (NPS) pollution, stormwater pollution, water withdrawals and water 

transfers that affect water quality, best management practices (BMPs), and activities a state or 

authorized tribe proposes to exempt from permitting. EPA disagrees. While it is true that 

antidegradation (as all other WQS) applies to water bodies and is not limited to specific types of 

activities, the CWA does not explicitly require that states and authorized tribes regulate NPS activities or 

that certain activities cannot occur before meeting the requirements of WQS. However, when states and 

authorized tribes assess whether their waters are meeting WQS every two years, they are required to 

list waters not meeting WQS as “impaired,” regardless of source of impairment. Comments stated that 

no activities may be excepted from antidegradation policy and review for compliance with 

antidegradation policy. EPA partially agrees and partially disagrees. Part of the comment is based on a 

misconception. EPA clarifies here that activities may not be excepted from a state’s or authorized tribe’s 

antidegradation policy, because the policy applies to water bodies and not to activities. EPA agrees that 

generally it is inappropriate to categorically exempt one or more types of activities from antidegradation 

review on the basis of the activity “complying with the antidegradation policy.” One exception would be 

that a state or authorized tribe may choose to categorically exempt NPS activities from antidegradation 

review (but not from the policy itself), as discussed previously. A state or authorized tribe may also 

choose to exempt from antidegradation Tier 2 review (but not from antidegradation Tier 1 protection)

activities that fall under a de minimis threshold, as discussed in the preamble to the final rule and 

elsewhere in the response to comments. 

EPA agrees with commenters that water bodies or water courses that are waters of the United States 

may not be categorically excepted from states’ and authorized tribes’ antidegradation policies, because 

waters of the United States are subject to WQS. (Likewise, waters may not be categorically exempted 

from having designated uses or criteria.) However, to the extent that a water body or water course is 

not a water of the U.S., the state or authorized tribe with jurisdiction over the water has the discretion 

as to whether to provide protections under its WQS. EPA does not have authority to require that states 

and authorized tribes apply WQS to waters that are not waters of the U.S.

EPA disagrees with a comment stating that EPA should require states and authorized tribes to adopt 

implementation methods, and then promulgate methods for them if they fail to do so within one year.

EPA chose not to require adoption of implementation methods for the reasons stated elsewhere in this 

essay. 

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EPA agrees with a comment that the language of the previously existing regulation at 40 CFR section 

131.12 gives EPA the ability to examine whether states’ and authorized tribes’ implementation methods 

are consistent with section 131.12 and that “antidegradation” is part of WQS subject to EPA review and 

approval and disapproval. EPA agrees that when states and authorized tribes adopt or revise legally 

binding antidegradation policies, EPA has the authority and duty to act on them under 303(c)(3). 

However, EPA disagrees with comments stating that the federal regulation at 40 CFR section 131.12 has 

always “required” that states and authorized tribes adopt implementation methods and that EPA 

“determine” whether states’ and authorized tribes’ methods are consistent with 131.12. Some 

comments cited to court opinions (CORALations v. EPA, 477 F. Supp. 2d 413, 416 (D. P.R. 2007); Ohio 

Valley Envtl. Coal. v. Horinko, 279 F. Supp. 2d 732, 738 (S.D. W.Va. 2003)) as saying that states must 

submit their antidegradation policy and implementation methods to EPA. EPA’s view is that the 

previously existing WQS regulation required only that state and authorized tribal implementation 

methods be “identified” (131.12). Because the previously existing regulation required that methods be 

“identified,” EPA did have the ability to examine states’ and authorized tribes’ non-binding 

implementation methods. EPA examined them for consistency with their binding policies. However, EPA 

did not and does not have the authority or mandatory duty under CWA section 303(c) to approve or 

disapprove implementation methods that are not adopted as legally binding.2 Commenters also cite to 

40 CFR section 130.7(b)(3) which defines “applicable water quality standards” for total maximum daily 

loads (TMDLs) to include “antidegradation requirements.” EPA agrees that this citation correctly points 

out that applicable WQS do include antidegradation requirements; however, the TMDL regulations do 

not speak to this issue of antidegradation implementation methods, so the regulations are not relevant 

to this discussion.

EPA agrees with comments that states should not be required to adopt into binding form provisions for 

antidegradation implementation that merely proscribe non-substantive procedures for making 

decisions. For reasons stated elsewhere in this essay, the final rule does not require adoption of 

implementation methods.

EPA disagrees with comments that because antidegradation can affect NPDES permits, implementation 

methods should be adopted. The requirements of NPDES permits are affected by guidance and other 

non-binding documents (e.g., NPDES Permit Writers’ Manual, Technical Support Document for Water 

Quality-based Toxics Control) as well as binding requirements. There is no requirement that anything 

affecting an NPDES permit must be adopted into binding regulation. EPA’s proposal did suggest that this 

may be a consideration when deciding whether or not EPA should require adoption of antidegradation 

implementation methods. However, EPA received comments that there are many other guidance 

documents that affect NPDES permits. Thus the EPA determined this consideration was not enough to 

determine that it is necessary to require that antidegradation implementation methods be adopted as 

legally binding.

 

2 EPA’s position is consistent with the cases cited by the commenters. In the Ohio Valley Envtl. Coal. case, West 

Virginia had adopted the implementation methods into regulation, thus EPA reviewed those methods as WQS. 

Ohio Valley Envtl. Coal. 279 F. Supp. 2d 732, 739 (S.D. W.Va. 2003). In addition, in CORALations v. EPA, the question 

for the court was whether, in the absence of Puerto Rico’s identification of any implementation methods, EPA had 

the mandatory duty to identify methods in regulatory form for Puerto Rico. EPA argued that the Agency was not 

required to identify methods in regulatory form. The court said that “this is true generally for identifying methods” 

but went on to find that since the implementation methods were nonexistent, EPA was required to publish 

proposed regulations pursuant to CWA section 303(c)(4)(B). CORALations v. EPA, 477 F. Supp. 2d 413, 418 (D. P. R. 

2007).

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Commenters stated that EPA should clarify that any implementation rule that affects the circumstances 

or conditions under which permits are granted must be adopted as a WQS and presented to U.S. EPA for 

approval. They pointed to court cases to support the statement that if a state or authorized tribal rule 

has the actual effect or practical impact of a standard, it is a standard and must be subject to EPA action 

(Florida Pub. Interest Research Group v. U.S. EPA, 386 F.3d 1070, 1088-9 (11th Cir. 2004); Northwest 

Environmental Advocates v. U.S. EPA, 855 F. Supp. 2d 1199, 1211 (D.Ore. 2012); Ohio Valley 

Environmental Coalition v. Horinko, 279 F. Supp. 2d 272, 763-65 (S.D. W. Va. 2003).) Commenters 

argued that binding, substantive provisions in states’ and authorized tribes’ antidegradation 

implementation rules have a practical effect on the meaning of WQS because they affect whether 

permits are granted and the water quality-based effluent limits (WQBELs) in those permits, the 

circumstances in which degradation may be allowed, substantive decisions in 401 certifications, and 

whether waters are listed under 303(d). Some commenters stated that when implementation methods 

are applied this way, they have a practical effect on the meaning of WQS and are WQS. Commenters 

stated that whether a state or authorized tribe calls their legally binding antidegradation 

implementation methods an “implementation rule” or something else, and no matter where it appears 

in its rules, it is subject to EPA action under CWA 303(c). EPA agrees with all of the above statements, 

and points out that the key is that states’ and authorized tribes’ antidegradation implementation 

methods constitute WQS subject to EPA action under CWA 303(c) when they are adopted as legally 

binding. When antidegradation implementation methods are not adopted as legally binding, the 

antidegradation standards that other implementation programs must use (e.g., for developing WQBELs 

or for deciding whether a water will be 303(d) listed) are the provisions of the legally binding, EPAapproved antidegradation policy. Commenters stated that EPA should caution states and authorized 

tribes to make sure that they submit every binding rule that has the effect of a WQS to EPA for review 

and approval whatever they want to call the rule. EPA encourages states and authorized tribes to submit 

their legally binding antidegradation implementation methods to EPA for review and action. However, 

even if a state or authorized tribe fails to submit them, EPA has authority to act on such methods as 

discussed in EPA’s 2012 FAQs titled “What is a New or Revised WQS under CWA section 303(c)(3)” found 

at http://water.epa.gov/scitech/swguidance/standards/cwa303faq.cfm. 

EPA disagrees with commenters stating that the list of minimum elements for implementation methods 

that EPA had outlined in the proposal preamble was evidence that major elements of antidegradation 

implementation methods have practical effects, and therefore are WQS that must be adopted as legally 

binding. As EPA has discussed in this essay, while such elements are indeed minimum elements of an 

antidegradation implementation method that is consistent with an antidegradation policy, at this time 

EPA has concluded that it is unnecessary for any or all of these elements be binding in order to be 

consistent with the antidegradation policy. A state or authorized tribe’s antidegradation policy are the 

ultimate WQS that have practical effect through implementation actions consistent with that policy.

Where states and authorized tribes adopt their implementation methods, then those serve as additional 

applicable WQS. However, where they remain as guidance, implementation must continue to be 

consistent with the policy, however the state or authorized tribe chooses to implement the policy.

Some commenters expressed concern regarding how guidance is used or cited in NPDES permits when 

there are no underlying rules. Such comments were not directly about antidegradation guidance but 

commenters were concern that the same issues could be raised if antidegradation implementation 

methods were not required to be adopted. Based on the comments, as written, this comment relates to 

how NPDES permits are written and defended, and is outside the scope of this rulemaking.

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EPA disagrees with comments that state and authorized tribal antidegradation implementation methods 

often amend, revise, or abandon the antidegradation standards adopted by states and authorized tribes. 

Commenters provided no evidence that states’ and authorized tribes methods “often” are inconsistent 

with their legally-binding policies. EPA’s position is that non-binding methods cannot amend, revise, or 

abandon the legally binding antidegradation policy. Just because a state or authorized tribe may choose 

to act contrary to its own legally binding, CWA-effective WQS does not mean that the WQS have 

changed; rather, it indicates failures of implementation. EPA has discretionary oversight authority for 

programs that implement WQS. For example, EPA has the discretionary authority to object to an NPDES 

permit that fails to appropriately implement applicable WQS. EPA also has discretionary authority to 

make an Administrator’s Determination that new or revised WQS are necessary. Decisions to exercise 

oversight authority over implementation or to make an Administrator’s Determination are made on a 

case-by-case basis.

Commenters stated that due to the current deficient state and authorized tribal antidegradation 

implementation methodologies, to date the effluent limitations based upon TMDLs and wasteload 

allocations (WLAs) established under CWA section 303(d) have not complied with the antidegradation 

policy established under the CWA as mandated by CWA section 303(d)(4)(B). The commenter did not 

provide any evidence to support a claim that this failure is a result of the lack of binding antidegradation 

implementation methods. As discussed earlier, such failure could occur whether or not implementation 

methods are legally binding.

EPA disagrees with comments stating that if states have compiled methods in guidance documents the 

result is a “hodgepodge” that is not appropriate for this key aspect of state or authorized tribal WQS. 

EPA’s view is that provided a state or authorized tribe has a legally binding antidegradation policy 

consistent with the CWA and 131.12, it is possible to have effective implementation methods in 

guidance just as it is possible to have effective implementation methods for any subject area in guidance

(e.g., variance policies, low flow policies, designated use policies, mixing zone policies, etc.). The key is 

that such implementation methods are consistent with the state’s or authorized tribe’s own applicable, 

CWA-effective regulations. Today’s rule makes clear that EPA has the authority to review and approve or 

disapprove any implementation method, including antidegradation implementation methods that states 

and authorized tribes adopt as legally binding. As explained elsewhere in this essay, the statement of 

this authority in rule does not create a new requirement, but clarifies the longstanding requirement to 

prevent confusion.

Commenters provided a state-specific example involving a court case related to a state’s 

implementation methods and EPA action, and cited concerns about that state’s implementation 

methods. State-specific concerns are outside the scope of this national rule since EPA is not 

promulgating standards for individual states. However, commenters used the specific state example as 

an illustration of their point that EPA should promulgate a requirement that all states and authorized 

tribes adopt their implementation methods, because there is no other way for EPA to achieve its stated 

goal that: “states and tribes must develop and make available to the public antidegradation 

implementation methods to improve program implementation, ensure consistency with the CWA, and 

provide transparency as to applicable state and tribal antidegradation review requirements.” Fed. Reg. 

at 54529. They asked what EPA will do when a state demonstrates that its non-binding implementation 

methods are not sufficient to ensure implementation and are not consistent with the CWA. Other 

commenters cited to ManaSota-88, Inc. v. Tidwell, 896 F.2d 1318, 1320 (11th Cir. 1990) as evidence that 

the state antidegradation policy and implementation criteria must be “consistent with and at least as 

stringent as the federal anti-degradation rule. 40 C.F.R. 131.12.” Commenters used this conclusion as 

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evidence that EPA must require adoption of antidegradation implementation methods so that EPA has 

the ability to take action and ensure that states’ and authorized tribes’ methods are “consistent with 

and at least as stringent as” 131.12. EPA agrees that states’ and authorized tribes’ antidegradation 

implementation methods must be “consistent with and at least as stringent as” 131.12, but does not 

agree that it follows that antidegradation implementation methods must be adopted. While EPA would 

not have the authority to disapprove non-binding implementation methods, EPA has other means of 

recourse. Depending on the specific circumstances, EPA may be able to disapprove a state’s or 

authorized tribe’s new or revised legally binding antidegradation policy if its accompanying 

implementation methods are inconsistent with its antidegradation policy, the Act, and/or section

131.12. The EPA Administrator may be able to make an Administrator’s Determination that a state or 

authorized tribe needs new or revised WQS. (Administrator’s Determinations are at the Administrator’s 

discretion.) Finally, EPA has the discretionary authority to object to state or authorized tribal permits for 

activities affecting water quality if such permits are written to implement the inconsistent 

implementation methods and are thus do not derive from and comply with the applicable WQS, in this 

case the state’s or authorized tribe’s antidegradation policy. 

The previously existing antidegradation regulation required that “the state shall develop and adopt” an 

antidegradation policy, and that the state shall “identify” implementation methods. EPA agrees with a 

comment that its proposal to change the regulatory text from requiring that states and authorized tribes 

“identify” implementation methods to requiring that they “develop” implementation methods did not 

add anything to the previously existing regulation. (If a state or authorized tribe can “identify” its 

implementation methods, logically, it must have “developed” such methods.) The intention of the 

proposal was to make explicit the requirement to develop an antidegradation implementation method 

as some did not interpret “identify” in that manner, as shown in some of the comments received on this 

rule. The final rule provides clarity by making the requirements parallel by using the word “develop”: 

“The State shall develop and adopt a statewide antidegradation policy” and “The State shall develop 

methods for implementing the antidegradation policy...” and “The State shall provide an opportunity for 

public involvement during the development and any subsequent revisions of the implementation 

methods, and shall make the methods available to the public.” With this structure, it is clear that both 

policy and methods must be developed, while only the policy must be adopted.

EPA received a comment stating that EPA frequently approves “sometimes questionable state WQS, 

particularly antidegradation requirements, on the promise of a state to interpret or apply the 

requirement in a particular way.” The comment also cited concern about a specific state’s 

implementation, and stated that citizen advocates reported problems to EPA because EPA did not 

discover the problems through monitoring state compliance. The commenter stated that this places 

unfair burdens on citizens to do EPA’s job. The commenter further stated that state promises regarding 

implementation must be incorporated into state rules and subject to EPA action in order to ensure that 

states follow through on them, and to create disincentives for states to apply antidegradation 

requirements in a manner inconsistent with their representations to EPA and the public. EPA agrees that

adopted methods are more likely to facilitate consistent implementation than methods in guidance. 

However, EPA disagrees that adopted methods “ensure” that states follow through. Adoption of 

implementation methods in rule does not ensure that anything specific will be implemented. It simply 

provides additional avenues for the public to challenge situations in which there is a failure to 

appropriately implement those methods. As discussed in this essay, EPA’s possibilities for recourse 

where states fail to implement antidegradation requirements consistent with their CWA effective 

antidegradation policy remain the same regardless of whether or not the antidegradation 

implementation methods are legally binding. In addition EPA’s requirement that states and authorized 

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tribes provide an opportunity for public involvement on the development and subsequent revision of an 

antidegradation implementation method provides the expectation that the public is fully involved and 

informed of the antidegradation implementation methods whether they are binding or not.

C. Comments That Support Requiring Public Availability of Implementation 

Methods

EPA received comments supporting the proposed requirement that states and authorized tribes make 

their antidegradation implementation methods available to the public. EPA agrees with commenters 

that some states have implementation methods in guidance that are unknown to the public and 

regulated community, and that this lack of transparency is problematic. EPA also agrees with the goal of 

ensuring that antidegradation policies are consistently implemented throughout the country. (States 

and authorized tribes need not implement their policies identically to one another; but implementation 

should be consistent at least at a basic level.) EPA agrees with comments stating that the public has a 

right to know how states and authorized tribes intend to implement the CWA and have input on state 

and authorized tribal decision-making processes. EPA also agrees with the importance of public 

participation for the regulated community and other stakeholders. EPA also agrees that state and 

authorized tribal rulemakings can be a vehicle to achieve public participation requirements. 

Commenters stated that requiring adoption of implementation methods would enhance public 

participation and provide transparency and accountability in the development of implementation 

methods. Commenters also stated that this would lead to greater consistency nationwide.

EPA also agrees with comments suggesting that the proposal did not go far enough because it did not 

provide for public participation in the development or revision of antidegradation methods, as it only 

requires a state to “make available” the antidegradation implementation methods after development. 

EPA incorporated the commenter’s suggestion of enhancing the public’s ability to provide input, rather 

than simply allowing the public to view antidegradation implementation methods after they are 

finalized or changed.

Thus, for the reasons stated throughout this essay, the final rule requires that antidegradation 

implementation methods be available to the public and it requires that states and authorized tribes 

provide an opportunity for public input in development of and subsequent revision of antidegradation

implementation methods.

D. Comments That Oppose Requiring Public Availability of Implementation 

Methods

EPA disagrees with commenters who opposed the proposed requirement that states and authorized 

tribes make their antidegradation implementation methods available to the public. EPA explains 

elsewhere in this essay the reasons why EPA’s final rule requires implementation methods be made 

available to the public. The final rule requires that antidegradation implementation methods be 

available to the public and it requires that states and authorized tribes provide an opportunity for public 

input in development of and subsequent revision of antidegradation implementation methods.

Some commenters expressed concern that there is no differentiation between “procedures” (which 

would be public as a result of EPA’s rule) and internal guidance and standard operating procedures 

(SOPs). EPA recognizes that states and authorized tribes may rely on internal guidance or SOPs for some 

details about implementation. As long as the state’s or tribe’s antidegradation implementation methods 

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document(s) address, at a minimum, how all the elements required by the regulation at 40 CFR section

131.12 will be implemented, the state or authorized tribe may choose to address other aspects of 

implementation or more minute details in internal documents that are not publically available. Those 

internal documents should support and be consistent with the antidegradation implementation 

methods, rather than contradict them. The goal of the requirement is to ensure that the public can 

obtain a realistic understanding of how the antidegradation policy will be implemented and has an 

opportunity to provide input. 

Some commenters stated that there is already transparency in the regulations that allows public 

participation through states’ and authorized tribes’ own processes, i.e., the NPDES permits process. EPA 

agrees that other processes, such as the NPDES permit public notice comment period, provide an 

opportunity for public input. However, the public must have access to information on how states and 

authorized tribes will implement antidegradation ahead of the method actually being used. This allows 

them to be prepared to examine how a state or authorized tribe will implement antidegradation 

requirements related to a specific activity (e.g., one proposed for an NPDES permit) in light of the state 

or authorized tribe’s own antidegradation policy and to provide public input, accordingly so as to 

influence those decisions. The final rule requires states and authorized tribes to provide an opportunity 

for public involvement in the development and revision of implementation methods, so that they may 

have meaningful influence on how the state protects its public water resources from degradation. That 

is, the public could help shape the implementation methods that will be used for many activities in the 

future, rather than simply having to comment when they object to the treatment of each individual 

proposed activity.

