CHAPTER 3 

Issue Category: Designated Uses 

Pages 3-33 – 3-110

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 5.a – DU – Gen Supp 

Essay 5.a – Designated Uses: General Support

The U.S. Environmental Protection Agency (EPA) agrees with commenters’ support for the revisions 

pertaining to how states and authorized tribes designate and revise designated uses for individual water 

bodies and the requirement to adopt the highest attainable use (HAU). EPA agrees with commenters 

that the rule’s clarifications related to designated uses, will better help states and authorized tribes 

restore and maintain resilient water quality and robust aquatic ecosystems consistent with Clean Water 

Act (CWA) objectives. EPA agrees that the requirement to adopt the HAU is generally consistent with 

how many states and authorized tribes already implement their water quality standards (WQS) 

programs.

For more information about states’ and authorized tribes’ discretion on how to articulate the HAU, see 

EPA’s response to 5.f.i.

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Chapter 3 – Response Essays 5.b – DU – Gen Opp

Essay 5.b – Designated Uses: General Opposition

The U.S. Environmental Protection Agency (EPA) agrees with the comment that the current regulatory 

regime related to removing and revising designated uses is workable, but disagrees that the final rule 

will make it more difficult or will discourage states, authorized tribes, and stakeholders from pursuing

revisions to designated uses. The purpose of the final rule is to further improve and clarify the process 

by which states and authorized tribes designate and revise uses by more clearly articulating in rule and 

preamble that a use attainability analysis (UAA) is only required in the circumstances specified in section

131.10(j). In addition, the final rule establishes a requirement to adopt the highest attainable use (HAU), 

which makes clear how states and authorized tribes meet Clean Water Act (CWA) requirements. The 

requirement for HAU is linked to the UAA process such that the HAU is the use based on the evaluation 

of factors in section 131.10(g) that preclude attainment of the use and any other information and 

analyses that were used to evaluate attainability. Thus, adopting the HAU is not a subjective decision, 

nor does it require a separate analysis in addition to a UAA. In addition, the final rule clarifies that states 

and authorized tribes are not required to conduct a UAA in specific circumstances outlined in section

131.10(k), further streamlining the regulatory process. For additional discussion on the topic of adopting 

the HAU, please see response essays 5.f. and 5.f.i.

EPA disagrees that the final rule is inconsistent with its March 2006 memorandum issued by Ephraim 

King on “Improving the Effectiveness of the Use Attainability Analysis (UAA) Process” and continues to 

stand behind the principles articulated in the March 2006 memo. Specifically in response to comments 

received, EPA continues to encourage state and tribal partners to work together to make the UAA 

process operate as efficiently as possible, and reiterates that there is nothing wrong with changing 

designated uses after completion of a credible and defensible UAA. Specifically, in the preamble to the 

final rule, EPA says “Designated uses drive state and authorized tribal criteria development and water 

quality management decisions. Therefore, clear and accurate designated uses are essential in 

maintaining the actions necessary to restore and protect water quality and to meet the goals and 

objectives of the CWA.” In fact, EPA specifically targeted the uses provisions at section 131.10 as a 

follow up to the Ephraim King memo because multiple stakeholders provided feedback that more clarity 

would allow states, authorized tribes, and the public to engage in a more streamlined and transparent 

process to revise designated uses.

EPA agrees that many states currently allow for use revisions and use removals; however, EPA disagrees 

that revisions to the federal regulation are therefore unnecessary. In EPA’s experience, states and 

authorized tribes may adequately demonstrate that a particular use is unattainable and remove the use, 

but fail to designate an alternate use or sub-category of a use that is feasible to attain. As EPA explains 

in the preamble to the final rule “...if some less sensitive aquatic organisms are able to survive at the site 

under current or attainable future conditions, the state’s or authorized tribe’s WQS are not continuing 

to serve the goals of the CWA by removing the aquatic life use designation and applicable criteria 

altogether without adopting an alternate CWA section 101(a)(2) use or sub-category of such a use that is 

feasible to attain, and the criteria that protect that use.” EPA views the concept of HAU as being 

fundamental to the water quality standards (WQS) program. Therefore, the final rule revises section

131.10(g) to provide that where states and authorized tribes adopt new or revised WQS based on a 

required UAA, they must adopt the HAU.