EPA disagrees with comments that opposed the proposed requirement that antidegradation 

implementation methods be available to the public on the grounds that the requirement would 

inappropriately expand EPA’s review authority because implementation methods aren’t WQS and aren’t 

subject to review. The final rule does not make all states’ and authorized tribes’ implementation 

methods subject to EPA review under 303(c). Implementation methods that are not adopted as legally 

binding are not subject to EPA review under 303(c). The requirement to make the antidegradation 

implementation methods available to the public and to provide an opportunity for public input is 

independent of whether EPA required all states and authorized tribes to adopt antidegradation 

implementation methods as legally binding.

EPA disagrees with comments that opposed the proposed requirement that antidegradation 

implementation methods be available to the public on the grounds that it is not necessary since 40 CFR 

section 131.20(b) already requires states to hold public hearings for reviewing WQS, and 40 CFR section

122 and 40 CFR Part 25 have other requirements for public participation. These cited requirements 

apply to new or revised WQS but do not impose any obligation on antidegradation implementation 

methods that are not adopted as legally binding by a state or authorized tribe. Thus, without today’s 

requirements some states’ and authorized tribes’ implementation methods may not be available to the 

public and the public may have no avenue to provide input on the antidegradation implementation 

methods before such methods are finalized and used. 

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E. Comments Questioning How the Rulemaking Affects State and Authorized 

Tribe Antidegradation Policies and Implementation Methods Already 

Approved by EPA

Commenters asked EPA to clarify whether states can presume that the approvability of their currently 

approved antidegradation policies will not be affected by this rulemaking as the rulemaking does not 

seem to establish any new requirements or limitations on the scope of implementation. The final rule 

contains revised requirements at 40 CFR Part 131.12. States and authorized tribes should not presume 

that their currently approved antidegradation policies (and implementation methods, where applicable) 

will be unaffected by the final rule. EPA recommends states and authorized tribes evaluate their 

program for consistency with the final regulation at 40 CFR Part 131.12. The rulemaking process is 

established recognizing that the Federal regulations may need to change in order to better meet the 

objectives of the CWA as new environmental challenges arise and new science is developed. EPA is 

ready to assist any state or authorized tribe in evaluating their currently applicable antidegradation 

requirements to determine whether and what revisions are necessary to comply with the new 

requirements. EPA understands that any potential revisions may take time. Thus, the preamble to the 

final rule clearly explains “EPA’s expectation is that, where a new or revised requirement necessitates a 

change to state or authorized tribal WQS, such revisions will occur within the next triennial review that 

the state or authorized tribe initiates after publication of the rule.” 

A commenter stated that the proposal appears to presume that states have adopted an antidegradation 

policy in state regulation. EPA agrees with this statement. States and authorized tribes were already

required, prior to this rulemaking, to have adopted an antidegradation policy as a legally binding 

document. The commenter stated that a specific state has adopted an antidegradation policy which has 

been approved by EPA, though the policy is not incorporated into state regulation, and that since it was 

approved by EPA, it meets the federal requirement for state adoption of an antidegradation policy. EPA 

will not comment here on state-specific scenarios, but recommends that states and authorized tribes 

work with their EPA Regional offices to determine whether any changes are needed. EPA does point out, 

however, that a document can be legally binding under state or tribal law but exist outside of state 

regulations.

F. Comments Asking Whether the New Rules Apply to Previously Submitted 

Water Quality Standards

A comment expressed concern that EPA action on a specific state’s WQS submission will be delayed by 

EPA’s rulemaking. The commenter stated that EPA should judge a submission by rules in effect at time 

of submission, not proposed/future regulations. EPA has addressed this issue in section E of the 

preamble to the final rule.

G. Comments That EPA Must Stop Relying on Guidance and Policy as If It Were 

Rule

EPA received comment stating that EPA’s use of interim guidance, unadopted rules, draft policies and 

“reinterpretations” of existing rules must cease. Draft and interim documents should not be enforced as 

though they were adopted rules. EPA agrees that guidance, draft rules and policies are not the same as 

regulations and EPA does not operate as such. EPA’s authority to approve or disapprove states’ and 

authorized tribes’ WQS under CWA 303(c) is based solely on whether the new or revised WQS are 

consistent with the CWA and the WQS regulation. Therefore, EPA chose to make today’s targeted 

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revisions to place important requirements in the regulations (instead of in guidance documents which 

are unenforceable). The regulatory requirements will increase transparency and promote consistency.

H. Comments Requesting Clarification on Certain Issues

Commenters asked for clarification on EPA’s intent. A commenter stated that EPA’s proposed language: 

“(b) The State shall develop and make available...” could be read to require states to include or 

reference their antidegradation implementation methods in their state WQS, and requested that EPA

clarify what is being required. The proposed language did not require that states include methods in, or 

rule-reference methods in their WQS. It required that methods be developed and publicly available.

A commenter asked if states will be required to subject their implementation methods to the same 

public review and approval process as state WQS. While not required to be adopted by the final rule, if a 

state or authorized tribe adopts an antidegradation implementation method as legally binding, and EPA 

determines that the method is a new or revised WQS (for more information, please see 

http://water.epa.gov/scitech/swguidance/standards/cwa303faq.cfm), then the method will be subject 

to EPA review and approval or disapproval under CWA section 303(c). It is also subject to the same 

public participation requirements as any other new or revised WQS. If a state or authorized tribe does 

not adopt their methods as legally binding, the final rule requires that the state or authorized tribe 

provide an opportunity for public involvement which gives states and authorized tribes the discretion to 

choose how to involve the public. EPA chose not to require states to follow the requirements at 40 CFR 

section 131.20(b) and Part 25 for their antidegradation implementation methods; instead, the final rule 

requirement for “public involvement” will achieve the goal of public transparency and engagement 

while retaining flexibility for states and authorized tribes in terms of how to engage the public. Please 

see the preamble to the final rule for additional discussion of these requirements. 

A commenter stated that two statements in the proposal were contradictory: that states may choose to 

adopt implementation methods (131.5(a)(3)) and that states “shall develop” implementation methods 

(131.12(b)). EPA disagrees. These statements are not contradictory. States and authorized tribes were 

already required to “identify” implementation methods under section 131.12(a) prior to today’s final 

rule. For an antidegradation implementation method to be “identified,” it would first need to be 

“developed.” The requirement to “develop” antidegradation implementation methods was thus already 

a requirement. While all states and authorized tribes must develop antidegradation implementation 

methods, the proposal and the final rule clarify that adopting such methods in a legally binding manner 

is at the state’s or authorized tribe’s discretion. This does not contradict the pre-existing requirement to 

identify (which would include developing) implementation methods.

A commenter requested clarification on EPA’s intentions in the preamble discussion at section E on page 

54525 of the Federal Register Vol. 78, No. 171 describing the change to the regulation as “specifying that 

states and tribes must develop and make available to the public implementation methods for their 

antidegradation policies.” The commenter asked whether EPA intends to require implementation 

methods. EPA already required implementation methods (per the previous version of 131.12 to 

“identify” methods) and still requires implementation methods. The commenter asked whether EPA 

intends to require adoption of implementation methods into standards or not. EPA requested comment 

on that very point in order to decide whether to require adoption of methods. The final rule does not 

require it.

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I. Comments That EPA Should Revise Language to Clarify That Antidegradation 

Implementation Is Only through Permitting

EPA disagrees with a request that EPA add regulatory text to clarify that antidegradation 

implementation in permitting alone is an approvable approach, in order to prevent future litigation. As a 

component of WQS, antidegradation is broadly applicable to water bodies, not only to “permitted” 

activities. Many different types of activities can affect water quality and trigger antidegradation review, 

and not all of these are regulated by state or authorized tribal “permits.” For example, a federally-issued 

Federal Energy Regulatory Commission license could allow an activity affecting water quality. In that 

case, the relevant state or authorized tribe should ensure that its antidegradation policy is implemented 

in its 401 certification of the activity. Since antidegradation applies to water bodies, some states and 

authorized tribes may use their discretion to implement antidegradation review for NPS activities over 

which the federal government does not have authority. On the other hand, states and authorized tribes 

may choose not to regulate NPS pollution, and EPA may not force them to implement antidegradation 

review for NPS activities. However, it is important to note that determining whether to list a water 

under CWA 303(d) as not meeting WQS, is irrelevant of the pollutant source, even if the cause of 

impairment is NPS-related. Please see response essay 7.g.iii, sections D, K, and M for additional 

discussion.

J. Comments regarding EPA’s Implementation of Antidegradation

A commenter noted that EPA does not itself appear to have an antidegradation policy because none of 

the NPDES general permits have addressed antidegradation. The application of antidegradation policy to 

general permits is outside the scope of this rulemaking. EPA’s federal antidegradation policy is at 40 CFR 

section 131.12.

K. Comments regarding the Minimum Elements

For a response to comments on concerns that states and authorized tribes should not be required to 

adopt new policy or regulations as a result of today’s rule, please see response essay 7.g.ii, section B.

L. Comments Concerned with the Analysis of Alternatives Requirement

For a response to concerns that the analysis of alternatives requirements are onerous, essentially forces 

the states to perform a use attainability analysis (UAA), and is contrary to federalism under the CWA, 

please see response essay 7.e.ii, sections C, E, F, G, K, and O.

M. Comments regarding the Addition of “Based on Sound Scientific Rationale” 

For a response to comments regarding the addition of “based on sound scientific rationale” in section

131.5(a)(2), please see response essay 10.a.

N. Comments That EPA Is Writing Implementation Methods for States

EPA received some comments stating that “EPA is proposing first to write implementation methods for 

the states and then to review the states’ adoption of them to make sure the states get them right.” EPA 

disagrees. EPA’s regulations are not federal implementation methods. EPA’s final regulations require 

states and authorized tribes to adopt an antidegradation policy and to develop an antidegradation 

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implementation method, both of which must be consistent with the provisions in section 131.12(a).

Section 131.12(a) provides requirements for protecting water quality but leaves discretion to states and 

authorized tribes as to how such requirements will be met as long as it is consistent with section

131.12(a). EPA’s regulations, prior to this rule, was structured in the same way. EPA’s final rule only 

provides clarifications to ensure that state and authorized tribal antidegradation policies continue to be 

consistent with the CWA and to enhance opportunities for public involvement in the development and 

revision of antidegradation implementation methods.

O. Comments regarding Resubmission of Antidegradation Policies 

For a response to comments that states need not resubmit their antidegradation policy when submitting 

a new or revised use or water quality criterion, please see response essay 7.g.iii, section L.

P. Comments regarding Protection of Existing Uses and Limiting the 

Approaches to Identifying High Quality Waters

For a response to comments regarding requiring that antidegradation implementation methods include 

the protection of existing uses, please see response essay 7.g.iii, section I.

For a response to comments regarding limiting the identification of high quality waters to the 

parameter-by-parameter approach, please see response essay 7.d.ii.

Q. Comments regarding What Elements Must Be in a State Policy to Be 

Consistent with 131.12(a)

EPA received a comment that its revision to section 131.5 “does not provide any clarity on what 

elements a State’s antidegradation policy must include to be considered consistent with section

131.12(a).” 40 CFR 131.5 is purely an articulation of what EPA has the authority to review, which is why 

there is no additional detail in this section. However, EPA disagrees with the commenter that 131.12(a) 

is vague. EPA has written section 131.12(a) to provide the minimum requirements for antidegradation 

protection consistent with the CWA and these minimum requirements must be included in all 

antidegradation state policies. States and authorized tribes continue to have discretion on how to 

implement antidegradation to ensure the policy is met. Please see further discussion in the preamble to 

the final rule. In addition, by not requiring antidegradation implementation methods to be adopted, 

states and authorized tribes continue to have the flexibility to refine their implementation, as needed, 

as long as they provide an opportunity for public input.

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Essay 7.f.ii – Antidegradation Implementation Methods: General 

Comments on Implementation of Implementation Methods

A. Comments That Antidegradation Implementation Methods Are Key to 

Antidegradation Policy Success

The U.S. Environmental Protection Agency (EPA) agrees with comments pointing out that states’ and 

tribes’ implementation methods for antidegradation are key to the policy’s success. EPA’s view is that 

implementation methods are not only a longstanding requirement of the regulations, but are an 

important component that supports the implementation of antidegradation policies.

B. Comments That Antidegradation Implementation Methods Are Not Subject 

to EPA Review

To the extent that some comments imply that state and tribal implementation methods are not subject 

to EPA review under any circumstances, EPA disagrees with those comments. If a state or tribe does not 

adopt its methods into binding form, it is true that EPA does not have authority to take an action under 

Clean Water Act (CWA) 303(c) to approve or disapprove those methods. However, EPA does have 

authority to take 303(c) action on any state’s or tribe’s legally binding implementation methods, as 

explained in the preamble to the final rule. Please see response essay 7.f.i, section A for additional 

discussion.

C. Comments regarding Basing 303(d) Listing of Waters on Antidegradation 

Requirements

For a response to comments that EPA should specify that antidegradation is only implemented through 

permitting and that antidegradation should not be a basis for CWA 303(d) listing of waters, please see 

response essay 7.e.ii, section N, response essay 7.f.i, section I, and response essay 7.g.iii, sections C, D, 

and K.

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Essay 7.g – Antidegradation: Minimum Elements of an Antidegradation 

Implementation Method

No comments are assigned to this issue category, and thus no response is necessary.

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Essay 7.g.i – Antidegradation Minimum Elements: Agreeing with 

Identifying Minimum Elements in Preamble

A. Comments Supporting the Identification of Minimum Elements of 

Implementation Methods

Some comments support the identification of minimum elements of state and authorized tribal 

antidegradation implementation methods and some comments agree with the U.S. Environmental 

Protection Agency’s (EPA’s) statements in the proposal preamble that the minimum elements should be 

based on the existing requirements of section 131.12. EPA chose to not include a list of minimum 

elements in the final rule language. Minimum elements of antidegradation implementation methods are 

addressed in the preamble to the proposed rule.

Some commenters urged EPA to avoid further steps as they would be unnecessary and inconsistent with 

the federal/state division of responsibility required by Clean Water Act (CWA) 303. EPA agrees. 

Minimum elements of antidegradation implementation methods should be based on the regulatory 

requirements at section 131.12. The final rule continues to provide states and authorized tribes with 

discretion to decide how to address the elements of implementation methods; however, the elements

must be consistent with section 131.12 and not undermine the state’s or authorized tribe’s

antidegradation policy. Furthermore, states and authorized tribes have discretion to decide whether 

they address additional elements of antidegradation implementation beyond the minimum elements

expressed in section 131.12. 

B. Comments Asking EPA to Include a List of Required Minimum Elements of 

Implementation Methods into the Regulatory Text at Title 40 of the Code of 

Federal Regulations Section 131.12 

EPA disagrees with comments arguing that EPA should incorporate the list of minimum elements of 

implementation methods into the regulatory text of Title 40 of the Code of Federal Regulations (CFR) 

section 131.12.

EPA explained in the preamble to the proposed rule that the purpose of including the list of minimum 

elements in the preamble was to facilitate states’ and authorized tribes’ development of 

implementation methods that are consistent with the water quality standards (WQS) regulation. The 

preamble explained that the list was based on requirements currently found in the federal 

antidegradation regulation, as well as proposed requirements. It also explained that how states and 

authorized tribes address each of these areas in their methods is within their discretion, as long as it 

does not undermine their antidegradation policy or is otherwise inconsistent with the Act or EPA’s 

regulations. The elements derive from the elements of the regulation, which states and authorized 

tribes are already required to address in their antidegradation policies. Including such elements in 

regulation would be redundant of the regulation. EPA will consider providing a final list of minimum 

elements to facilitate antidegradation implementation in future antidegradation guidance documents

based on the final rule requirements. 

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C. Comments Requesting EPA to Revise Section 131.6 to Specify 

Implementation Methods Must Be Included in Submissions of Water Quality 

Standards to EPA

EPA disagrees with a comment requesting that EPA revise 40 CFR section 131.6 (Minimum requirements 

for submission) to specify that the implementation methods must be included in states’ and authorized 

tribes’ submissions of WQS to EPA.

EPA considered revising the rule to require that all states and authorized tribes adopt the entirety of 

their antidegradation implementation methods in rule to improve accountability and transparency, as 

some commenters suggested. EPA did not make this change because it would limit states’ and 

authorized tribes’ ability to easily revise their implementation methods in order to adapt and improve 

antidegradation protection in a timely manner. Some states and authorized tribes have difficulty 

adopting their methods because of resource constraints, state or tribal laws, or complex rulemaking 

processes. Instead of requiring adoption of implementation methods, today’s rule achieves more 

accountability by establishing specific requirements for states’ and authorized tribes’ antidegradation 

policies regarding two key aspects of Tier 2 implementation. Section 131.5(a)(3) makes explicit EPA’s 

authority to review states’ and authorized tribes’ antidegradation policies and any adopted 

antidegradation implementation methods and to determine whether those policies and methods are 

consistent with section 131.12. EPA recommends states and authorized tribes adopt binding 

implementation methods to provide more transparency and consistency for the public and other 

stakeholders and to increase accountability. If a state or authorized tribe does not choose to adopt the 

entirety of its implementation methods, EPA recommends adopting, at a minimum, any antidegradation 

program elements that substantively express the desired instream level of protection and how that level 

of protection will be expressed or established for such waters in the future.

In any case where a state or authorized tribe has implementation methods that are not legally binding, 

the final rule requires that those methods be publically available and consistent with section 131.12(a). 

EPA does not have authority to review and approve or disapprove as a WQS pursuant to CWA section 

303(c) any state antidegradation implementation methods that are not adopted as legally binding 

provisions. However, having antidegradation implementation methods publicly available, consistent 

with section 131.12 and the state’s antidegradation policy will provide more transparency and 

consistency for the public and other stakeholders to be involved and help provide accountability. 

Section 131.5(a)(3) now makes clear that under section 303(c) of the CWA, EPA will review and approve 

or disapprove state-adopted WQS, and the review includes a determination whether the state has 

adopted an antidegradation policy that is consistent with section 131.12 and whether any adopted 

antidegradation implementation methods are consistent with section 131.12.

D. Comments Suggesting Changes to the List of Minimum Elements

Some commenters provided several additional elements that EPA should include as minimum elements:

• A process for ensuring existing uses are protected under Tier 1 protections.

• A method for reviewing all reasonable alternatives to a new or increased discharge as part of a 

Tier 2 review and a requirement that discharge limits be set based on the least polluting, 

reasonable alternative.

• A description of the factors and process for determining if a new or increased discharge will 

accommodate “important” social or economic development.

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• A description of the public notice and comment requirements.

• An explanation of both the process for designating and for protecting Tier 3 waters (also known 

as Outstanding National Resource Waters (ONRWs), Outstanding Resource Waters, or other 

state-specific names).

While EPA agrees that these elements suggested by commenters would be useful elements to include in 

antidegradation implementation methods, EPA’s position is that the minimum elements of 

antidegradation implementation methods are those that are consistent with 40 CFR section 131.12. EPA 

encourages states and authorized tribes to consider including these additional elements suggested by 

the commenter and other elements that the state or authorized tribe deems appropriate. While the 

elements identified by the commenter relate closely to those in EPA’s list, they provide an additional 

level of detail than what is provided for in the specific regulatory language itself and could be considered 

to go beyond the requirements of that regulatory provisions. EPA will consider providing a final list of 

minimum elements to facilitate antidegradation implementation in future antidegradation guidance 

documents based on the final rule requirements.