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Chapter 3 – Response Essays 5.c – DU – UAA Process

Essay 5.c – Designated Uses: UAA Process

The U.S. Environmental Protection Agency (EPA) disagrees that the requirement that the factors 

identified in section 131.10(g) be used whenever a use attainability analysis (UAA) is required is overly 

stringent. The final rule does not change the longstanding requirement that states and authorized tribes 

must use the factors listed in section 131.10(g) to demonstrate whether a use is unattainable. Rather, 

the final rule provides additional clarity that states and authorized tribes are only required to use the 

factors in section 131.10(g) when conducting a UAA required by section 131.10(j). The final rule further 

clarifies that states and authorized tribes are not required to use the factors in section131.10(g) when a 

UAA is not required, such as when removing or revising a non-101(a)(2) use. 

The final rule does not modify the section 131.10(g) factors for designated uses in any way and, 

therefore, such a comment relating to the specific factors is out of the scope of this rulemaking. EPA has 

developed publicly available documents for states and authorized tribes when evaluating relevant data 

and information to determine whether one of the factors precludes attainment of the designated use.

See “UAAs and Other Tools for Managing Designated Uses”1 (March 2006) and “Interim Economic 

Guidance for Water Quality Standards”2 (March 1995).

EPA disagrees with the comment that many UAAs use minimal data to determine if a use is or is not 

attainable, and therefore would not satisfy EPA’s requirement for highest attainable use (HAU). The HAU 

requirement is linked to the UAA process such that the HAU is the use based on the evaluation of factors 

in section 131.10(g) that preclude attainment of the use and any other information and analyses that 

were used to evaluate attainability.

The final rule does not modify the substantive requirements at sections 131.10(g) and (h)(1) that 

prohibit removal of an existing use. EPA’s intent with the example provided in the proposal (78 FR 

54523) was to clarify that the regulatory prohibition on removing existing uses (sections 131.10(g) and 

(h)(1)) does not apply where removal would result in improving the condition of a water body to be

more like its minimally impacted condition. The purpose of existing uses is to help meet the objectives 

of the Clean Water Act (CWA) to restore and maintain a water’s chemical, physical and biological 

integrity and thus the prohibitions on removing an existing use in sections 131.10(g) and (h)(1) do not 

apply in this limited instance. One commenter stated that if a state removes a warm water fishery 

designated use due to dam removal, then the new cold water fishery would require more stringent 

criteria. Generally speaking EPA agrees with this comment but notes that a state or authorized tribe may 

not always be required to adopt more stringent criteria when restoring a water body to its more 

minimally impacted condition. One example may be a scenario where a state artificially stocks waters 

with cold water fish, such as trout, to maintain a sports fishery. However, some years later, the state 

may choose to restore the water to its minimally impacted condition, which is a warm water aquatic life

use. In this instance the state would not be required to continue artificially maintaining a cold water 

fishery because it is an existing use, at the expense of restoring the water to a warm water aquatic life 

use and thus a less stringent temperature criterion.

 

1

http://water.epa.gov/scitech/swguidance/standards/upload/2007_08_08_standards_uses_uaa_cs-all.pdf 2

http://water.epa.gov/scitech/swguidance/standards/upload/2007_06_18_standards_econworkbook_complete.pdf

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Chapter 3 – Response Essays 5.d – DU – Existing Uses

Essay 5.d – Designated Uses: Existing Uses

The U.S. Environmental Protection Agency’s (EPA’s) regulation at 131.10(h)(1) (established prior to 

todays’ rule) provides that states may not remove a designated use if the use is an existing use unless 

the state adopts a use requiring more stringent criteria. Title 40 of the Code of Federal Regulations (CFR) 

section 131.10(g), (established prior to today’s rule), refers back to the requirement in section 131.10(h) 

by noting that that a state “may remove a designated use which is not an existing use.” 40 CFR 131.10(h) 

applies to all use removals. In its proposal, published September 4th, 2013, EPA did not propose any 