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Essay 7.g.ii – Antidegradation Minimum Elements: Disagree with 

Identifying Minimum Elements in Preamble

A. Comments That EPA Does Not Have the Clean Water Act Authority to 

Establish Minimum Elements for Antidegradation Implementation Methods

The U.S. Environmental Protection Agency (EPA) received comments that EPA does not have the Clean 

Water Act (CWA) authority to establish “minimum requirements” for antidegradation implementation 

methods and that EPA is improperly establishing “regulatory requirements” through the minimum 

elements listed in the preamble. Some commenters also stated that under the CWA, states with primacy

are given the authority to implement their water quality standards (WQS), as long as they are not 

inconsistent with the Act and that such requirements infringe on this authority.

EPA disagrees. EPA did not use the preamble to impose regulatory minimum requirements on 

antidegradation implementation methods. The list of minimum elements that EPA included in the 

preamble to the proposal was derived from the elements already required by Title 40 of the Code of 

Federal Regulations (CFR) section 131.12, plus elements proposed to be included at 131.12. The list 

provided in preamble was solely to provide guidance for states and authorized tribes to use when 

developing and revising their own antidegradation implementation methods. EPA’s regulations at 

section 131.12, even before this final rule, were clear that both a state’s/authorized tribe’s 

antidegradation policy and implementation methods must be consistent with the requirements at 

section 131.12(a). The elements themselves would not constrain how states and authorized tribes 

implement the policy. States and authorized tribes continue to have authority to implement their own 

WQS consistent with the CWA.

Some commenters asked why minimum elements to “facilitate” State’s development of methods are

necessary “after States’ antidegradation policies have been in place for 30 years.” These same 

commenters thought that EPA’s inclusion of minimum elements is an “illegitimate way for the agency to 

attempt to control how States develop their antidegradation procedures.” For the same reasons 

discussed elsewhere in this essay, EPA disagrees. In regards to why “facilitation” is needed, while states 

and authorized tribes have had antidegradation policies for 30 years, questions have been raised 

through litigation regarding whether some state and authorized tribal antidegradation implementation 

methods are in fact consistent with the regulatory requirements and the CWA. As discussed in the 

preamble to both the proposed rule and the final rule, protection of high quality waters is critical to 

supporting economic and community growth and sustainability because they contribute to our public 

health, drinking water supplies, welfare of families and communities, tourism, and support unique and 

significant ecologies and species habitat. EPA received feedback from stakeholders that existing CWA 

antidegradation regulatory provisions and related guidance have not been fully successful in ensuring 

consistent and effective implementation of Tier 2 high quality water protection. Therefore, EPA’s final 

rule with its targeted revisions are intended to enhance this protection, promote consistency and 

increase transparency. The minimum elements are an articulation of these various pieces that the 

regulation requires must be addressed by implementation methods and includes the new requirements 

added in today’s final rule. 

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Some commenters disagreed with EPA establishing requirements for state antidegradation 

implementation methods in proposed section 131.12 and to review state antidegradation policies for 

consistency with those minimum requirements in proposed section 131.5(a)(3). They stated that the 

previously existing regulation at 40 CFR section 131.12 and at 40 CFR section 131.6 already “apply (or 

exceed) [the] maximum extent of EPA's authority over state antidegradation policies under the CWA” 

and that because the CWA does not specify elements of implementation procedures, those elements 

are most properly determined by the states. EPA disagrees. Under the CWA, EPA has the authority to 

promulgate regulations necessary to administer and implement the purposes of the Act, which includes 

antidegradation. See CWA section 501(a). EPA acknowledges that the CWA does not specify elements of 

implementation procedures. However, EPA’s regulations establish specific requirements for all states 

and authorized tribes to follow in order to meet the purposes of the Act to “maintain the chemical, 

physical and biological integrity of the Nation’s waters.” The preamble to the final rule explains why EPA 

made targeted revisions to the antidegradation requirements and how these revisions are necessary to 

meet objectives of the CWA. The minimum elements included in the proposed rule preamble articulate 

the fundamental requirements of an antidegradation policy as specified in section 131.12(a). And, as 

specified in the regulatory language previous to today’s final rule and is now included as part of section 

131.12(b) in this final rule “The State shall develop methods for implementing the antidegradation policy 

that are, at a minimum, consistent with the State’s policy and with paragraph (a) of this section.” States

and authorized tribes have considerable discretion as to how they address the minimum elements in 

their programs.

B. Comments That EPA Should Not Force States to Adopt New Policies or 

Regulations as a Result of the New Minimum Elements

Some commenters expressed that the only requirement should be that a state has an antidegradation 

policy not EPA mandating the minimum elements that must be contained therein. A commenter 

specifically said that “While EPA may have a role to ensure that state water quality standards meet the 

requirements of the Act and are being implemented, new regulatory requirements are not the 

appropriate approach to ensuring implementation of state anti-degradation programs.” One commenter 

provided an example of a state policy that pre-dates the CWA, and said that EPA should not be allowed 

to mandate that the state adopt a new policy or regulations to incorporate new minimum elements 

without a demonstration that the State's current policy is causing water quality problems as currently 

written and implemented, or is contrary to current federal law or regulations. EPA disagrees. The 

‘minimum elements’ listed in the proposal preamble were derived from the already existing 

requirements for state and tribal antidegradation policies and included the few additional requirements 

included in the proposal. EPA has authority under the CWA to promulgate regulations needed to

administer and implement the CWA in order to serve the purposes of the Act. See CWA section 501(a). 

Regulations may need to change in order to better meet the objectives of the CWA as new 

environmental challenges arise and new science is developed. EPA’s preamble to the proposed rule and 

final rule explain that the prior federal antidegradation requirements were not fully successful in 

ensuring that antidegradation is implemented consistent with the CWA. EPA has finalized regulatory 

revisions that are necessary to ensure that sound water quality management decisions are made 

nationally. Certain states may have fewer changes to make to their standards to be consistent with 

today’s final rule. For states and authorized tribes that currently have WQS that are consistent or mostly 

consistent with today’s rule, then EPA expects that any revisions to those water quality will have 

minimal burden on the state and minimal impact on the state or authorized tribe’s decision making 

process. EPA is ready to assist any state or authorized tribe in evaluating their currently applicable 

antidegradation requirements to determine whether and what revisions are necessary to comply with 

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the new requirements. EPA understands that any potential revisions may take time. Thus, the preamble 

to the final rule clearly explains “EPA’s expectation is that, where a new or revised requirement 

necessitates a change to state or authorized tribal WQS, such revisions will occur within the next 

triennial review that the state or authorized tribe initiates after publication of the rule.” 

A commenter also stated that EPA should work on moving the focus from individual discharges that 

might cause minimal localized degradation to a broader watershed-wide focus aimed at controlling all 

sources to a reasonable level in a manner that allows all of the applicable WQS to be met. EPA agrees in 

principle that a watershed focus on all sources of pollution can be extremely useful in helping to achieve 

standards. EPA’s final rule codifies the acceptance of a water body–by–water body approach where 

states wish to identify high quality waters on a more holistic basis. Some states have also chosen to 

adopt a de minimis threshold which allows them to focus on discharges that have more than a 

de minimis effect on water quality. However, EPA disagrees that a watershed approach is mutually 

exclusive of attention to individual discharges. For example, EPA has provided guidance on watershed 

approaches to permitting that still contain a focus on individual discharges: 

http://water.epa.gov/polwaste/npdes/basics/Watershed-Based-NPDES-Permitting.cfm. Whether 

antidegradation requirements are met by focusing on specific dischargers or at a broader watershed 

level is at the discretion of the states and authorized tribes and how they wish to write their 

antidegradation implementation methods. EPA has made it clear that antidegradation requirements 

apply to the water body itself and not to specific dischargers or discharges.

For additional discussion on Antidegradation Guidance and comments on how EPA should have issued 

more guidance rather than revised regulations, please see response essay 7.c.

C. Comments That EPA Should Clarify What the Requirements Are for “All CostEffective and Reasonable Best Management Practices for Nonpoint Source

Controls”

Some comments pointed out that the list of minimum elements of antidegradation implementation 

methods in the proposal preamble included: “Requirements for point and nonpoint sources: the state or 

tribe will ensure that there shall be achieved the highest statutory and regulatory requirements for all 

new and existing point sources and all cost-effective and reasonable best management practices for 

nonpoint source control when allowing a lowering of water quality.” The commenter expressed the view 

that this created confusion about whether there is a federal requirement to implement nonpoint source 

(NPS) control best management practices (BMPs). Per the commenter’s suggestion, EPA clarifies here 

that the requirements regarding controls for NPS pollution included in 40 CFR 131.12 do not create an 

obligation for states or authorized tribes to implement NPS controls if they have not chosen to impose 

such requirements themselves. Section 131.12(a)(2) does not require a State to establish BMPs for NPS

where such BMP requirements do not exist. EPA interprets section 131.12 (a)(2) as requiring States to 

adopt an antidegradation policy that includes a provision that will assure that all cost-effective and 

reasonable BMPs established under state or authorized tribal authority are implemented for NPS before 

the state or authorized tribe authorizes degradation of high quality waters by point sources.

See: February 22, 1994 Memo from Tudor Davies, “Interpretation of Federal Antidegradation Regulatory 

Requirement” 

(http://water.epa.gov/scitech/swguidance/standards/upload/2006_12_01_standards_antidegmemo.pdf), 

and EPA’s Water Quality Standards Handbook at 4.5 

(http://water.epa.gov/scitech/swguidance/standards/handbook/chapter04.cfm#section5) 

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For a discussion of what “cost-effective and reasonable best management practices for nonpoint source 

controls” means in the context of waterbody variances, please see response essay 8.g.v.

D. Comments regarding States’ and Authorized Tribes’ Responsibility 

Some comments stated that if EPA is going to (1) define what the implementation procedures must 

contain and then (2) approve or disapprove them, there will be little left of states' responsibility. EPA 

disagrees. The final rule does not require that states and authorized tribes adopt legally binding 

implementation methods that EPA would approve or disapprove. In addition, as discussed in section A 

of this response essay, the description of minimum elements of implementation methods in the 

preamble to the proposal reflected requirements that already existed for states’ and authorized tribes’ 

antidegradation policies (plus the elements that were proposed to be included in the final rule), so EPA’s 

definition of minimum elements did not in fact remove any flexibility from states and authorized tribes. 

Under the final rule, states and authorized tribes continue to have extensive responsibility and flexibility 

as to how they address the required elements of antidegradation. EPA will consider providing a final list 

of minimum elements to facilitate antidegradation implementation in future antidegradation guidance 

documents based on the final rule requirements.

E. Comments regarding Compliance with the Clean Water Act Section 316(a)

The preamble to the proposed rule included in the list of antidegradation implementation methods 

minimum elements: “The state or tribe will ensure consistency with Section 316 of the Act in cases that 

involve potential water quality impairment associated with thermal discharges.” EPA derived this 

element directly from already existing regulatory language at 40 CFR section 131.12(a)(4): “In those 

cases where potential water quality impairment associated with a thermal discharge is involved, the 

antidegradation policy and implementing method shall be consistent with section 316 of the Act.” EPA 

has explained its interpretation of the rule in the WQS Handbook at 4-2 and in the 1998 Advance Notice 

of Proposed Rulemaking (ANPRM). 

Section 316(a) regulations and implementation of those regulations are outside the scope of this rule. A 

commenter stated that with respect to alternative limits on discharges of heat under section 316(a) of 

the (CWA), EPA did not propose to change the actual wording of “the rule.” EPA agrees that this is true. 

EPA is not making any changes to the wording of any rules related to section 316(a).

Some commenters disagreed that state and tribal implementation methods should be required to 

ensure consistency with section 316 where there is potential water quality impairment from thermal 

discharges, and stated that there should be “no changes.” The commenter stated that the problem was 

not with the wording of the rule, but rather a handful of interpretations by EPA Regions suggesting that 

section 316(a) is “not an alternate to ordinary water quality-based limits but a stand-alone requirement 

that must be met in addition to complying with limits based on ordinary water quality criteria.” The 

commenter stated that these interpretations are at odds with section 316(a), which on its face is an 

alternative to ordinary water quality-based limits. Section 316(a) implementation is outside of the scope 

of this rulemaking. For information about EPA’s interpretation 40 CFR section 131.12(a)(4), see the WQS 

Handbook at 4-2 and the ANPRM.

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F. Comments That EPA Should Not Require Antidegradation Tier 2 Reviews for 

Impaired Waters

Some commenters stated that they were concerned “about the requirement in proposed § 131.12(b)(1) 

that State implementation methods must "ensure" that a state conducts an antidegradation review for a 

water body on its impaired waters list, if the water body exceeds the quality needed to achieve one of 

the uses specified in CWA § 101(a)(2).” To the extent the commenter implies that the proposal and final 

rule require Tier 2 review for all waters on the impaired waters list, EPA disagrees. The final rule does 

not require states and authorized tribes to conduct a Tier 2 review on all waters listed as impaired per 

CWA 303(d). Rather, the final rule requires that when identifying high quality waters, “the State shall not 

exclude a water body from the protections described in (a)(2) of this section solely because water 

quality does not exceed levels necessary to support all of the uses specified in section 101(a)(2) of the 

Act.” (emphasis added) This is not substantively different from the intent of the proposal but is different 

from the commenter’s characterization of the proposed rule. The final rule will not require that a state 

conduct Tier 2 review on waters listed on the impaired waters list just because they are on the impaired 

waters list. It would require that impairment of a water body cannot be the sole reason for excluding the 

water body from Tier 2 protection.

Some commenters also stated that it is inconsistent with the CWA to consider an impaired water to be 

high quality water and would be a misallocation of state resources to require an anti-degradation review 

for impaired water. They did not explain why it is inconsistent with the CWA to provide Tier 2 protection 

for a water that is also impaired for one or more parameters. EPA disagrees that conducting a Tier 2 

review on an impaired water body is inconsistent with the CWA and that it is a misallocation of state 

resources. State and authorized tribal “antidegradation policies” apply to all waters, including waters 

that are impaired for one or more parameters; at a minimum, Tier 1 of antidegradation applies to all 

waters of the U.S. It is possible for a water to be considered ‘high quality’ (for purposes of Tier 2 of 

antidegradation) and ‘impaired’ (by the 303(d) listing program) at the same time. For example, a water 

might be of high quality with respect to some chemical, physical, and biological parameters but impaired 

with respect to others. Tier 2 can provide protection for the high water quality that exists in the water 

body (e.g., assimilative capacity for some parameters), despite having impairments with respect to some 

parameters. This is fully consistent with the goals of the CWA. CWA section 101(a) includes the objective 

to “restore and maintain the chemical, physical and biological integrity of the Nation’s waters.” The 

potential for a water to be both high quality and impaired is evident in this section of the CWA. This goal 

can only be met by restoring the Nation’s waters and by maintaining the chemical, physical and 

biological integrity which has been achieved. Waiting to “maintain” water quality when a water body is 

completely unimpaired on every parameter would likely result in no waters eventually being restored. 

Therefore, it is in line with the CWA for States to allocate resources to meeting this objective of the 

CWA. In addition, states and authorized tribes have flexibility in allocating their resources for 

antidegradation protection. For example, a state or authorized tribe can incorporate a ‘de minimis’ 

concept into their implementation.

Some commenters stated that the proposed requirement at section 131.12(b)(1) is inconsistent with 

existing state policies, including those that have withstood legal challenge, and inconsistent with the 

position EPA has taken to defend such policies (citing Kentucky Waterways Alliance v. EPA, 540 F.3d 466 

(6th Cir. 2008) which upheld EPA approval of the provisions of Kentucky's antidegradation policy that 

exclude impaired waters from anti-degradation review). EPA acknowledges that the proposed 

requirement was (and the final rule requirement is) a shift in policy from EPA’s previous position and 

from some existing approved state policies. After careful consideration, EPA is changing this policy via a 

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notice and comment rulemaking. EPA has the authority to alter the regulations in the interest of 

administering the Act. EPA recognized the need to revise its regulations to meet the objectives in light of 

new challenges, information, and science.

Some commenters expressed concern that the proposed requirement at section 131.12(b)(1) would be 

inconsistent with state policies to encourage infilling and protect green space by placing additional 

barriers on discharges near impaired waters. EPA disagrees. The final requirement does not bar states 

from allowing discharges near impaired waters, but rather specifies that the water cannot be wholesale 

excluded from tier 2 protection solely because it is not meeting all of the uses specified in CWA section 

101(a)(2). EPA recognizes that multiple considerations, such as cross-media impacts, can be important in 

making decisions about how and how much to protect high water quality. The final rule allows for 

flexibility specifically to account for these kinds of complex decisions.

G. Comments That the Minimum Elements Should Be in Rule and Include More 

on Tier 1

Some commenters questioned why EPA was not including the minimum elements for antidegradation 

implementation methods in rule and should add some additional detail, particularly existing use 

protection. The elements derive from the elements of the regulation, which states and authorized tribes 

are already required to address in their antidegradation policies. Including such elements in regulation 

would be redundant of the regulation. EPA will consider providing a final list of minimum elements to 

facilitate antidegradation implementation in future antidegradation guidance documents based on the 

final rule requirements and whether or not additional detail, in the form of guidance, is necessary to 

address Tier 2 as well as Tier 1 and Tier 3. Because these minimum elements are derived from the 

regulatory requirements, if a state’s antidegradation implementation method does not address one of 

the elements, it would not be consistent with section 131.12 and EPA would have the authority to 

disapprove a legally binding implementation method or make an Administrator’s determination that 

new or revised WQS are necessary.

EPA received comments regarding Tier 1, however, the proposal and final rule focus on enhancing the 

protection for Tier 2 waters. Thus, comments related to Tier 1 are outside the scope of this rulemaking.

Not addressing Tier 1 in no way reflects an intention that Tier 1 is not important or is not a current 

requirement of the regulations. EPA agrees that additional guidance on implementing Tier 1 existing 

uses protection would be useful. As mentioned earlier, EPA will consider developing additional guidance 

on Tier 1 once the final regulations are published.

H. Comments regarding Who Conducts the Analysis of Alternatives and the 

Term “Practicable”

For a response to comments regarding whether States really have the experience to conduct an analysis 

of alternatives consistent with section 131.12(a), please see response essay 7.e.ii, section D.

For a response to comments regarding the definition of “practicable” and the scope of the analysis of 

alternatives, please see response essay 7.e.ii, sections K and O.

A commenter suggested that EPA require that the state evaluate only “reasonable and cost-effective 

measures that would reduce or eliminate the potential degradation” rather than requiring a complex 

analysis of alternatives. For a discussion on the types and range of alternatives that EPA expects to be 

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considered, please see response essay 7.e.ii, in particular sections K and O. For a discussion of whether 

this analysis of alternatives is complex and the burden it may impose, please see response essay 7.e.ii, 

section F.

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Essay 7.g.iii – Antidegradation Minimum Elements: Suggested 

Changes/Revisions to Minimum Elements

A. Comments on State Specific Cases as Examples of Ineffective EPA Regulation

The U.S. Environmental Protection Agency (EPA) considered the comments describing and characterizing

federal regulatory requirements, EPA guidance, and court cases related to antidegradation. EPA also 

considered comments citing a specific state as an example of EPA’s current antidegradation regulatory 

provisions having not been effective or successfully implementing the Clean Water Act (CWA) 

antidegradation policy. Today’s rule is a national rule. Comments on the quality of specific state CWA 

programs (e.g., water quality standards [WQS], CWA section 402 permitting, CWA section 303(d) listing) 

are outside the scope of this rulemaking. EPA will work with states and stakeholders on specific state 

issues through its regional offices outside of this national rule context. As to the 2012 Florida Wildlife 

Federation rulemaking petition discussed in the comments, EPA is considering the petition and will 

respond to that petition directly. As discussed above, the petition (which specifically relates to Florida’s 

WQS) was outside the scope of this national rule. EPA did not propose promulgating WQS for specific 

states through this rulemaking and is not doing so in the final rule.

EPA agrees with commenters’ observation that some state and tribal implementation methods that 

have not been adopted as legally binding have attempted to undermine or modify the adopted and EPA 

approved antidegradation policy. While EPA’s final rule does not require states and tribes to adopt 

legally binding implementation methods, it does require public participation and accountability on any 

changes to implementation methods. In addition, implementation methods that are not approved by 

EPA are not applicable WQS for CWA purposes. Therefore, to the extent that any antidegradation 

implementation methods undermine the applicable CWA antidegradation policy, EPA would potentially 

have a basis to object to authorizations for regulated activities (e.g., a National Pollutant Discharge 

Elimination System (NPDES) permit) that are not consistent with the applicable antidegradation WQS to 

or make an Administrator’s Determination. Any administrator’s determination would be considered on a 

case-by-case basis.

Comments regarding whether a specific state’s antidegradation WQS need to be clustered in one 

section of the state’s WQS are outside the scope of this rulemaking, as EPA did not propose or finalize a 

requirement that states must group their antidegradation requirements in one section.

B. Comments on Specific State Situations Related to 303(d) Listing and 

Antidegradation

Comments related to specific CWA section 303(d) listing state practices and antidegradation, and 

related to establishing baseline assimilative capacity for Tier 2 waters are beyond the scope of this 

rulemaking. This rulemaking is focused solely on the identification of high quality waters and analyzing 

alternatives whenever conducting a Tier 2 review and on the public involvement needed on these 

decisions and when developing and/or revising antidegradation implementation methods. EPA’s rule did 

not propose or solicit comment on regulations regarding listing impaired waters based on 

antidegradation. In addition, comments regarding EPA’s actions on state and tribal 303(d) lists are 

outside the scope of this rulemaking. EPA will consider developing guidance on additional topics related 

to antidegradation that were not addressed in this rulemaking in a subsequent effort after the final rule 

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is published and will be available to work with specific states through its regional offices outside the 

context of this national rulemaking. 

C. Comments regarding Antidegradation and Point Sources and Nonpoint 

Sources

EPA agrees with a comment stating that because the antidegradation policy regulates and protects 

against overall waterbody ambient aquatic resource degradation, not merely individual sources of 

degradation, antidegradation WQS are not based upon the number of discharges nor whether the 

discharge is point source or nonpoint sources (NPS). EPA agrees that antidegradation requirements 

relate to whether the ambient water quality of water bodies are degraded (lowered) by any and all of 

the pollutant loads into the water bodies, regardless of whether the pollution load is a point source or 

NPS, and regardless of whether the pollution sources are permitted or not permitted. Antidegradation 

requirements apply to all water bodies. However, some states have chosen to prioritize when they 

conduct Tier 2 reviews by establishing de minimis exceptions and conducting Tier 2 reviews only when 

the lowering of water quality exceeds “de minimis.” These de minimis exceptions do not mean that 

antidegradation requirements to not apply to those waters.

D. Comments That Alternatives Analyses Are Not Necessary

A commenter stated that “no revisions should be made to section 131.6(d) and consequently 

alternatives analyses are not necessary.” EPA disagrees that a requirement for an analysis of alternatives 

is unnecessary. EPA is not revising section 131.6(d), which specifies that states and authorized tribes 

must submit their antidegradation policies consistent with section 131.12. However, the requirement to 

conduct an analysis of alternatives does not originate in section 131.6(d). Rather, the requirement to 

conduct an analysis of alternatives stems from section 131.12(a)(2), which prior to this rule specified, 

among other requirements, that in order to allow a lowering of high water quality, a state or tribe must 

make the finding that the lowering is “necessary to accommodate important economic or social 

development in the area in which the waters are located.” EPA interprets the word “necessary” to mean 

that alternatives to the lowering of water quality have been considered. The final rule does not revise 

section 131.6(d), but it does add detail to the requirements for states’ and tribes’ antidegradation 

policies at 131.12(a)(2), including the analysis of alternatives, which is now a required part of Tier 2 

review. For additional information on EPA’s decision to include the analysis of alternatives requirement 

in the regulation, please see the Preamble to the final rule and Response Essays 7.e.i, 7.e.ii, 7.e.iii, and 

7.e.iv. 

E. Comments That EPA Should Include More Specifics on Various Topics in the 

List of Minimum Elements, or Should Require More Specifics in State Water 

Quality Standards

EPA received comments requesting that EPA include more items, or more specifics about existing items, 

in the list of implementation methods minimum elements that it had provided in the preamble to the 

proposal. Commenters offered many specific reasons for suggesting these items. Some commenters 

suggesting additional items stressed the need to provide states and authorized tribes with additional 

information or guidance on how to implement antidegradation better. The suggestions included:

– Include more specific language about certain minimum elements EPA had listed:

o Specific language on Tier 2 socioeconomic review

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o Specific language on how assurances that requirements for all new and existing point 

sources and cost-effective and reasonable best management practices (BMP)s) have been 

addressed in Tier 2 review

o Specific language on protection of existing uses

o Specific language on identification and protection of Outstanding National Resource 

Waters (ONRWs) 

– Include minimum elements for:

o Establishment of baseline antidegradation assimilative capacity of Tier 2 and Tier 2.5 

waters

o Establishment on a limit on the cumulative degradation of the baseline assimilative 

capacity of Tier 2 and Tier 2.5 waters that could be allowed without Tier 2 review (because 

it is considered ‘de minimis’) 

o Establishment of an antidegradation impaired waters review methodology consistent with 

CWA section 303(d) and Title 40 of the Code of Federal Regulations (CFR) section 130.7

EPA disagrees that these suggested additions should be included as minimum elements. EPA derived the 

list of minimum elements in the proposal preamble from the fundamental elements required by the 

regulation (including those proposed to be added to the regulation.) The commenters’ suggestions go 

beyond the requirements of the WQS regulation at 40 CFR section 131.12 and the requirements that 

were proposed to be added (and finalized), and therefore EPA found it is not reasonable to list these 

additional elements as “minimum” elements of antidegradation implementation methods. EPA 

recognizes that implementation methods which include these elements are likely to be stronger and 

more protective of high quality waters. Therefore, EPA encourages states and authorized tribes to 

consider including these items in their implementation methods, in addition to the minimum elements.

States and authorized tribes may include these elements in their implementation methods at their 

discretion. EPA will consider providing additional discussion or examples on how a state or authorized 

tribe can fulfill the requirements of the final rule’s section 131.12(b), which may include some of the 

suggestions provided by commenters.

Commenters stated that EPA must clarify 40 CFR section 131.12 by requiring state WQS list the state 

pollution controls that must be considered, such as the following:

a. Implement new source performance standards (NSPS) on all new and existing point source 

discharges in the watershed of the waterbody.

b. Require more stringent effluent limitations, including lowering effluent limitation levels of all 

point sources discharges in the watershed of the waterbody to actual current loadings of the 

discharge(s).

c. Order the point or method of discharges changed.

d. Limit the duration or volume of discharges.

e. Require all new and existing stormwater management systems discharging within the 

watershed of the water body achieve at least 95% reduction of the average annual load of 

pollutant(s) at issue required by Fla.Admin.Code R. 62-25.025(9).

f. Regulate the water quality affects of water quantity uses which degrade the baseline 

assimilative capacity for the subject assimilative capacity water quality parameter.

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g. Require NPDES municipal separate storm sewer system (MS4) permits for all stormwater 

discharges that are a significant contributor within the watershed of the pollutant at issue in the 

waterbody.

h. Implement stricter effluent limitations on point source stormwater discharges in the 

watershed of the waterbody, including requiring clear, specific and measurable performance 

standards in NPDES MS4 permits that are enforceable and prohibit violation of WQS.

I. Implement stormwater control measures within the watershed of the subject waterbody 

require redeveloped sites to retrofit existing stormwater systems.

j. Implement stormwater control measures in MS4 permits which require the identification of 

stormwater pollution hotspots within the watershed of the subject water body, and the use 

pollution prevention actions in the identified hotspots.

k. Require local governments in the watershed of the waterbody with stormwater management 

systems to exercise land use control measures to reduce the pollutant load at issue, including 

runoff volume reduction, peak flow reduction, and increasing runoff treatment levels.

l. Regulation and control activities which have adverse cumulative and secondary impacts on 

surface water quality, including requiring triennial septic tank inspection and necessary 

retrofitting within the watershed and springshed of the waterbody.

m. Cost effective and reasonable tightening up of BMPs on NPS within the watershed of the 

waterbody for the pollutant at issue.

EPA disagrees that these suggested items should be required state pollution controls that must be 

considered, EPA assumes in the context of Tier 2 analysis of alternatives. The commenters suggest a 

level of specificity to the federal requirement for analysis of alternatives that EPA views as overly 

prescriptive in light of the cooperative federalism inherent in the CWA. Furthermore, the alternatives 

that are practicable to consider are situation-specific, depending on the type of discharge and the type 

of water body. Not all of the items on the list would be relevant to each situation that states and 

authorized tribes encounter, and therefore a requirement to consider each and every item on the list 

would be inappropriate. Finally, many of the items on the list go beyond the authority of the WQS 

regulation at Part 131, for example some deal specifically with NPDES requirements, or with technologybased effluent limitations, or with land use decisions. Therefore, the regulation at Part 131 is not the 

appropriate place to consider such requirements.

F. Comments That EPA Should Carve out Exceptions to Antidegradation 

Review

For a response to comments regarding exceptions to Tier 2 review despite some increase in pollutant 

loadings so that States can implement their water quality programs in an efficient and effective manner, 

please see the preamble to the final rule at section D and response essay 7.i. 

A commenter argued that EPA should specifically allow for exceptions to Tier 2 review for certain kinds 

of projects with evident social and/or economic benefit. EPA disagrees. The CWA does not provide for 

an explicit cost/benefit analysis when implementing WQS. Courts have provided a basis for states and 

authorized tribes to efficiently use resources when there is a de minimis or trivial impact on water 

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quality itself. The point of Tier 2 review is to provide a mechanism for states and authorized tribes to 

make informed, publically transparent decisions about allowing lower water quality, based partially on 

social or economic considerations. Bypassing Tier 2 review would remove the opportunity for full public 

consideration of the socioeconomic importance of the proposed activity and therefore, even 

consideration of de minimis exceptions should be made in consultation with the public. 

Finally, although the comment referred to “exceptions when antidegradation review is not required,” 

EPA notes that certain antidegradation protections (e.g., Tier 1) always apply, even if a state has chosen 

to provide de minimis exceptions for Tier 2 review.

G. Comments That EPA Should Not Provide Minimum Elements and Describe 

Their Purpose as “Facilitation” in Preamble Language

For a response to comments regarding the appropriateness of providing minimum elements for 

implementation methods in preamble, please see response essay 7.g.ii, sections A and B.

H. Comments That EPA Should Be Clear What Is Required in Implementation 

Methods

A comment stated that while the minimum elements provided in the preamble to the proposed rule 

discusses five issues (and four sub-issues) that implementation methods must address, the actual 

regulatory language proposed only includes clear instruction on two issues. The comment continued 

that if EPA wants to make clear what is required in implementation methods, those requirements should 

be included in its regulations. EPA disagrees that additional regulatory language is necessary to track 

with those minimum elements. EPA’s final rule provides additional regulatory language regarding some 

aspects of Tier 2 antidegradation review that EPA chose to target for rulemaking at this time in order to 

strengthen Tier 2 protection. 40 CFR 131.12(b) requires that implementation methods be, at a 

minimum, “consistent with the State’s policy and with” section 131.12(a). Although EPA did not provide 

specific revised regulatory language (e.g., Tier 1) on the other items listed as minimum elements, each of 

these is included as a requirement of the antidegradation policy at section 131.12(a) and thus must be 

addressed by state and authorized tribe implementation methods. States and authorized tribes continue 

to have considerable discretion in how they address the elements of their policy and section 131.12(a) 

as long as they do not undermine either.

I. Comments That Implementation Methods with Minimum Elements Are 

Water Quality Standards

Commenters stated that since many of the minimum elements listed in the preamble to the proposal 

address when and how antidegradation is applied, implementation methods with these elements are a 

WQS. EPA partially agrees and partially disagrees. While EPA’s view is that antidegradation 

implementation is likely to be more transparent and more accountable if a state or authorized tribe 

adopts its implementation methods as legally binding, adopting the methods is not required. New or 

revised antidegradation implementation methods that are not legally binding are not considered new or 

revised WQS. See EPA’s frequently asked questions (FAQs) on “What is a New or Revised WQS under 

CWA 303(c)(3)” http://water.epa.gov/scitech/swguidance/standards/cwa303faq.cfm. Please see 

response essay 7.f.i for further discussion on adoption of Antidegradation Implementation Methods.

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A commenter suggested that the proposed regulatory changes regarding identification of waters for Tier 

2 protection and regarding analysis of alternatives should be included as part of states’ and authorized 

tribes’ antidegradation policies. EPA agrees that the additional requirements must be part of the 

antidegradation policy and thus be part of the WQS themselves. The final rule includes the requirements 

addressing identification of high quality waters and conducting an analysis of alternatives and selection 

of an alternative as part of section 131.12(a), which provides specific requirements of antidegradation 

policies rather than just part of the antidegradation implementation methods. Antidegradation policies 

are new or revised WQS that must be reviewed and approved or disapproved by EPA. EPA’s final rule 

revised section 131.12(b) from the proposal to simply say that implementation methods must be 

consistent with the state’s or authorized tribe’s antidegradation policy and section 131.12(a). As a result, 

it is unnecessary for EPA to require that all implementation methods be legally binding. However, where 

they are binding, section 131.5(a)(3) makes clear that EPA has the authority to review and approve or 

disapprove the implementation methods.

Commenters also stated that proposal’s focus on one component of Tier 2 review (analysis of 

alternatives) was misleading, and that the discussion of Tier 2 reviews needs to be expanded to address 

socio-economic review, requirements for point sources, and BMPs for NPS. EPA agrees that Tier 2 

reviews consist of several parts as described in 131.12(a)(2), not only the alternatives analysis. The 

minimum elements in the proposal preamble and the regulation at 131.12(a)(2) makes this clear. 

However, the fact that the final rule only adds more detail to the alternatives analysis component does 

not diminish the importance of the other aspects. The other aspects are still required, as they always 

have been. The final rule makes clear that states’ and authorized tribes’ findings that a lowering is 

necessary depends on both an analysis of alternatives and an analysis related to economic or social 

development. The commenter also stressed the importance of implementation methods addressing not 

only Tier 2 reviews, but existing uses and ONRW protection. The proposal preamble did include points 

about existing uses and ONRW protection among the minimum elements.

EPA also agrees that implementation methods must also address protection for existing uses, cost 

effective and reasonable BMPs and ONRWs, not just Tier 2 protection. The proposal preamble listed 

those among the ‘minimum elements’ of implementation methods. As discussed in response essay 7.g.ii, 

section G, Because these minimum elements are derived from the regulatory requirements, if a state’s 

antidegradation implementation method does not address one of the elements, it would not be 

consistent with section 131.12 and EPA would have the authority to disapprove a legally binding 

implementation method or make an Administrator’s determination that new or revised WQS are 

necessary. 

J. Comments regarding Antidegradation as a Basis for 303(d) Listing of 

Impaired Waters

EPA received comments on both sides of the question of whether antidegradation is a basis for CWA 

303(d) listing of impaired waters. EPA explicitly states in the preamble to the final rule that 

antidegradation requirements apply to a water body regardless of source and thus it is inaccurate to 

consider antidegradation requirements to apply only to point sources receiving NPDES permits.

However, comments related to CWA 303(d) listing and antidegradation are beyond the scope of this 

rulemaking which is focused solely on the identification of high quality waters and analyzing alternatives 

whenever conducting a Tier 2 review and on the public involvement needed on these decisions and 

when developing and/or revising antidegradation implementation methods. EPA’s rule did not propose 

or solicit comment on regulations regarding listing impaired waters based on antidegradation. EPA will 

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consider developing guidance on additional topics related to antidegradation that were not addressed in 

this rulemaking in a subsequent effort after the final rule is published. EPA’s 2014 Integrated Reporting 

Guidance contains some discussion on the topic of 303(d) listing and antidegradation: 

http://water.epa.gov/lawsregs/lawsguidance/cwa/tmdl/2014-memo.cfm. 

K. Comments regarding the Circumstances in Which Antidegradation is 

Considered in 303(c) Reviews

EPA received comments that EPA should “explicitly state in its regulations the limited circumstances that 

antidegradation is considered in its 303(c) reviews.” When reviewing new or revised WQS, EPA 

evaluates whether it meets the requirements of the applicable regulatory provisions. In determining the 

applicable regulatory provisions, EPA must first determine whether the new or revised WQS is a new or 

revised designated use, new or revised water quality criteria, new or revised antidegradation 

requirement, or a new or revised WQS variance. EPA may evaluate a state or authorized tribe’s existing 

WQSs to inform that decision. However, EPA’s authority to review and approve or disapprove a WQS is 

limited to those provisions that meet are new or revised and legally binding, as explained in EPA’s FAQs

“What is a New or Revised WQS under CWA 303(c)(3).” 

http://water.epa.gov/scitech/swguidance/standards/cwa303faq.cfm. EPA agrees with the commenter 

that when reviewing a new or revised designated use or water quality criteria, EPA does not re-review a 

State’s antidegradation policy and implementation methods once EPA approved those antidegradation 

provisions. EPA notes, however, that the EPA Administrator has the authority to make a determination 

that new or revised WQS are necessary. This is the case even when a state or authorized tribe has a 

long-standing regulation in place. EPA disagrees with the commenter that section 131.5(a)(3) needs to 

be revised to make this clear. The provisions at section 131.5 are intended to provide EPA’s authority 

under CWA 303(c)(4)(A) and 303(c)(4)(B). Because the Administrator has the authority to make a 

determination that new or revised WQS are necessary at any time, even when there are no new or 

revised WQS, it would be inappropriate to revise this section. EPA’s FAQ mentioned in this paragraph 

makes sufficiently clear the limitations of EPA’s authority when reviewing WQS under CWA 303(c)(4)(A).

L. Comments regarding the Scope of Implementation Methods

Some commenters assumed that EPA’s rule targeted the application of antidegradation policies during 

“permit reviews.” Commenters stated that in the absence of guidance on how antidegradation policies 

are applied outside of permitting, neither EPA, the public, nor States will have understanding on how to 

review, approve, develop, or comment upon other implementation methods. Commenters thus 

requested that EPA clarify in the rules the scope of implementation methods that are envisioned.

EPA has explicitly stated in section B of the preamble to the final rule that WQS, including 

antidegradation requirements, apply to a water body regardless of whether the source of pollution is 

point or NPS and regardless of whether a state or authorized tribe has chosen to control NPS activities. 

However, EPA agrees with commenters that further guidance is needed to inform the public, coregulators, and regulated entities about how antidegradation should apply in a variety of contexts. EPA 

is not providing this clarification in this rulemaking, but the Agency intends to provide additional 

guidance on antidegradation once the final rule is published and will consider this issue along with a 

wide variety of other issues when planning its guidance. 

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M. Comment That EPA Has No Basis to Require States to Implement 

Antidegradation in a Particular Way

For a response to comments that EPA has no basis to require states to implement antidegradation in a 

particular way and that the only constraint on states should be that the states may not act in a manner 

inconsistent with the Act, please see response essay 7.g.ii, sections A and B and essay 7.m. 

N. Comments That Total Maximum Daily Loads and Wasteload Allocations Are 

Subject to Antidegradation Review

EPA disagrees with comments saying “EPA must clarify that ...water-quality based effluent limitations 

(WQBELs) must be based upon TMDLs and WLAs subject to antidegradation review and the 

antidegradation policy of the CWA.” As EPA articulated in the proposal preamble, “Antidegradation 

reviews are applicable to revisions to effluent limitations based on a TMDL, wasteload allocation, or 

water quality standard, but they are not required for revisions to a TMDL, wasteload allocation, or water 

quality standard.” (citing Native Village of Point Hope v. U.S. Envtl. Prot. Agency, No. 3:11-cv-00200-

TMB, slip op. at 24-25 (D. Alaska Sept. 14, 2012).) Total maximum daily loads (TMDLs) and wasteload 

allocations (WLAs) themselves are not subject to antidegradation review or antidegradation policies 

because they do not directly affect water quality. In contrast, permits, licenses, or other authorizations 

that implement TMDLs and WLAs and that allow effects to water quality are generally subject to 

antidegradation review.