changes to 131.10(h). While EPA’s proposed rule language in section 131.10(g) provided that a state 

may remove a use if it does not “remove protection for an existing use,” EPA did not intend to change 

the existing use requirement that resides in section 131.10(h)(1). Therefore, the final rule language in 

section 131.10(g) does not reflect the proposed rule language and continues to use the same language 

that previously existed related to existing uses. EPA retained this language to avoid any confusion or 

misunderstanding that section 131.10(g) creates a different requirement than section 131.10(h)(1). No 

individuals commented on the specific proposed rule language in 131.10(g) that a state or authorized 

tribe may remove a use if it does not “remove protection for an existing use.” Please see response 

essay 5.g. for detailed discussion of why EPA did not finalize the proposed language.

EPA’s discussion of existing uses in the proposal was restricted in scope to two specific and limited

interpretations regarding existing uses. First, EPA described its interpretation of the language in the 

definition of existing use in 131.3(e) to mean that the uses are “actually attained” when both the use 

and the water quality necessary to support the use have been achieved. EPA explained where data is 

limited, inconclusive or not available to determine either that the use or water quality to support the 

use is achieved, that the state or authorized tribe has the discretion whether or not to make an existing 

use determination. Second, EPA explained that the existing use requirement in 131.10(h)(1) does not 

apply where a state or authorized tribe is removing a use that will result in improving the condition of 

the water body to be more like its minimally impacted condition. EPA solicited comment on these 

interpretations and therefore EPA is responding to comments on these topics raised in the proposed 

rule preamble and response to comments. Therefore, EPA is responding below to the comments 

received on these interpretations only. As discussed below, all remaining comments on existing uses are 

outside the scope of this rulemaking. 

Finally, EPA acknowledges the requests for additional guidance on how states and authorized tribes 

should identify and protect existing uses. EPA will consider providing additional information about 

existing use determinations as it develops further guidance on water quality standards (WQS) after 

publication of this final rule. 

A. Comments regarding EPA’s Interpretation That the Requirement in 

131.10(h)(1) Does Not Apply When a State or Authorized Tribe Is Removing a 

Use That Will Result in Improving the Condition of the Waterbody to Be More 

like Its Minimally Impacted Condition

EPA’s basis for the position that 131.10(h)(1) does not apply when a state or authorized tribe is 

removing a use that will result in improving the condition of the waterbody to be more like its minimally 

impacted condition is rooted in the requirement that WQS must “serve the purposes of this chapter,” 

which include the objective of the Act to “restore and maintain the chemical, physical, and biological 

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Chapter 3 – Response Essays 5.d – DU – Existing Uses

integrity of the nation’s waters.” Referring to the term “integrity” in the statutory goals, the House 

Report stated:

[T]he word “‘integrity” as used...refers to a condition in which the natural structure and function 

of ecosystems [are] maintained. As a concept that refers to a condition in which the natural 

structure and function of the ecosystem is maintained....Although man is a “part of nature” and 

a product of evolution, “natural” is generally defined as that condition in existence before the 

activities of man invoked perturbations which prevented the system from returning to its 

original state of equilibrium. This definition is in no way intended to exclude man as a species 

from the natural order of things, but in this technological age, and in num[sic]erous cases that 

occurred before industrialization, man has exceeded nature’s homeostatic ability to respond to 

change. Any change induced by man which overtaxes the ability of nature to restore conditions 

to “natural” or “original” is an unacceptable perturbation.

H.R. Rep. No. 92-911, 92nd Cong. 2d Sess. 76 (1972). Therefore, EPA’s position regarding the 

applicability of the requirement in 131.10(h) discussed above is consistent with the Clean Water Act 

(CWA) because it allows for the restoration to minimally impacted conditions. 