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Essay 7.g.iv – Antidegradation Minimum Elements: Comments on 

Acceptability of Existing State Antidegradation Implementation 

Measures

No comments are assigned to this issue category, and thus no response is necessary.

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Essay 7.h – Antidegradation: Effect on States for Which EPA Has 

Promulgated Antidegradation Implementation Measures

No comments are assigned to this issue category, and thus no response is necessary.

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Essay 7.i – Antidegradation: De Minimis

A. EPA Should Not Restrict De Minimis

The U.S. Environmental Protection Agency (EPA) received many comments regarding de minimis 

exemptions to a Tier 2 review. 

EPA is not making any regulatory revisions addressing de minimis exemptions because these comments 

are beyond the scope of this rulemaking. EPA did not propose any regulatory revisions or solicit 

comment on de minimis exemptions. Please see the preamble to the final rule which provides a 

discussion of EPA’s current stance on de minimis exemptions to Tier 2 reviews based on recent case law.

B. EPA Should Require States and Authorized Tribes to Establish Baseline 

Assimilative Capacity in Legally Binding Methods

Commenters requested that EPA amend Title 40 of the Code of Federal Regulations (CFR) section 131.12 

to require states and authorized tribes that adopt antidegradation implementation methods by rule to 

also establish a baseline antidegradation assimilative capacity of Tier 2 and Tier 2.5 waters for 

recreational and aquatic life uses. The commenter also requested that EPA amend section 131.12 to 

require these states and authorized tribes to establish a cap on the cumulative degradation of the 

baseline assimilative capacity. 

Comments requesting EPA require baseline assimilative capacity and cumulative caps are outside the 

scope of this rulemaking. EPA did not propose nor solicit comments on this issue. The preamble to the 

final rule provides a discussion of EPA’s current stance on de minimis exemptions to Tier 2 reviews 

based on recent case law.

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Essay 7.j – Antidegradation: Tier 3/ONRWs

A comment suggested that the U.S. Environmental Protection Agency (EPA) should revise the water 

quality standards (WQS) regulations to encourage more frequent use of Tier 3 classification for 

outstanding national resource waters (ONRWs). While EPA agrees that states could better utilize Tier 3 

antidegradation protection, these comments are beyond the scope of this rulemaking, which is focused 

on targeted revisions to the antidegradation Tier 2 requirements. EPA did not propose or solicit 

comment on regulatory provisions for Tier 3; therefore, EPA is not making any revisions in the final rule 

to the Tier 3 provisions. The preamble generally discusses ways that states and authorized tribes can 

facilitate public involvement, such as a petition process, which could also be used for Tier 3 protection 

decisions. EPA will consider addressing Tier 3 classifications, including considering ways to encourage 

more frequent use of them, when developing subsequent guidance on antidegradation following this 

final rule.

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Essay 7.k – Antidegradation: Linkages with Great Lakes Initiative 

Provisions

A. General

The U.S. Environmental Protection Agency (EPA) agrees with a commenter stating that the requirements 

for antidegradation for the Great Lakes (Title 40 of the Code of Federal Regulations (CFR) Part 132, 

Appendix E) are not applicable to dischargers outside of the Great Lakes.

B. Requirements Go beyond the Scope of Alternatives within the Control of the 

Discharger

A commenter stated that EPA’s proposed requirements for analysis of alternatives in Tier 2 review 

would go “beyond the scope of alternatives within the control of the discharger.” EPA disagrees with the 

comment. The final rule contains a similar requirement to that proposed: “Before allowing any lowering

of high water quality, pursuant to (a)(2) of this section, the State shall find, after an analysis of 

alternatives, that such a lowering is necessary .... The analysis of alternatives shall evaluate a range of 

practicable alternatives that would prevent or lessen the degradation associated with the proposed 

activity...” The final rule text requires evaluation of “a range of practicable alternatives” (emphasis 

added). If a discharger is preparing an analysis of alternatives for a state’s or authorized tribe’s 

consideration as part of a Tier 2 review, the discharger would analyze alternatives that are practicable

(practicable is defined at 40 CFR 131.3(n) as “technologically possible, able to be put into practice, and 

economically viable”). States and authorized tribes remain ultimately responsible for making findings to 

allow degradation and for basing their decisions on adequate analyses. If the state or authorized tribe 

deems an initial analysis of alternatives insufficient to support a finding that a lowering of high water 

quality is “necessary,” it can request additional analyses of alternatives from the permit applicant or 

other entities. There may be other practicable alternatives to consider aside from what the discharger 

itself considered. A state or authorized tribe can also obtain information on common practicable 

alternatives appropriate for a proposed activity from additional existing resources.1

C. EPA Should Promulgate the Great Lakes Initiative Requirements Nationally

A commenter requested that EPA consider promulgating the requirements in 40 CFR part 132 and 

“Water Quality Guidance for the Great Lakes System” (the Great Lakes Initiative [GLI]) in 131.12 to 

provide consistent antidegradation decisions and implementation methods nationwide. Although EPA 

considered the GLI when developing revisions to the nationally applicable rule, EPA consciously chose 

not to promulgate the requirements of the GLI nationally. The GLI rule was developed specifically to 

address issues in the Great Lakes, and as such, had more specificity in its requirements. While EPA 

agrees that some degree of national consistency among states’ and authorized tribes’ antidegradation 

implementation is necessary in order to be consistent with the Clean Water Act (CWA), the water quality

standards (WQS) regulations at 131 are intended to be broadly applicable across the nation to allow 

states and authorized tribes to determine the best way to protect waters in their jurisdiction consistent 

 

1 E.g., EPA’s Municipal Technologies website, which presents technology fact sheets to assist in the evaluation of 

different technologies for wastewater (http://water.epa.gov/scitech/wastetech/mtb_index.cfm) 

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with the CWA and Part 131. As such, the final rule does not contain as detailed requirements as in the 

GLI. The antidegradation requirements of the final rule are different from but are not inconsistent with 

the more detailed requirements in the GLI. States and authorized tribes with waters covered under the 

GLI continue to be subject to that rule, as well as to today’s final rule consistent with section 131.6. For 

example, when conducting a Tier 2 analysis for a water body covered by the GLI, the analysis of 

alternatives would need to consider a range of practicable alternatives that would prevent or lessen the 

degradation associated with the proposed activity (per today’s rule), the antidegradation demonstration 

would need to specifically include pollution prevention alternatives analysis and alternative or enhanced 

treatment analysis (per the GLI), and when the analysis of alternatives identifies one or more practicable 

alternatives, the State shall only find that a lowering is necessary if one such alternative is selected for 

implementation (per today’s rule).

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Essay 7.l – Antidegradation: General Comments

A. General Overall Comments

The U.S. Environmental Protection Agency (EPA) considered commenters’ recognition of the importance 

of antidegradation implementation, and shares commenters’ concerns that some states and authorized 

tribes have not implemented antidegradation adequately in the past, as explained in the advance notice 

of proposed rulemaking (ANPRM) and preamble to the proposal. 

Comments suggested that EPA add a purpose statement to explain the goal of 131.12, such as “The 

purpose of the antidegradation provisions is to ensure that the assimilative capacity of the nation’s 

waters is allocated in a thoughtful, transparent manner, with decisions supported by a sound technical 

record.” EPA agrees in a broad sense regarding the purpose of antidegradation. There are also many 

other ways to articulate the purpose of 131.12. EPA’s view is that the preamble to the final rule 

articulates the purpose to the extent necessary, particularly considering the existence of other EPA 

documents describing antidegradation in a broad sense (e.g., Water Quality Standards [WQS] Handbook, 

ANPRM).

Comments encouraged EPA to discuss climate change impacts in preamble discussion on 

antidegradation implementation, because climatic factors make assimilative capacity of high quality 

waters an even more important state resource to protect. EPA agrees with these comments and has 

included language about climate change in the preamble.

Comments disagreed that EPA’s statement that the nation’s waters face increasing stress from 

anthropogenic influences serves as a basis to revise the antidegradation portion of the WQS regulation. 

Some commenters stated that anthropogenic impacts on water quality are not necessarily greater now 

than in the past, and stated that water quality has improved since the enactment of the Clean Water Act 

(CWA) because of the implementation of regulations such as antidegradation. They stated that the fact

that discharges do exist and that new industries and sources will occur in the future is not evidence of a 

failed or inadequate antidegradation regulation. EPA disagrees. Commenters provided no evidence for 

their assertion that waters are not facing increasing anthropogenic impacts. The comments provided no 

evidence to refute the fact that some waters actually have degraded over time. EPA agrees that water 

quality has improved in many cases due to the CWA and implementing regulations; however, water quality 

problems remain, and some are getting worse. In the preamble to the proposal, EPA said that the number 

of waters identified as impaired continues to grow. Data on waters identified as impaired on a state-bystate basis via the 303(d) lists are publicly available, and can be searched to identify current reports and 

reports from previous reporting cycles. Please visit http://www.epa.gov/waters/ir/index.html. Scientific 

literature explores the increasing stresses on water quality as well. For example, the USGS Circular 1350 

reported on a comprehensive national analysis of nutrients in streams and groundwater from 1992 

through 2004 http://water.usgs.gov/nawqa/nutrients/pubs/circ1350/). The report states that “[d]espite 

major Federal, State, and local efforts to control point and non-point sources and transport of nutrients, 

concentrations of nutrients have remained the same or increased in many streams and aquifers across 

the Nation since the early 1990s.” 

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Comments also disagreed that EPA’s statement that the number of waters identified as impaired 

continues to grow serves as a basis to revise the antidegradation portion of the WQS regulation. They

said that the growing numbers of waters listed as impaired is most likely a reflection of increased and 

more widespread surface water monitoring by the states, and increasingly stringent WQS and section

303(d) listing protocols, not a failure of state antidegradation policies. EPA’s preamble statement did not 

attribute the increasing number of impaired waters solely to deficient antidegradation implementation. 

EPA does not disagree that the increasing number of waters listed as impaired has many causes, 

including the causes cited (e.g., monitoring has improved, assessment and modeling tools have 

improved, WQS have become more stringent.) EPA’s preamble statement did not attribute the 

increasing number of impaired waters solely to deficient antidegradation implementation. EPA 

appreciates state and authorized tribal efforts to improve monitoring, assessment, and modeling, and to 

adopt more stringent WQS. All of these will contribute to better protection of water quality. However, 

the increased stress on water bodies from pollution is a factor in the increased numbers of waters on 

the impaired waters lists. Therefore, EPA found it is reasonable for EPA to use the increasing number of 

impaired waters as a basis for strengthening the Tier 2 regulations. EPA’s final rule represents an effort 

to strengthen the WQS regulations to facilitate efforts to protect high quality waters. For more 

discussion, see response essay 7.b.

Some commenters were concerned with the use of the term “policy” within the regulation because it 

could be misinterpreted and requested that EPA stop using that term in rule. EPA recognizes that the 

terminology can be confusing, for example, EPA’s national regulation describes “policy” as legally 

binding, while some states’ “antidegradation policy” is non-binding implementation that supplements 

the state’s antidegradation regulatory requirements. Today’s preamble clarifies what EPA means by 

“antidegradation policy” and “antidegradation implementation methods.” 

EPA recognizes that some commenters appreciate EPA’s effort to improve antidegradation 

implementation, but think that EPA’s proposal was not stringent or specific enough to be useful, or that 

it would have little effect. The final rule provides a balance between adding more specificity to a few of 

the specific antidegradation requirements while allowing for state and authorized tribal flexibility.

Some comments urged EPA to take a more holistic approach in this and other regulations, “one which 

employs less separation, categorization, and determination of quality with regard to individual water 

bodies” rather than focusing on ‘water bodies.’ Comments pointed to the concept of hydrologic 

connectivity, and gave the example that “[i]f a body of water identified as “high quality” shares relatively 

close hydrological connections with substantially more degraded bodies of water, one could logically 

conclude that to improve the quality of the degraded bodies of water would, by extension, enhance the 

quality of the body of water deemed more pristine.” They also pointed out that nonpoint source (NPS) 

pollution is significant and evidences the need to broaden the scope of water quality improvement 

efforts. While EPA agrees to a certain extent that in many cases, water bodies are hydrologically 

connected to one another, and that NPS pollution is a major source of degradation, the comments are 

outside the scope of this regulatory revision. EPA did not propose and is not finalizing any changes to the 

regulation regarding how ‘water bodies’ are considered individually or in a holistic, interconnected 

manner.

Comments suggested that instead of revising the national regulation, EPA should first attempt to work 

closely with states that are not complying with the antidegradation requirements to see if the problems 

could be corrected without imposing national requirements. Some commenters suggested that EPA 

could use other administrative tools to bring these states up to par. For example, they suggested 

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working collaboratively on a shared “vision” or “framework” for antidegradation implementation as they 

have for total maximum daily loads (TMDLs) and nutrient criteria and using grant funding and technical 

assistance to target particular programs. EPA agrees that working together for a shared “vision” or 

“framework” can be useful for articulating expectations, however, those do not culminate in legally 

binding requirements beyond those that the states and authorized tribes themselves choose to adopt. 

EPA agrees that grant funding can be targeted to improve programs, but this is most appropriate when 

only one or a small number of states or tribes needs assistance, and EPA does not view lack of funding as 

the primary roadblock towards states and authorized tribes implementing antidegradation effectively. 

EPA agrees that technical assistance can be useful, and does plan to provide an update to the WQS 

Handbook antidegradation section after publication of the final rule. For more information, see 

response essay 7.c.

B. Public Involvement

Comments requested that EPA require public participation standards to be applied to the process of 

designation of high quality waters as well as to any determination to remove high quality waters from 

Tier 2 protection. EPA agrees that public involvement is important for decisions about whether Tier 2 

protection will be afforded to a water. The final rule specifies a requirement for public involvement

where states and authorized tribes use a water body-by-water body approach to identify waters for Tier 

2 protection. For discussion on why the final rule requirement refers to “public involvement” rather than 

“public participation,” see preamble to the final rule. EPA explains its rationale for requiring “public 

involvement” elsewhere in this section.

EPA considered and agrees with comments supporting clarification regarding identification of high 

quality waters and public involvement. The final rule emphasizes the importance of public transparency 

in identifying waters for high quality water protection. EPA encourages states and authorized tribes to 

consider providing processes by which public citizens and stakeholders can seek Tier 3 (or Tier 2.5, if 

that exists in the jurisdiction) protection for water bodies.

EPA considered comments describing the process a specific state’s antidegradation implementation 

procedures went through in order to be adopted. Some commenters describe the process and effort as 

highly contentious and time consuming. Based on these and other comments, EPA determined that a 

requirement to adopt antidegradation implementation methods is unnecessary partly because their 

adoption may be a burden on some states. Please see response essay 7.f.i for more information on why 

EPA did not finalize a requirement to adopt implementation methods.

EPA agrees with the concern expressed by some commenters that the proposed rule did not require 

states and authorized tribes to engage the public on decisions when implementing a water body-bywater body approach. Consequently, the public would not know the factors a state or authorized tribe 

considered in deciding that the water body did not merit Tier 2 protection, which would limit the 

public’s ability to provide constructive input during the permit’s public notice and comment period. One 

concern is that it has been possible for a state or authorized tribe to structure its water body-by-water 

body approach in a way that eliminates avenues for public involvement on the state’s decisions about 

protecting high water quality. An example would be if the state or authorized tribe makes the decision 

to exclude a water body from Tier 2 protection on a water body basis without public involvement, 

because the decision is made outside of the context of a WQS revision or a permitting action that would 

require public notice and comment. A state or authorized tribe might subsequently allow issuance of a 

National Pollutant Discharge Elimination System (NPDES) permit for an activity that would allow 

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lowering of water quality in that water body without a Tier 2 review. Because the decision not to 

provide Tier 2 protection to that water body was made prior to the permit application, during the 

permit’s public notice and comment period, the public would not have an opportunity to understand the 

basis for the state’s or authorized tribe’s decision that the water did not merit Tier 2 protection. The 

public also would not have an official avenue through which to provide input to the state or authorized 

tribe on factors being considered, or register disagreement with the state’s or authorized tribe’s 

proposed approach. The final requirement at section 131.12(a)(2)(i) requires public involvement in these 

situations, which will increase transparency and accountability on states’ and authorized tribes’ water 

quality management decisions. 

Some comments requested that EPA require public participation standards be applied to the process of 

designation of high quality waters as well as to any determination to remove high quality waters from 

Tier 2 protection. EPA agrees that states’ and authorized tribes’ decisions on whether to provide Tier 2 

protection to (or remove Tier 2 protection from) a water body should be subject to public involvement. 

A key part of a state’s or authorized tribe’s antidegradation process is making decisions on how to 

manage high quality waters, which are a shared public resource. Therefore, any such decisions should 

not and—pursuant to this final rule—must not be made without opportunity for input from the public.

EPA found that public involvement is critical for increasing accountability and transparency in 

antidegradation implementation. Thus, the final rule includes a component specifically requiring public 

involvement for cases in which states and authorized tribes make decisions about Tier 2 protection on a 

water body-by-water body basis. The final rule requirement is consistent with the CWA and the WQS 

regulation’s emphasis (which was described in the proposal preamble) on the public’s role in water 

quality protection. The new requirement adds a layer of public transparency and accountability to the 

ways in which states or authorized tribes make those decisions. This will be particularly valuable when 

using a water body-by-water body approach because such decisions are made looking holistically at the 

water body rather than at any specific chemical, biological, or physical parameter, and because certain 

applications of a water body-by-water body approach can exclude waters from the protections in 

section 131.12(a)(2), even though the water body may have assimilative capacity for some parameters. 

Therefore, it is important that such decisions receive as much public input as possible to ensure the right 

factors are considered. For more discussion on EPA’s rationale for requiring public involvement, see the 

preamble to the final rule. 

Comments expressed the view that “antidegradation reviews must be performed under all three tiers of 

antidegradation, with the reviews documented and subjected to public review and comment.” This 

comment is outside the scope of this regulatory revision. EPA agrees that states and authorized tribes 

must provide all tiers of antidegradation protection where the tiers are applicable. However, this may or 

may not be called “antidegradation review,” depending on what the protection consists of and how the 

state or tribe implements antidegradation. EPA would anticipate that antidegradation reviews are 

typically documented by the permitting authority in the implementing program, for example in an 

NPDES permit factsheet. However, documentation of reviews is not within the purview of the 131 

regulation.

C. Definitions and Wording Clarifications

Comments regarding specific states’ definitions of “short term” degradation are outside the scope of 

this rule. EPA did not propose or finalize requirements that would address these definitions.

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Comments suggested that high quality waters should not be based solely on whether or not an instream parameter exists at a level that is better than applicable criteria, and that a higher threshold 

should be set for high quality waters in order to be practicable for the state or tribe. Comments 

expressed that if this definition is maintained it forces states to do a parameter-by-parameter 

evaluation, which limits the flexibility for states to make their own assessments as to what constitutes a 

high quality water, and would be difficult to implement given the lack of in-stream data for some 

parameters. EPA points out that states and authorized tribes can define for themselves exactly how 

“high quality waters” will be determined, including the data requirements, provided it is consistent with 

the federal rule. The federal rule does not prescribe how states will use data and information to 

determine whether a water is of high quality. In addition, today’s rule allows states to use a water bodyby-water body approach, which allows for much flexibility and does not require a parameter-byparameter evaluation of the water quality.

Comments stated that EPA’s proposed rule “fail[ed] to allow states to promulgate a definition for 

“lowering of water quality” as the term is used as a Tier 2 trigger” and urged EPA to promulgate a 

definition for the final rule. EPA acknowledges the comments’ point that the concept of what, and how 

much, exactly constitutes a “lowering” of high water quality affects what would trigger a Tier 2 review. 

These comments are outside the scope of this rulemaking because EPA did not propose (and did not 

finalize) a definition of “lowering of water quality.” The preamble to the final rule addresses questions 

about “de minimis” considerations.

Commenters suggested that EPA use different wording to prevent confusion around some topics, for 

example, not to say “Tier 2 high quality waters” because the implication is that some waters can be 

called “Tier 1 waters,” which is misleading since Tier 1 applies to all waters. EPA agrees that Tier 1 

applies to all waters of the U.S., and the final preamble thus refers to “high quality waters” and “Tier 2 

review” or “Tier 2 protection” separately. Likewise, EPA agrees that the term “antidegradation reviews” 

can create ambiguity, so the final preamble refers to “Tier 2 reviews.” Commenters also ask for 

clarification on EPA’s statement in the proposal preamble that “antidegradation reviews” are triggered 

by “revisions to effluent limitations based on a TMDL, wasteload allocation, or water quality standard, 

but they are not required for revisions to a TMDL, wasteload allocation, or water quality standard.” EPA 

clarifies here that “antidegradation reviews” in that context meant all applicable aspects of 

antidegradation protection including Tier 1 (though the commenters point out correctly that Tier 1

protection is not commonly considered to be a “review” per se.) The point of the statement in the 

proposal preamble was not to distinguish between Tier 2 and Tier 1 protection. Rather, it was to explain 

that antidegradation protection (all aspects) actually occurs in the context of activities that would affect 

water quality (e.g., changes to an effluent limit in a permit), and not in the context of the planning 

aspects of CWA programs (e.g., antidegradation protection does not actually occur in a TMDL itself.)

See Native Village of Point Hope v. U.S. Envtl. Prot. Agency, No. 3:11-cv-00200-TMB, slip op. at 24-25 

(D. Alaska Sept. 14, 2012).

D. Tier 2 Waters and Tier 2 Review

Some commenters stated that EPA’s proposed Tier 2 review methodology would create a huge burden 

on states and permittees seeking to obtain authorization for new projects. EPA recognizes that many 

states and authorized tribes will have an increased administrative burden to make changes to their 

regulations for consistency with the final rule. However, some states may face no additional burden. 

Some commenters contend that no permittee would be allowed to increase any pollutants to a stream 

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unless they demonstrated they were applying the most stringent wastewater technology that could be 

paid for by the company and that no other project options were determined to be available that would 

decrease pollutant loading, including a reduced project scope or no project at all. EPA disagrees with this

assessment. The final requirement for alternatives analysis, like the proposed requirement addressed by 

the comments, allows for considerable state and authorized tribal discretion as to choosing which 

alternative to implement. They are not required to implement any alternative that is not “practicable,” 

nor are they required to implement the “least degrading” practicable alternative. For more information, 

see response essay 7.b.

EPA acknowledges that comments requested that EPA consider revising the antidegradation Tier 2 

provision in which a state or tribe can allow lowering of water quality if necessary to accommodate 

important economic or social development in the area in which the waters are located. EPA did not 

propose any changes to that aspect of 131.12, so this comment is outside the scope of this rulemaking.

Comments requested that EPA clarify in revision of regulatory language or in preamble, whether “in the 

area” is intended to be local, to the exclusion or regional or statewide, or whether it does not exclude 

broader interests, and whether “development” does or does not include environmental protection. EPA 

did not address these questions in regulatory language or in preamble, as they relate to the 

economic/social development aspect of 131.12 which EPA neither proposed nor finalized changes to, 

and are therefore outside the scope of the regulatory revision. States and authorized tribes have 

considerable flexibility regarding how to consider social and economic development in the context of 

decisions about allowing degradation of high water quality. EPA guidance is available at: 

http://water.epa.gov/scitech/swguidance/standards/economics/. 

Several commenters expressed disagreement with the language in 131.12(a)(2) related to “cost effective 

and reasonable best management practices for nonpoint source control.” Commenters incorrectly 

identified the phrase as a proposed amendment or new requirement, but the phrase was already 

included in the previous regulation before this final rule. These comments are beyond the scope of this 

rulemaking, because EPA neither proposed nor finalized changes to this phase.

Comments expressed the view that where WQS are being met on high quality waters (Tiers 2 and 3), 

“minor degradation should have little or no impact on the uses.” The commenter does not define 

“minor degradation.” Tier 2 and Tier 3 provide protection for water quality above and beyond the levels 

needed to simply protect the designated uses. Hence, “minor degradation” of high water quality in high 

quality waters may not impair the designated uses, but it does degrade the water quality. Therefore, 

section 131.12 may apply even when there is “minor degradation.” Note that states and authorized 

tribes can use de minimis exclusions, as long as they use them in a manner consistent with the CWA and 

section 131.12 (see the Preamble to the final rule for more discussion).

E. Tier 2 Relationship to 303(d) Listing

Comments stated that the proposed requirement for identification of high quality waters is problematic 

in that it could require states to conduct “antidegradation reviews” for impaired waters (waters listed

on 303(d) lists), which would be inconsistent with state anti-degradation policies EPA agrees that it is 

possible for a water to be considered ‘high quality’ (for purposes of Tier 2 of antidegradation) and 

‘impaired’ (by the 303(d) listing program) at the same time. For example, a water might be of high 

quality with respect to some chemical, physical, and biological parameters but impaired with respect to 

others. Tier 2 can provide protection for the high water quality that exists in the water body 

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(e.g., assimilative capacity for some parameters), despite having impairments with respect to some 

parameters. Whether or not pre-existing state and tribal antidegradation policies are consistent with the 

new federal regulation, publication of the final rule means that states and authorized tribes must ensure 

that their regulations are still consistent with the new rule, or update as needed.

Comments related to under what circumstances and how states and authorized tribes would 303(d) list 

waters based on antidegradation are outside of the scope of this rulemaking. The regulations under 

303(d) require states to consider whether waters are meeting any applicable WQS, including 

antidegradation, in their 303(d) listing process. The WQS regulations do not address listing. EPA’s 2014 

Integrated Reporting guidance spoke to this question. (Memorandum dated September 3, 2013 from 

Denise Keehner to Water Division Directors, entitled “Information Concerning 2014 Clean Water Act 

Sections 303(d), 305(b), and 314 Integrated Reporting and Listing Decisions,” 

http://water.epa.gov/lawsregs/lawsguidance/cwa/tmdl/2014-memo.cfm#memo.)

Some commenters did not support the option of utilizing the Integrated Report as a method of 

identifying Tier 2 water bodies due to concern that 303(d) lists are based on limited data sets and will 

not result in long-term protection for waters that consistently exhibit higher water quality. EPA agrees 

that relying solely on the Integrated Report to identify waters for Tier 2 protection can be problematic 

because it can miss important information. For example, if a water is assessed when it is experiencing 

low water quality due to a temporary condition (e.g., drought), a state or tribe looking only at the 

303(d)list might remove the water’s Tier 2 protection, even though the water could have high water 

quality most of the time. This is precisely the kind of situation the final rule is intended to prevent by 

specifying requirements for states and authorized tribes identifying waters for Tier 2 protection on a 

water body-by-water body basis.

F. Activities Subject to Antidegradation Review / Triggers for Tier 2 Review

Comments requested clarification that an antidegradation analysis would be triggered when an increase 

to permitted loadings is proposed. The term “antidegradation analysis” means more than just Tier 2 

review. Tier 1 protection for existing uses applies to all waters, so regardless of what activity is occurring 

on a water body, the state or tribe’s Tier 1 protection should be provided. As for when Tier 2 review is 

‘triggered,’ states and authorized tribes have a variety of approaches, but generally EPA would expect 

that states and authorized tribes initiate Tier 2 review for an activity that would allow more degradation 

than was previously allowed in that water body. One example of this would be a water body with a 

previously-issued NPDES permit to discharge pollutant A into a water body where the water qualitybased effluent limit (WQBEL) for pollutant A is X mg/L. If the state or tribe wishes to re-issue the permit 

with the same WQBEL, the re-issued permit would not allow any more degradation than was previously 

allowed, and Tier 2 review would not be triggered. If the state or tribe wishes to re-issue the permit with 

a WQBEL for pollutant A of X+Y mg/L, it is likely that Tier 2 review will be initiated because the permit 

would allow more degradation than it had previously.

Comments expressed the view that states’ and authorized tribes’ WQS must clearly identify activities 

subject to antidegradation implementation review, giving a list of examples of activities it views should 

be subject to review. These comments are outside the scope of this rulemaking.

Comments expressed the view that no water bodies can be exempted from antidegradation review for 

compliance with antidegradation policy. Citations provided were: Title 40 of the Code of Federal 

Regulations (CFR) section 131.12; 40 CFR section 130.7(b)(3); and Kentucky Waterway Alliance, 

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540 F.3d 466, at 484-85 (6th Cir. 2008). The comment does not explain the relevance of the citations. 

EPA agrees in principle that no water bodies can be exempted entirely from antidegradation protection.

Section 131.12 applies to all waters, although some states do apply de minimis degradation. The he 

three references cited by commenters concerned categorical exemptions for types of activities from 

antidegradation review, not exemptions for specific water bodies.

G. Tier 2 Protection for All Parameters When a Water Body Is Classified as 

Tier 2 under the Water Body Approach

EPA considered comments responding to EPA’s request for comments in the proposal preamble 

regarding whether to specify how a state or tribe determines for which parameters Tier 2 review must 

be conducted depending on the approach used to identify high quality waters. The EPA had requested 

comment on whether, once a high quality water is identified, the Tier 2 review process for that water 

body should differ depending on the approach used to identify it as high quality. The preamble 

explained that EPA could specify that for the water body-by-water body approach, Tier 2 reviews must 

be conducted for all parameters for which the water quality has been identified as better than the 

applicable criteria developed to support the CWA 101(a)(2) uses. Alternatively, the EPA could specify 

that for waters identified as high quality on a water body-by-water body basis, Tier 2 reviews are only 

required for parameters associated with the 101(a)(2) uses currently being supported. Please see 

response essay 7.d.iii for EPA’s response.

H. Antidegradation Review Where Waters Have a “Highest Attainable Use” 

Comments stated that EPA should clarify that antidegradation Tier 2 review is not required in states that 

apply antidegradation review on a waterbody-by-waterbody basis with respect to a “highest attainable 

use” (HAU) and the supporting criteria that are established after a use attainability analysis (UAA( or 

variance. EPA disagrees. EPA recognizes that when a “highest attainable use” is established pursuant to 

a UAA or variance, the use adopted often reflects a use does not support the full use specified in CWA 

101(a)(2). However, a water body that does not exceed levels necessary to support one use specified in 

section 101(a)(2) of the Act may exceed levels necessary to support other uses specified in section 

101(a)(2) of the Act, and may qualify for Tier 2 protection. (Please see section E of this essay and 

response essay 7.d.ii for more discussion of how waters that not supporting all the uses specified in 

CWA 101(a)(2) can still receive Tier 2 protection.) Therefore, it is inappropriate to categorically except 

waters with designated uses that are “highest attainable uses” from Tier 2 review. When determining to 

which waters to provide Tier 2 protection, states and authorized tribes should continue to look at 

whether “the quality of the waters exceeds levels necessary to support the protection and propagation 

of fish, shellfish, and wildlife and recreation in and on the water” (per 131.12(a)(2)). Further, they must 

ensure that waters are not excluded from Tier 2 protection solely because water quality does not 

exceed those levels (per 131.12(a)(2)(i)).

I. Classifying Waters

Comments asked whether the new rule would require states and authorized tribes to classify their 

waters in terms of quality for purposes of antidegradation. The final rule does not require this. States 

and authorized tribes may identify high quality water for high quality water protection on a parameterby-parameter basis. Alternately, they may identify waters for specific tiers of antidegradation protection 

on a water body-by-water body basis. A water body-by-water body basis does not categorize waters in 

categories of ‘quality’ (e.g., a category for ‘low quality waters’ and a category for ‘high quality waters’), 

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but categorizes waters into categories of ‘protection.’ For example, some waters would be categorized 

as receiving Tier 1 protection only, while other waters would receive Tier 1 and Tier 2 protection, and 

others would receive Tier 1 and Tier 3 protection.

J. Tiers of Antidegradation Other than Tier 2

Comments expressed that “Lower quality Tier 1 waters” should not be subject to the highly restrictive 

and regimented antidegradation analysis prescribed by the proposed rule. EPA disagrees with the 

comment. The proposed rule did not propose any changes to Tier 1 of antidegradation. Waters receiving 

only Tier 1 protection would not be subject to Tier 2 review. EPA also disagrees with the characterization 

of the proposed revision to the Tier 2 provision as “highly restrictive and regimented.” The proposal 

would have provided and the final rule provides considerable discretion to states and authorized tribes 

in implementation of Tier 2 of antidegradation.

Comments stated that states and authorized tribes must be required, in their implementation methods, 

to define Tier 1 existing uses and specify that protection of both existing and designated uses is 

required. These comments are outside the scope of this rulemaking.

Comments stated that EPA’s focus on Tier 2 is misguided, because the increasing number of impaired 

waters argues for a focus on Tier 1 protection as well, and because Tier 1 is fundamental to WQS. EPA 

agrees in part that Tier 1 is an important aspect of antidegradation protection and fundamental to WQS. 

However, these comments address Tier 1 which is outside the scope of this rulemaking.

Comments stated that if EPA is establishing requirements for antidegradation implementation, the 

requirements should address implementation of all antidegradation requirements and not just Tier 2 

requirements. This is outside of the scope of this rulemaking.

Comments requested that the proposed “high waters identification criteria” must be applied not only to 

Tier 3 waters but also to Tier 2.5 waters. EPA’s proposal did not propose any changes to requirements 

for Tier 3 or propose any requirements for Tier 2.5 (a concept which does not exist in the federal 

regulation.) This comment is outside the scope of this rule.

Comments indicated that what is actually required for states and authorized tribes related to 

antidegradation is unclear because the CWA says little about it, the federal regulations are brief, and 

interpretations of the requirements are scattered among multiple documents (EPA memos and other 

writings, actions on state and authorized tribal standards, and court decisions.) Comments pointed out 

that the proposed rule addressed a few select antidegradation issues but did not address many others, 

for example “Tier 1,” and requested that EPA be as clear as possible about what is required of states and 

authorized tribes, and how much discretion states and authorized tribes have. EPA points out that the 

CWA and federal regulatory requirements and court decisions interpreting those requirements 

articulate what is ultimately ‘required’ of states and authorized tribes, and that any additional writing 

from EPA results can provide guidance to states and authorized tribes but do not provide binding 

requirements. States and authorized tribes have considerable discretion when addressing 

antidegradation implementation at a more detailed level than the CWA and federal regulations address. 

EPA agrees with the comments that more guidance would be useful, and will consider providing 

additional guidance. 

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K. Antidegradation Implementation Methods as One of the Minimum 

Requirements for Water Quality Standards Submission 

Comments requested that EPA amend section 131.6(d) to clarify that antidegradation implementation 

methods (not only antidegradation policies) are among the minimum requirements for a WQS

submission. The final rule does not require submission of implementation methods to EPA, but requires 

that states and authorized tribes shall provide an opportunity for public involvement during the 

development and any subsequent revisions of the implementation methods, and shall make the 

methods available to the public. Therefore, section 131.6(d) remains accurate without revision.

L. The Proposed Requirements Represent Core Provisions of Policy

Commenters stated that “the proposed requirements for implementation methods in 40 CFR sections

131.12(b)(1) and (2) are not truly implementation methods but, rather, represent core provisions 

relating to the policy itself. These provisions, subject to our comments above, should be included under 

antidegradation policy as opposed to implementation. More importantly, the inclusion of these two 

items under implementation methods gives the erroneous impression that these are the only issues that 

must be addressed in implementation methods.” EPA agrees with this comment. EPA has therefore 

revised the structure of the final rule to reflect that the provisions about high quality water 

identification and about analysis of alternatives are indeed core aspects of policy, not just 

implementation. Please see the preamble to the final rule for more explanation.

M. Minimum Elements of Antidegradation Implementation

Comments stated that the proposal preamble’s list of “areas states’ and authorized tribes’ 

implementation methods would need to address, at a minimum, to be consistent with the WQS 

regulation” does not adequately ensure that states will be required to develop methods that are 

consistent with the CWA and 40 CFR Part 131. EPA agrees with this statement; a list of items in a 

preamble is not a binding rule, and therefore does not, in and of itself, “ensure” any action from state 

and authorized tribes. See response essays 7.g.i and 7.g.iii for additional information about the 

minimum elements.

Comments also stated that the list is inconsistent with the CWA and WQS regulation, and that EPA 

should either include a general statement that implementation plans are to be consistent with the CWA 

and 40 CFR Part 131, or should propose in the rulemaking standards for implementation plans that can 

be reviewed and commented on by the public. EPA disagrees that the proposal preamble list of 

minimum elements was inconsistent with the CWA and WQS regulation at 131.12. The list of elements 

was derived from the elements of the previously existing WQS regulation plus the elements that were 

proposed as rule text and are consistent with the CWA and section 131.12. EPA did not include a list of 

minimum elements in the final rule or preamble. The necessary elements are contained in 40 CFR 

131.12. EPA agrees that states’ and authorized tribes’ implementation methods should be subject to 

public involvement, and has included such a requirement in the final rule.

N. Antidegradation in Practice in a State

EPA considered comments supporting EPA’s description of antidegradation as providing a framework for 

maintaining existing uses, for protecting waters that are either attaining or are of a higher quality than 

necessary to support the CWA 101(a)(2) goals, and for protecting state/tribal identified Outstanding

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National Resource Waters (ONRW). Comments provided Oregon as an example to justify their argument 

that EPA’s description, while theoretically correct, is wrong in practice because it can just be a “set of 

words with little or no real world meaning.” Comments described concerns about the state’s 

identification of existing uses, changes to identification of waters subject to Tier 2 review without public 

comment or approval of its commission, and overly broad exclusion of waters with even one impairment 

from Tier 2 protection, and lack of identified waters for ONRW protection. EPA considered these 

examples and anecdotes and thus includes in the final rule a requirement that states and authorized 

tribes must provide an opportunity for public involvement in decisions about which waters to provide 

(or not provide) with Tier 2 protection on a water body-by-water body basis. Additionally, the final rule’s 

provision regarding conditions on the identification of waters for Tier 2 protection is intended to prevent 

overly broad exclusion of waters from Tier 2 protection and to ensure that the public has a chance to 

participate influence those decisions.

Comments asked what EPA’s proposal preamble meant by “[h]igh quality waters provide support for 

aquatic life and recreation and support unique and significant ecologies and species habitat.” They asked 

whether EPA was referring to actual waters, or waters that some states have identified as “high quality 

waters.” EPA was referring to actual waters that have high water quality, whether states identify them 

for Tier 2 protection or not.

Some commenters explained their view that EPA not taking a specific position on exactly what the scope 

of high quality waters is undermines EPA’s points in the proposal preamble, because states and 

authorized tribes can choose to withhold Tier 2 protection from all or nearly all waters because they

deem the impairment of one parameter to result in the lack of protection for all parameters. These 

commenters argue that EPA’s proposed revisions to the identification of high quality waters would allow 

for variability that can result in some states providing the very best of protection while others provide 

no protection whatsoever, and that EPA should instead require states to identify high quality waters on 

a parameter-by-parameter basis. EPA agrees in part, that the parameter-by-parameter method is clearly 

protective and consistent with the CWA because it protects high quality waters for all parameters for 

which the water has high quality. EPA disagrees that the proposal would have allowed for some states to 

provide no protection whatsoever. The final rule provides a balance between additional accountability 

and conditions for states and authorized tribes using a water body-by-water body method and flexibility 

for states and authorized tribes to implement their programs in a practicable manner. Please see 

response essay 7.d.i for additional explanation of why EPA chose to finalize the new regulatory provision 

for identification of waters for Tier 2 protection. 