EPA received a comment that supported EPA’s interpretation but provided the following example “a 

stream’s original Fish & Aquatic Life use was warmwater, but a facility discharged cold effluent resulting 

in a coldwater stream. If the facility changes hands to a different type of industrial process, now 

discharging warm water, it is reverting to its more natural use, which would be allowable under this 

clarification.” EPA notes that the commenter’s example is not on point because EPA’s interpretation is in 

the context of revising a designated use whereas the commenter’s example is put in the context of a 

change in industrial discharge. The commenter’s example also incorrectly implies that the minimally 

impacted condition is always the “original” use. This may not always be the case as the minimally 

impacted condition may not have ever been designated. An appropriate example to demonstrate EPA’s 

interpretation would be if a stream was designated for a coldwater fish and aquatic life use because of a 

long time discharge of cold effluent from a facility that resulted in supporting this designated use. If the 

facility shut down or moved operations, the regulation at section 131.10(h)(1) and section 131.10(g) 

would not prohibit the state or authorized tribe from revising the designated use from a cold water fish 

and aquatic life use to a warm water use if the minimally impacted condition was in fact a warm water 

fish and aquatic life use.

B. Comments regarding EPA’s Interpretation of “Actually Attained” in the 

Definition of Existing Uses 

EPA’s articulation in the preamble to the final rule states that an existing use is known to be “actually 

attained” when there are data to show that the use has actually occurred and the water quality has 

been attained. EPA’s original interpretation of this language in a 1985 Antidegradation Questions and 

Answers document was that “An existing use can be established by demonstrating that fishing, 

swimming, or other uses have actually occurred since November 28, 1975 or that the water quality is 

suitable to allow such uses to occur (unless there are physical problems which prevent the use 

regardless of water quality.)” EPA’s 1994 WQS Handbook, Chapter 4 Antidegradation, repeated this

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Chapter 3 – Response Essays 5.d – DU – Existing Uses

interpretation1

. Additionally, in the 1998 Advance Notice of Proposed Rulemaking (ANPRM), EPA said 

“...an existing use finding can be made either where the use is or has been “actually attained” or where 

the water quality necessary to support the use is in place even if the use, itself, is not currently 

established....” (63 FR 36752, July 7, 1998). Comments cited to an example in a former EPA document 

regarding shellfish harvesting as being clear that “the assessment of ‘existing uses’ should be found in 

the absence of the actual use.” However, EPA initially explained its change in its interpretation from an 

“or” to an “and” in its September 2008 letter from EPA to the State of Oklahoma 

(http://water.epa.gov/scitech/swguidance/standards/upload/Smithee-existing-uses-2008-09-23.pdf) 

which EPA referred to in its proposed rule preamble along with EPA’s current interpretation.

EPA received a comment that said the commenter recommended that “EPA revise the preamble 

description of when an existing use is “known to be attained” to “states have discretion to determine 

whether an existing use has been attained, based on either the actual use or the water quality necessary 

to support the use has been achieved.” EPA agrees that states and authorized should have some 

discretion but disagrees that this discretion should apply all the time. As discussed in the 2008 letter, 

this change in interpretation is based on EPA’s experience in implementing the existing use requirement.

EPA’s definition uses the term “actually attained” where “actually” means a use “actually occurred” and 

“attained” means where the water quality to support the use has been attained. EPA’s 2008 letter 

explained that an approach for determining the existing use on either use or water quality allows states 

and authorized tribes to determine an existing use where it has definitive information only on whether 

the use has occurred or whether the water quality has been attained, some have misinterpreted this 

statement as obligating a state or authorized tribe to ignore one set of information where data is 

available on both the use and the water quality. For example, where data shows definitively that a use 

has not actually occurred but the water quality has been attained, some may interpret EPA’s statements 

in the 1998 ANPRM as meaning that a state must ignore the data regarding the use and determine that 

there is an existing use solely because the water quality has been attained. Section 131.10(h) serves as 

gate keeper provision that determines whether a state can remove designated use. EPA’s current 

interpretation allows states and authorized tribes to require sufficient evidence that both the use and 

the water quality necessary to support the use exist in order to qualify as an existing use for purposes of 

131.10(h)(1). EPA’s current interpretation is intended to ensure that when states and authorized tribes 

are evaluating existing uses to determine whether they would be “removed” by the removal of a 

designated use, that they are using information to accurately characterize the existing use. It is not 

scientifically defensible to arbitrarily ignore available data and EPA has determined that “taking into 

account all the available information results in a more accurate articulation of the existing use.” EPA’s 

2008 letter and today’s final rule address situations where there is limited or inconclusive data such that 

a state or authorized tribe may still be able to determine the existing use based on whether the use has 

occurred or whether the water quality has been attained when that is the only information available. 