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Essay 7.m – Antidegradation: EPA’s Legal Authority

A. Clean Water Act Authority for the Proposal in General

The U.S. Environmental Protection Agency (EPA) disagrees that the proposed changes to the 

antidegradation portion of the water quality standards (WQS) regulation were beyond Congress’ intent

and a “reversal” of current law. As stated in the preamble to the final rule, EPA’s WQS regulation has 

included antidegradation provisions since 1983. Today’s regulation does not reverse current law, but 

revises the antidegradation regulation to enhance protection of high quality waters and to promote 

consistency in implementation. EPA also disagrees with comments stating that the Clean Water Act 

(CWA) does not give EPA authority for the proposed changes to the antidegradation portion of the WQS 

regulation, because the Act did not include the term until 1987. Some comments also argue that the 

reference to antidegradation is only in section 303(d), not 303(c), and in section 118 which instructs the 

Agency to public water quality guidance for the Great Lakes Systems. These comments argue that EPA 

does not have the authority for the regulatory changes in today’s final rule. EPA further disagrees that 

the CWA only establishes authority for states and authorized tribes to establish their own WQS but does 

not establish authority for EPA to review those WQS.

EPA discussed its authority for the final regulation in the preamble stating:

“Some commenters questioned the legitimacy of considering antidegradation a part of WQS,” and 

questioned EPA’s statutory authority to promulgate regulations related to antidegradation. Section 

101(a) of the CWA emphasizes the prevention of water pollution and expressly includes the objective 

“to restore and maintain the chemical, physical, and biological integrity of the Nation’s waters” 

(U.S.C. 1251) (emphasis added). The antidegradation requirements that EPA incorporated by regulation 

in 1983 at CFR 131.12 implement the maintenance aspect of CWA section 101(a) and are an essential 

component of the overall WQS program. Although designated uses and criteria are the primary tools 

states and authorized tribes use to achieve the CWA section 101(a)(2) goals, antidegradation 

complements these by providing a framework for maintaining existing uses, for protecting waters that 

are either attaining or are of a higher quality than necessary to support the CWA section 101(a)(2) goals, 

and for protecting state/tribal identified ONRWs. Antidegradation plays a critical role in allowing states 

and authorized tribes to maintain and protect the valuable resource of high quality water by ensuring 

that decisions to allow a lowering of high quality water are made in a transparent, public manner and 

are based on a sound technical record.

In the Water Quality Act of 1987, Congress expressly affirmed the principle of antidegradation that 

section 101 of the Act articulates. In those amendments to the CWA, Congress incorporated a reference 

to antidegradation policies in section 303(d)(4)(B) of the Act (33 U.S.C. 1313(d)(4)(B)): “Standard 

Attained – For waters identified under paragraph (1)(A) where the quality of such waters equals or 

exceeds levels necessary to protect the designated use for such waters or otherwise required by 

applicable WQS, any effluent limitation based on a total maximum daily load or other wasteload 

allocation established under this section, or any water quality standard established under this section, 

or any permitting standard may be revised only if such revision is subject to and consistent with the

antidegradation policy established under this section.” This provision not only confirms that an 

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antidegradation policy is an integral part of the CWA, but it also explains the relationship of the 

antidegradation policy to some other CWA regulatory programs.1

EPA provides some additional discussion in this essay.

EPA’s legal authority to finalize changes to the antidegradation portion of the WQS regulation derives 

from CWA sections 301(c) and 501(a).

Section 303(c)(1) requires each state to review at least once every three years applicable WQS and, as 

appropriate, modify and/or adopt standards. Section 303(c)(2)(A) requires each state to submit any new 

or revised standards to EPA, and requires that such revised or new standard consist of the designated 

uses of the navigable waters involved and the water quality criteria for such waters based upon such 

uses. Section 303(c)(2)(A) also states that such standards shall be such as to protect the public health or 

welfare, enhance the quality of water and serve the purposes of this chapter. Under section 101(a), the 

purposes of the CWA include “to restore and maintain the chemical, physical, and biological integrity of 

the Nation’s waters” (emphasis added). Antidegradation requirements are a means to “restore” and 

“maintain” the integrity of the nation’s waters. Section 501(a) authorizes the Administrator to prescribe 

such regulations as are necessary to carry out her functions under this chapter.

In addition, the long history of the federal antidegradation policy, of which Congress was aware when it 

passed the CWA in 1972, supports EPA’s authority to promulgate the final rule provisions related to 

antidegradation. The basic federal antidegradation policy was established on February 8, 1968, by the 

Secretary of the Interior. When the CWA was enacted in 1972, the WQS of all 50 states had 

antidegradation provisions. By providing in 1972 that existing state WQS would remain in force until 

revised, the CWA ensured that states would continue their antidegradation programs. EPA’s first WQS

regulation, promulgated on November 28, 1975, included a similar antidegradation policy at Title 40 of 

the Code of Federal Regulations (CFR) section 130.17, 40 Fed. Reg. 55,340-41. EPA slightly refined and 

re-promulgated its antidegradation policy as part of the program regulation published at 40 CFR 131.12, 

48 Fed. Reg. 51,400 (Nov. 8, 1983).

Moreover, Congress acknowledged EPA’s authority to promulgate antidegradation regulations in the 

1987 CWA amendments, in which Congress added CWA section 303(d)(4)(B), which states the following:

“STANDARD ATTAINED.— For waters identified under paragraph (1)(A) where the quality of such waters 

equals or exceeds levels necessary to protect the designated use for such waters or otherwise required 

by applicable water quality standards, any effluent limitation based on a total maximum daily load or 

other waste load allocation established under this section, or any water quality standards established 

under this section, or any other permitting standard may be revised only if such revision is subject to 

and consistent with the antidegradation policy established under this section”(emphasis added).

The phrase “this section” refers to CWA section 303, which governs WQS and implementation plans.

 

1 PUD No. 1 of Jefferson County v. Washington Department of Ecology, 511 U.S. 700, 705 (1994) (“A 1987 

amendment to the Clean Water Act makes clear that section 303 also contains an ‘antidegradation policy... ‘”).

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The Supreme Court has acknowledged the longstanding federal antidegradation policy and EPA’s 

authority to publish antidegradation requirements. In PUD No. 1 v. Washington Department of Ecology, 

511 U.S. 700, 704-05, 718-19 (1994), the Supreme Court discussed the long history of the federal 

antidegradation policy, dating back to 1968, pursuant to which all 50 states had adopted WQS with 

antidegradation provisions. It also acknowledged that EPA has, since 1972, consistently required that 

revised state standards incorporate an antidegradation policy.

As some comments pointed out, the only other reference to antidegradation in the CWA is found in 

section 118. In 1991, Congress included in the CWA provisions section 118 which required EPA to 

publish proposed water quality guidance for the Great Lakes System including guidance on minimum 

WQS, antidegradation policies, and implementation procedures (Title 33 of the United States Code 

[U.S.C.] section 1268 (2)(A)). It further required that within two years after publication of the guidance, 

Great Lakes States shall adopt WQS, antidegradation policies, and implementation procedures for 

waters within the Great Lakes System which are consistent with such guidance (33 U.S.C. Section 1268 

(2)(C)). Under that authority, EPA published the Great Lakes guidance (40 CFR Part 132, Appendix E), 

which included an antidegradation policy and implementation methods addressing many aspects of 

implementation including alternatives analysis, and requires Tier 2 protection on a parameter-byparameter basis. While this section of the Act was limited to the Great Lakes system, it indicates 

Congress’ recognition of antidegradation as a fundamental part of WQS that states and authorized 

tribes must address. 

EPA disagrees with comments that EPA’s proposal exceeded its authority because in CWA section 118, 

33 U.S.C. Section 1268, Congress promulgated the Great Lakes National Program, and Congress also 

required those states to adopt standards, policies, and procedures “consistent with” that guidance. Id. 

section 1268(c)(2)(C). It is true that as a result of that statutory authority, EPA issued regulations that 

included an alternatives analysis (40 CFR Part 132, Appendix E). As pointed out by commenters, those 

regulations describe the alternatives analysis, and then direct states to use the information in evaluating 

whether the lowering of water quality is “necessary,” rather than requiring the states to conduct an 

analysis and choose an alternative. Commenters argued that based on a DC Circuit court ruling 

(American Iron & Steel Institute v. EPA, 115 F.3d 979, 988 (D.C. Cir. 1997)), EPA was authorized to issue 

the Great Lakes regulations because the statute explicitly allowed for them in 1268(c)(2)(A) and the 

regulations left the states flexibility rather than immediately imposing requirements for the states. EPA 

disagrees with commenter’s reading of American Iron and Steel Institute v. EPA. The case does not 

support commenters’ proposition that EPA cannot issue regulations that impose immediate 

requirements on states. The commenter asserts that in American Iron and Steel Institute v. EPA, the 

court said that “EPA was authorized to issue [the Great Lakes regulations] because ‘(2) the regulations 

set out a standard but left the states flexibility to create a program that met that standard – that is, the 

regulations did not ‘immediately impose any requirements’ on the states.” The commenter 

mischaracterizes the court’s statement. In American Iron and Steel Institute v. EPA, the court analyzed 

whether EPA could issue a regulation; challengers argued that EPA was not authorized to issue a binding 

regulation given the language of section 118 requiring EPA to publish water quality guidance for the 

Great Lakes in the Federal Register (FR). When discussing the Great Lakes guidance that EPA published, 

the court stated:

It is clear that § 118 gave the agency the authority to proceed as it did. Petitioners protest that the 

agency had no authority to promulgate a binding regulation. We note first that it is not clear that 

the Guidance can properly be characterized as a binding regulation. It certainly restricts state 

flexibility, but it does not immediately impose any requirements. It merely announces the 

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standards by which state submissions will be judged and informs the states of the default rule that 

the agency will apply if a state submits a nonconforming plan. Regardless of how the Guidance is 

characterized, it is clear that Congress gave the agency the authority to issue the Guidance in this 

form. In previous cases we have held that Congress’s use of the term “guidance” does not 

preclude an agency from doing what the agency did here. (“Congress’ use of the term “guidance” 

is not inconsistent with a rule, like this one, that incorporates a binding performance standard but 

leaves the states considerable flexibility in fashioning programs that meet the standard.”). . . . The 

statute in this case commands the agency to “specify numerical limits on pollutants” and provide 

guidance on “minimum water quality standards.” § 118(c)(2)(A). It is unlikely that Congress would 

have directed the agency to set these limits and standards without also intending to allow the 

agency to enforce them against the states. 

115 F.3d at, 988 (emphasis added and citations omitted). 

Thus, the DC Circuit described EPA’s regulations as “not immediately impos[ing] any requirements,” but 

the court upheld the regulations on other grounds. The court held that even though Congress used the 

word “guidance,” EPA had authority to issue the guidance in the form of a regulation. Therefore, 

commenter’s argument that the section 303 authority does not permit EPA to “require more onerous 

requirements” than in section 118 is flawed. Section 118 gave EPA the authority to issue regulations, 

even though that section used the term “guidance.” Section 303 and section 501 give EPA authority to 

issue antidegradation regulations.

Some commenters stated that CWA 303 is focused on state WQS and programs, not programs to be 

developed by EPA, and so it does not authorize EPA to develop new antidegradation standards and 

impose those obligations on states and authorized tribes. EPA disagrees. CWA 303 does focus on state 

and authorized tribal development of WQS, as they have primacy to implement their programs. 

However, section 303 also explains EPA’s oversight over state and authorized tribal WQS to ensure that 

they are consistent with the Act (which would include sections 101 and 303). As explained elsewhere in 

this section, CWA section 501(a) authorizes the Administrator to prescribe such regulations as are 

necessary to carry out her functions under the Act. 

Commenters argued that Congress has not established any standards against which the

“antidegradation procedures and standards” promulgated by EPA could be judged against to ensure 

they are reasonable and consistent with Congressional intent. They also stated that the proposed 

antidegradation provisions go beyond EPA policy that existed in 1987 when the reference to “the 

antidegradation policy established under this section” was added to section 303(d)(4)(B) of the CWA. 

CWA section 501(a) authorizes the Administrator to prescribe such regulations as are necessary to carry 

out her functions under section 303 (and other sections of the CWA). EPA’s view is that the language in 

303(d)(4)(B) “established under this section” does not mean that the antidegradation policies in effect 

as of 1987 were the only antidegradation policies authorized by the CWA. EPA disagrees that the 

proposal or the final rule would usurp state authority without statutory authorization. EPA’s view is that 

the final rule is reasonable and consistent with the CWA intent to restore and maintain the Nation’s 

waters. EPA also disagrees that the reference in 303(d)(4)(B) to antidegradation policies is drafting error. 

The language has been in the CWA since 1987. The Supreme Court in PUD No. 1 v. Washington 

Department of Ecology stated that the 1987 amendment to the CWA “makes clear that § 303 also 

contains an ‘antidegradation policy’” and cites section 303(d)(4)(B).

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EPA disagrees with comments stating that because CWA 303(c) does not specifically mention 

antidegradation as part of WQS (along with designated uses and criteria), EPA is precluded from 

requiring states to adopt antidegradation policies and methods as part of their WQS. EPA has explained

elsewhere in this section the Agency’s authority for requiring antidegradation policies as a fundamental 

component of WQS. Read as a whole, the Act (including sections 101(a), 303(c),303(d), and 501(a)), 

provides EPA with authority to require antidegradation policies which the Supreme Court acknowledged 

in PUD No. 1 v. Washington Department of Ecology. The final rule does not require states and 

authorized tribes to adopt implementation methods into state or authorized tribal regulations. 

EPA disagrees with comments saying that the previously existing EPA regulatory provisions regarding 

antidegradation at section 131.12 and section 131.6 already apply or exceed the maximum extent of 

EPA’s authority over state and authorized tribal antidegradation policies under the CWA. The proposal 

preamble, today’s final rule preamble, and the discussion above have described EPA’s authority to 

promulgate antidegradation regulations under the CWA. The previous regulations and today’s rule are

within EPA’s authority under the CWA. EPA further disagrees that because the CWA does not specify 

elements of antidegradation implementation methods, those elements are properly left to states and 

authorized tribes. Congress authorized EPA to write rules and regulations that explain the critical details 

necessary to implement the CWA. CWA section 501(a) authorizes the EPA Administrator to prescribe 

such regulations as are necessary to carry out her functions under section 303. Regulations are 

necessarily more detailed than statutory language.

EPA disagrees with commenters that EPA’s proposal meant that EPA would first write implementation 

methods for the states and authorized tribes and then review states’ and authorized tribes’ adopted 

methods “to make sure they get them right.” The final rule does not write implementation methods for 

states and authorized tribes. It sets some boundaries on specific aspects of antidegradation policies and 

requires public involvement and availability of implementation methods. EPA already had authority to 

review and act on adopted antidegradation implementation methods, and the final rule does not change 

that authority. 

EPA agrees that the previously existing version of 40 CFR section 131.12 directed the states and 

authorized tribes to adopt a statewide antidegradation policy and “identify the methods for 

implementing such a policy,” both of which must be consistent with paragraphs 131.12(a)(1) through 

(4), which set out the substantive requirements of an antidegradation provision. EPA agrees that this is 

consistent with the CWA. However, EPA disagrees with comments stating that the application and 

implementation of state WQS is addressed in the previously existing provision at 40 CFR section 131.13 

which stated: “States may, at their discretion, include in their State standards, policies generally 

affecting their application and implementation, such as mixing zones, low flows and variances. Such 

policies are subject to EPA review and approval.” Commenters said that this citation means that not only 

are the implementation policies clearly mandated under current EPA regulations, they are also already 

subject to EPA review and approval, while the method of implementation is left to states’ discretion. 

EPA disagrees. 40 CFR section 131.13 does not refer to antidegradation implementation methods or 

policies; it only refers to policies that are discretionary under the WQS regulation, such as mixing zones. 

40 CFR section 131.12 is the provision specific to antidegradation policies and implementation methods, 

which are not discretionary. Further, EPA reviews states’ and authorized tribes’ adopted antidegradation 

implementation methods as WQS under the same 303(c) authority.

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EPA agrees that the CWA does not explicitly define antidegradation implementation methods as WQS 

and does not create veto authority over states’ and authorized tribes’ antidegradation implementation 

methods. CWA 303(c) did, however, create approval/disapproval authority for EPA over states’ and 

authorized tribes’ legally binding WQS. The WQS regulation at 40 CFR section 131.12 required 

antidegradation policies be adopted. This means, they have to be legally binding. Section 131.6 holds 

that antidegradation policies consistent with section 131.12 are minimum requirements of state and 

authorized tribal WQS submissions. As such, even prior to the final rule, states’ and authorized tribes’ 

antidegradation policies were legally binding, and were subject to EPA review and action under 303(c). 

The final rule revision to section 131.5(a)(3) confirms that states’ and authorized tribes’ legally binding 

antidegradation provisions are subject to EPA review and action under 303(c).

EPA disagrees that the proposal purported to create mandatory duties for states and authorized tribes 

for activities that are far beyond EPA’s jurisdiction. Commenters did not provide evidence for this 

assertion.

Commenters stated that methods for implementing WQS are not WQS for the same reasons that 

compliance schedules (CS) to achieve WQS are not WQS but did not provide a rationale for this statement. 

EPA agrees that implementation methods for WQS are not necessarily new or revised WQS over which 

EPA has 303(c) authority, and that National Pollutant Discharge Elimination System (NPDES) permit CS are 

not new or revised WQS over which EPA has 303(c) authority. However, any analysis of an implementation 

method, CS, or other procedure to determine if it is a WQS is case specific. Commenters did not provide 

specific examples, so EPA is unable to express views on specific CS or implementation methods. To identify 

whether a provision or a document is a new or revised WQS over which EPA has 303(c) authority, it is 

useful to consider “What is a New or Revised Water Quality Standard Under CWA 303(c)(3)?” frequently 

asked questions (FAQs) (http://water.epa.gov/scitech/swguidance/standards/cwa303faq.cfm).

EPA disagrees that the proposed analysis of alternatives requirement exceeds EPA’s authority by 

requiring states to analyze a facility’s planned “upstream” operations (i.e., the internal waste stream, 

operations, etc.), examine alternatives, and choose one if practicable. The final rule’s requirement for 

states and authorized tribes to consider an analysis of alternatives in Tier 2 review does not obligate the 

state or authorized tribe to dictate exactly how a facility must operate to achieve the lessening or 

prevention of degradation that the permitting authority (often the state itself) requires after the state’s 

or authorized tribe’s Tier 2 review and determination of whether degradation is “necessary.” EPA is not 

regulating “upstream” operations, as the commenter argues.

The final regulation requires that “[w]hen the analysis of alternatives identifies one or more practicable 

alternatives, the State shall only find that a lowering is necessary if one such alternative is selected for 

implementation.” It does not require implementation of a particular alternative (e.g. the least degrading 

alternative), but requires that an alternative be selected for implementation in order for the state to 

make a finding that a lowering in water quality is necessary. The selected alternative is chosen because 

it represents a level of degradation that is less degrading than what was proposed. The key point is that 

the state or authorized tribe chooses to allow that level of degradation. The state or authorized tribe 

uses the analysis of alternatives to determine whether (or how much) degradation is “necessary” before 

they issue an authorization (e.g., an NPDES permit) or condition a 401 certification (if EPA or another 

federal agencies issues the authorization) that could allow degradation. The state or authorized tribe 

would issue its authorization or condition the 401 certification reflecting the levels that would allow only 

what they had determined as the “necessary” degradation per the Tier 2 review, based on the expected 

performance of whichever practicable less- or non-degrading alternative was identified and chosen. This 

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could result in the state or authorized tribe choosing to not allow the activity to degrade water quality at 

all, in which case they could deny issuance of an authorization. Or, it could result in allowing a facility to 

degrade water quality only to a limited degree. The facility itself would need to discharge consistent 

with the required levels, but the specifics of how the facility meets the requirements of the 

authorization would be left to the facility. The alternatives analysis identifies how a specific alternative 

can achieve that level of degradation, but ultimately it is possible that the facility can choose to achieve 

the level of degradation specified by its authorization using a different means. See more information at 

essay 7.k.

Comments point out that the CWA section 101 aspirational goal is in a different section from section 

303(d) where antidegradation is mentioned in the context of states and authorized tribes revising their 

own policies, which is a different section from 303(c) that discusses EPA review and action on WQS. EPA 

agrees that as a factual matter, are separate sections of the statute; however, the Agency disagrees with 

the commenters that EPA does not have authority to promulgate the final rule and is altering the 

statutory arrangement. EPA is finalizing regulations that are consistent with the CWA and are necessary 

to carry out the Administrator’s functions under the CWA; the regulations do not alter the statutory 

arrangement. EPA views the sections of the Act together, and explains its authority based on the Act in 

the preamble to the final rule and in this comment response essay.

EPA disagrees with comments saying that Congress’s authorization of EPA in the CWA to review the 

consistency of state WQS with the CWA does not authorize EPA to review the consistency of such WQS 

in light of EPA’s interpretation of other agencies’ policies. Comments said this would leave regulated 

entities in a delicate position: they would be unable to rely on state and authorized tribal interpretations 

of their own WQS or antidegradation policies, or the methods established under those policies, because 

EPA might disagree with those interpretations. First, in the final rule, EPA is not requiring states adopt 

antidegradation implementation methods into rule and therefore not all implementation methods are 

subject to EPA review under the final regulations. If a state has non-binding implementation methods, 

EPA will not review those methods as WQS subject to EPA’s approval or disapproval pursuant to section 

303(c). The rule at section 131.12(b) requires states’ and authorized tribes’ antidegradation 

implementation methods (whether or not those methods are adopted into rule) to be consistent with 

their antidegradation policies and with section 131.12(a). Pursuant to the Agency’s CWA authority to 

review and approve or disapprove state and authorized tribal WQS, EPA fully explores the meaning of 

adopted state or authorized WQS before taking action. In cases where the WQS are ambiguous or 

provide little detail, EPA relies on supporting documentation (including the state’s or authorized tribe’s 

antidegradation implementation methods) that further explains the meaning of the standards so that 

EPA can assure that its action will correctly identify whether the WQS are consistent with the CWA and 

the WQS regulation. Comments argued that if a regulated entity relied upon implementation methods 

selected by an authorized tribe or a state and that method was overturned based on the state’s or

authorized tribe’s policy by EPA, the regulated entity would need to obtain EPA’s own interpretation of 

possible future implementation methods to assess its likely future obligations under the state or tribal 

program (i.e., after the state or tribe proposed alternative methods to satisfy EPA’s own interpretation).

It is unclear what commenters meant by “possible future implementation methods to assess its likely 

future obligations under the state or tribal program.” However, EPA’s response to this hypothetical 

scenario is that in any case where EPA disapproves a state or authorized WQS, the regulated entity will 

be subject to whatever WQS have been approved and are thus effective for CWA purposes. 40 CFR 

131.21 outlines the process by which disapprovals are resolved. However, if EPA finds that a non-binding 

implementation method is inconsistent with section 131.12 or the state’s antidegradation policy, EPA’s 

practice is to notify the state and encourage the state to revise the methods to be consistent with 

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section 131.12 and the antidegradation policy. Maintaining consistency between section 131.12, the 

antidegradation policy, and implementation methods helps provide certainty to the regulated 

community. To the extent that any antidegradation implementation methods undermine the applicable 

CWA antidegradation policy, EPA would have a basis to object to authorizations for regulated activities 

(e.g., an NPDES permit) that are not consistent with the applicable antidegradation WQS or make an 

Administrator’s Determination.

For responses to comments regarding technology-based effluent limits and requirements, please see 

response essay 7.e.ii.

B. EPA’s Authority to Review States’ and Authorized Tribes’ Antidegradation 

Programs

Commenters said that EPA does not have statutory authority to require adoption of antidegradation 

implementation methods. The final rule does not require adoption of antidegradation implementation 

methods.

Commenters objected to the proposal preamble’s characterization of adding language to section 

131.5(a) as “‘describing’ EPA’s authority to review and approve or disapprove” antidegradation policies, 

because they said the action is not a clarification of an existing authority, but rather a codification of a 

new broader regulatory authority without statutory authority, in a manner that would undermine the 

primary role of states and authorized tribes. EPA disagrees. The Agency describes above its authority to 

prescribe antidegradation regulations and to review antidegradation policies under section 303. 

Furthermore, the already existing section 131.12 required states and authorized tribes to “develop and 

adopt a statewide antidegradation policy”. This means, they have to be legally binding. The already 

existing section 131.6 held that antidegradation policies consistent with section 131.12 are minimum 

requirements of state and authorized tribal WQS submissions. As such, even prior to the final rule, 

states’ and authorized tribes’ antidegradation policies were legally binding, and were subject to EPA 

review and action under 303(c). The final rule revision to section 131.5(a)(3) does not add a new 

authority but makes explicit within that subjection that states’ and authorized tribes’ legally binding 

antidegradation provisions are subject to EPA review and action under 303(c).

Commenters said that EPA had incorrectly characterized the changes as clarification of existing 

requirements. EPA agrees that the final rule imposes new obligations, although EPA points out that 

many of the changes represent codification of existing policy that had previously existed as guidance. 

EPA appropriately requested comment on all of the proposed changes, and described its statutory 

authority in the preamble to the proposal. The title of rule does not substantively alter its content.

C. EPA’s Authority for Antidegradation Implementation Methods

EPA disagrees that there is no authority under the CWA to consider states’ and authorized tribes’ 

implementation methods as WQS on which EPA has 303(c) authority to act. Antidegradation 

implementation methods for WQS are not necessarily new or revised WQS over which EPA has 303(c) 

authority, however, if they are adopted as legally binding, EPA would have 303(c) authority. For more 

information, see essay 7.g.ii, and “What is a New or Revised Water Quality Standard Under CWA 

303(c)(3)?” FAQ (http://water.epa.gov/scitech/swguidance/standards/cwa303faq.cfm).

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Some comments stated that since the CWA does not specify or address antidegradation implementation 

methods, the regulation should not dictate requirements for implementation methods and 

implementation should remain a state and authorized tribal responsibility. EPA disagrees. The Agency

has authority under section 501(a) to prescribe regulations to carry out the functions under the CWA

through regulation; thus, the antidegradation regulation requires identification of implementation 

methods that are consistent with the state antidegradation policy and section 131.12(a). The final rule 

does not dictate requirements for the content of implementation methods beyond that they must be 

developed, consistent with the state or authorized tribe’s policy, publicly available, and subject to public 

involvement upon development and revision. The final rule requirements for identification of waters for 

Tier 2 protection and for analysis of alternatives are included in the section on antidegradation policy, 

not implementation methods. For additional information, see essay 7.g.ii.

Some comments asserted that the proposal muddied the discretionary nature of antidegradation 

implementation methods by prescribing their contents. EPA agrees with comments emphasizing the 

importance of being able to include locally-specific considerations in states’ and authorized tribes’ 

implementation methods. To the extent that commenters imply that every aspect of antidegradation 

implementation methods was discretionary prior to today’s rule, EPA disagrees. States and authorized 

tribes must identify implementation methods (a requirement that existed prior to today’s rule) and the 

methods must be available to the public (a new requirement of today’s rule). States and authorized 

tribes have discretion as far as the content of implementation methods as long as they are consistent 

with the state’s antidegradation policy. The final rule continues to allow states and authorized tribes the 

discretion to adopt methods into rule or have them in guidance. The final rule structure is different from 

the proposal, so that the requirements related to identification of high quality waters and analysis of 

alternatives are in the section on antidegradation policies, not the section on antidegradation 

implementation methods. This clarifies that while states and authorized tribes continue to have 

discretion on whether to adopt their methods, their legally binding policies must at a minimum be 

consistent with the new requirements regarding analysis of alternatives and identification of waters for 

Tier 2 protection. Further, while the proposal preamble discussed what EPA viewed as ‘minimum 

elements’ for antidegradation implementation methods to be consistent with 40 CFR 131.12, there is no 

regulatory requirement in the final rule for ‘minimum elements.’ For a state or authorized tribal 

antidegradation program to be consistent with the federal rule, their policy and methods must be 

consistent with 40 CFR 131.12.

Some commenters requested that EPA clarify what antidegradation implementation methods would 

need to include to be consistent with the federal antidegradation regulation. The preamble to the final 

rule discusses EPA’s interpretation of the requirements of the final rule. EPA views the content of 

antidegradation implementation methods as an area in which states and authorized tribes have 

considerable discretion, as long as they are consistent with the federal regulation. EPA will consider 

providing additional guidance, such as examples of provisions of implementation methods that are 

consistent with the federal regulation, in the future.

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D. Concerns beyond EPA’s Legal Authority

Some comments disagreed that EPA’s statement that the nation’s waters face increasing stress from 

anthropogenic influences serves as a basis to revise the antidegradation portion of the WQS 

regulation. Comments stated that since EPA has publicized the success of the CWA (e.g., 

http://water.epa.gov/polwaste/wastewater/treatment/wquality_index.cfm), the need for revisions to 

the regulation on antidegradation is questionable. EPA disagrees. EPA agrees that there have been many 

improvements in water quality at least partially due to the CWA and implementing regulations. For 

example, the document provided by commenters specifically focused on improvements in water quality 

in discharges from Publicly Owned Treatment Works (POTWs) based on EPA grants from 1970 to 1995, 

when many facilities added secondary treatment or greater. However, the scientific basis for the rule is 

evident. Subsequent to large initial improvements following the CWA, water quality problems remain, 

and some are getting worse. For example, the CWA did not place requirements on nonpoint source

(NPS) pollution, and nutrient pollution (which is often largely from NPS) presents a major challenge.

(For more information on data and information about nutrient pollution, please see 

http://www2.epa.gov/nutrientpollution.)

EPA disagrees with comments arguing that the proposal would not provide real environmental benefit. 

See the preamble to the final rule for discussion of environmental benefits of protecting high water 

quality.

Commenters argued that states and authorized tribes have made progress and their current 

antidegradation policies are not ineffective. Comments suggested that EPA should not create new 

requirements that would impact functional, successful programs. EPA agrees that some states and 

authorized tribes have made progress, but progress is not universal, and lists of impaired waters 

continue to grow. EPA disagrees that a “one size fits all” proposal belies current progress and the need 

for states and authorized tribes to be creative and flexible in establishing implementation methods. The 

final rule does not require adoption of implementation methods, and provides considerable discretion in 

how issues are addressed in those methods. Comments stated that states and authorized tribes should 

be able to “test drive” procedures and policies prior to EPA regulating, but did not provide justification 

for this. As EPA described in the proposal preamble, EPA received substantial feedback from 

stakeholders that existing CWA antidegradation regulatory provisions and related guidance have not 

been fully successful in ensuring consistent and effective implementation of Tier 2 high quality water 

protections. States have recognized the limits of national guidance in the area of CWA implementation 

as well. EPA’s view is that states and authorized tribes have already had over 30 years to develop their 

policies and methods, and regulatory changes are needed to protect water quality.

For responses to comments on the proposed rule containing “guidance” (e.g., using the words ‘could,’ 

‘should,’ and ‘may’), See essay 3.a. The final rule language contains words that indicate requirements 

(e.g., ‘shall’) rather than words indicating guidance. The final rule language is what is required of states 

and authorized tribes. Language in the preamble to the final rule provides additional guidance and 

interpretation.

Comments questioned use of the word ‘ensure’ in the proposal. As explained in the preamble to the 

final rule provision on antidegradation does not contain the word ‘ensure,’ but instead retains the word 

‘assure.’ See response essay 10.a.

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Comments stated that nothing permits EPA to dictate the manner in which antidegradation policies will 

be implemented, and had concerns about EPA usurping states’ and authorized tribes’ authority to 

develop their own implementation methods for regionally specific needs and adding more bureaucracy 

to the process. The final rule does not dictate the contents of states’ implementation methods, nor does 

it require they be adopted and submitted to EPA for 303(c) action.

EPA agrees that federalism principles inherent in the CWA give discretion to states and authorized tribes 

to manage their own antidegradation programs, however, EPA does have oversight to a certain extent 

via CWA 303(c). As for ‘vagueness,’ EPA’s view is that the final rule and preamble provide enough 

structure that they will not result in confusion and error, and will consider providing additional guidance 

in the future.

Some comments objected to the proposed changes in antidegradation because the changes would add 

administrative and technical complexity, bureaucracy, and cost to an already time-consuming process. 

EPA recognizes that many states and authorized tribes will have to make changes to their regulations to 

be consistent with the final rule. Undergoing these revisions will increase states’ and authorized tribes’ 

administrative burden. However, some states and authorized tribes may face no additional burden Since 

the final rule provides boundaries on Tier 2 analysis of alternatives and the identification of waters for 

Tier 2 review using a water body-by-water body approach, EPA recognizes that some states and 

authorized tribes will face increased amounts of process and cost to implement programs consistent 

with these requirements. These requirements provide needed boundaries to antidegradation programs, 

but still allow considerable discretion to states and authorized tribes. For example, they may still use de 

minimis exclusions from Tier 2 review to help manage their resources. Further, not all of them will face 

increased process and cost, since some already have antidegradation policies that are consistent with 

the requirements. See the economic analysis (EA) for more information.

Comments objected to the proposed changes to the antidegradation provisions because EPA oversight 

over state and authorized tribal implementation methods would prevent states and authorized tribes 

from applying their antidegradation implementation methods until EPA approves them.

EPA disagrees with comments that the rule has federalism implications, including issues relating to 

Executive Order 13132. See the preamble to the final rule for EPA’s discussion on Executive Order 

13132. The CWA (including the sections of the CWA pertaining to WQS) are based on a principle of 

cooperative federalism. The final rule provisions, including the changes made to the rule since proposal, 

are consistent with the principle of cooperative federalism and are consistent with the CWA. For 

instance, in the final rule, section 131.12(a)(2)(ii) requires a structured analysis of alternatives, which will 

increase transparency and consistency in states’ and authorized tribes’ decisions about high water 

quality. The new requirement makes the analysis of alternatives an integral part of a state’s or 

authorized tribe’s finding that degradation of high quality water is “necessary.” Such an analysis 

provides states and authorized tribes with a basis to make informed and reasoned decisions, assuring 

that degradation only occurs where truly necessary. States and authorized tribes still have discretion to 

decide the order in which they satisfy these requirements and states and authorized tribes themselves 

do not need to conduct the analysis or select the alternative. EPA chose not to require identification of 

the least degrading practicable alternative for implementation to allow states and authorized tribes the 

flexibility to balance multiple considerations.

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EPA disagrees with comments stating that that the proposal expands antidegradation reviews to include 

impaired waters and an alternatives analysis, thus greatly expanding federal control over land and water 

use choices that have been under the purview of states and authorized tribes. The final rule, similar to 

the proposal, does explicitly require analysis of alternatives for Tier 2 reviews, and outlines expectations 

for identifying waters for Tier 2 protection on a water body-by-water body basis. However, it does not 

require Tier 2 reviews for impaired waters; states and authorized tribes still have the authority to decide 

for themselves which waters will receive Tier 2 review. Also, the requirement for analysis of alternatives 

does not mean that the federal government will make decisions about the alternatives. States and 

authorized tribes still have the authority to make decisions informed by analyses of alternatives. Today’s 

rule strengthens the evaluation used to identify and manage high quality waters and increases the 

opportunities for the public and stakeholders to be involved in the decision-making process.

EPA disagrees that the proposed revisions would undermine state and authorized tribal decisionmaking. The final rule provides some boundaries on state and authorized tribal antidegradation policies 

regarding identification of waters for Tier 2 protection and analysis of alternatives in Tier 2 review, but 

does not take away the authority of states and authorized tribes to conduct Tier 2 reviews and make 

decisions about authorizing degradation. EPA agrees that the states and authorized tribes, not EPA have 

the primary responsibility for making decisions about whether to allow degradation of high quality 

water through a Tier 2 review. The final rule does not change that, and thus does not undermine state 

and authorized tribal decision-making.

EPA disagrees with concerns that the proposed changes to the antidegradation regulation would grant 

EPA a veto authority to override states’ and authorized tribes’ decisions to allow degradation. WQS, 

including antidegradation, are not directly enforceable. They are implemented through other actions 

such as NPDES permits. EPA has never had, and will not have under the final rule, enforcement authority 

over WQS themselves since they are not directly enforceable. However, the CWA expressly gave EPA 

oversight and enforcement authority in several areas where WQS are implemented, such as NPDES 

permits (33 U.S.C. Section 1319). This means for example that if a state or authorized tribe with NDPES 

authority issues an NPDES permit that must derive from and comply with WQS (per 40 CFR Part 122), 

but that permit fails to adequately implement the state’s or authorized tribe’s own antidegradation 

policy (e.g., appropriately conducting Tier 2 review where applicable), EPA has the authority to exercise 

its oversight over that permit. This authority was pre-existing and is not changed by the final rule. EPA 

agrees with comments that EPA must give deference to states’ and authorized tribes’ decisions as long 

as those decisions are consistent with the applicable WQS.

EPA disagrees that including antidegradation implementation methods as elements of WQS needlessly

increases federal intrusion in a role expressly delegated to states by the CWA. The final rule does not 

require states and authorized tribes adopt implementation methods into rule. Some states and 

authorized tribes choose to incorporate implementation methods as legally binding provisions that they 

then submit to EPA for action under CWA 303(c). This is a choice and not a requirement, so there is no

increase in federal intrusion. The final rule does not require states to adopt and submit their 

implementation methods.

Some commenters stated that the preamble to the proposal did not explain the effect of the proposal 

on existing approved implementation policies. EPA clarifies here that in the future, following the 

publication of the final rule, states and authorized tribes will need to ensure that their antidegradation 

policies are consistent with the final rule requirements, and that their implementation methods must 

likewise comport with the final rule requirements. The preamble to the final rule explains what EPA 

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expects as far as the timeline for states and authorized tribes to comply. EPA disagrees that the 

proposed changes would have a chilling effect on future states’ and authorized tribes’ efforts to develop 

improved and innovative policies. Commenters did not provide evidence for this assertion. EPA’s view is 

that the final rule provides ample discretion for states and authorized tribes to innovate and improve.

For information about what constitutes a new or revised WQS over which EPA has CWA 303(c) 

authority, see the “What is a New or Revised Water Quality Standard Under CWA 303(c)(3)?” FAQ. 

(http://water.epa.gov/scitech/swguidance/standards/cwa303faq.cfm) 

E. Water Quality Standards Include Antidegradation

Some commenters argued that EPA should amend the statement of purpose for WQS at section 131.2 

by adding antidegradation to acknowledge that WQS include antidegradation, and by adding a 

statement about protecting existing uses to acknowledge existing uses as the absolute floor of water 

quality. EPA chose not to amend section 131.2 at this time. EPA also chose not to amend the formal 

definition of WQS at section 131.3(i) by adding antidegradation, to read consistent with section 130.7(b) 

which describes WQS as “including...antidegradation requirements.” EPA did not propose or finalize a 

revision to add reference to antidegradation requirements, existing uses or Tier 1 protections, or 

descriptions to further explain the meaning of designated uses, criteria, and antidegradation 

requirements in section 131.2, or amend the formal definition of WQS at section 131.3(i). EPA 

concluded the changes were not necessary because the existing regulatory structure already included 

antidegradation as a core, required component of WQS. Provisions that are already explicit to 

antidegradation already existed in section 131.12 and section 131.6 (which explains that 

antidegradation policies consistent with section 131.12 are minimum requirements of WQS 

submissions). Further, the 303(d) listing regulation at section 130.7(b) corroborates this, stating that: 

“For the purposes of listing waters under Section 130.7(b), the term “water quality standard applicable 

to such waters” and “applicable water quality standards” refer to those water quality standards 

established under Section 303 of the Act, including numeric criteria, narrative criteria, waterbody uses 

and antidegradation requirements.” (That is, the state’s antidegradation requirements as approved by 

EPA under 303(c).) Finally, EPA revised section 131.5(a)(3) to further confirm that states’ and authorized 

tribes’ legally binding antidegradation provisions are subject to EPA review and action under 303(c). See 

further discussion in essay 10.a.

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