Specifically, the preamble to the final rule reiterates the 2008 letter and says “EPA recognizes, however, 

that all the necessary data may not be available to determine whether the use actually occurred or the 

water quality to support the use has been attained. When determining an existing use, EPA provides 

 

1 A commenter referenced this original interpretation by saying “EPA states in its Water Quality Standards 

Handbook (2d ed. March 2012), However, EPA did not have a 2012 edition of the WQS Handbook. The language 

cited by the commenter from Chapter 4.4 was written in 1994 and has not changed since then. In 2012, EPA 

included some links to additional information and resources that EPA developed subsequent to 1994 in the online 

version of the Handbook. None of the text of the chapters changed from the 1994 version in 2012. Please see 

EPA’s website for this disclaimer. EPA will consider updating this language as it develops new guidance after 

publication of the final rule.

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Chapter 3 – Response Essays 5.d – DU – Existing Uses

substantial flexibility to states and authorized tribes to evaluate the strength of the available data and 

information where data may be limited, inconclusive, or insufficient regarding whether the use has 

occurred and the water quality necessary to support the use has been attained. In this instance, states 

and authorized tribes may decide that based on such information, the use is indeed existing.” 

This means that where there is limited or no data on one or both of the factors, a state or authorized 

tribe may conclude there is not enough evidence to identify the designated use as the existing use. In 

such a case, a state or authorized tribe has two options they may pursue. First, the state or authorized 

tribe can use its discretion to determine the existing use (i.e., the “floor”) based on the evidence that is 

available. This interpretation is not meant to restrict or limit a state or authorized tribe’s discretion to 

determine that the designated use is also the existing use based on the strength of the available data, 

even where such data is inconclusive. As a second option where data is limited, inconclusive or 

insufficient, states and authorized tribes may decide to retain a designated use as their desired 

condition and therefore there is no need to determine the existing use at that time. Such an action 

would be consistent with CWA section 510 and EPA’s implementing regulations at 131.4 that recognize 

that a state may develop WQS that are more stringent than CWA requirements. Therefore, EPA 

acknowledges commenters point that its current interpretation differs from EPA’s prior statements but 

as discussed above, EPA provided and maintains a reasonable basis for this changed interpretation. 

EPA received a comment concerned that states do not have extensive data to inform existing use 

decisions and that in the absence of this data and in the absence of a serious and clear EPA policy on 

how to identify existing uses “this key provision is simply ignored in nearly every regulatory action states 

take...” EPA disagrees that there is an absence of serious and clear EPA policy on how to identify existing 

uses. As discussed throughout this essay, EPA as clearly stated its policy for how states and authorized 

tribes are to determine existing uses where there is insufficient or inadequate data in its 2008 letter, and 

the preambles to the proposed and final rule. In addition, EPA will consider providing additional detailed 

guidance in subsequent guidance it will publish after publication of the final rule.

EPA agrees with the comment that determining whether or not a designated use is an existing use must 

involve a careful analysis of data and information beyond the current conditions of a water body since 

an existing use is any use actually attained on or after November 28, 1975. This could include data and 

information about uses that were actually attained on or after that date, but is not currently attained. 

State and authorized tribal decisions on existing uses should be made on a site-specific basis and could 

include (but are not limited to) measures such as speaking to local landowners and local/state/federal 

land management representatives about historical conditions; current and historical land use practices; 

and current and historic flow data.

For the reasons discussed in this section, EPA disagrees with comments that EPA’s current interpretation 

of existing uses is contrary to a plain reading of the definition of existing uses at section 131.3(e) (i.e., 

“existing uses are those uses actually attained in the water body on or after November 28, 1975...”). 

EPA’s regulation at section 131.3(e) uses the phrase “actually attained” and does not utilize “actual use” 

as the sole qualifying criteria for existing use as the comments suggest.

Some comments expressed concern that EPA’s position on existing uses supports the removal of a 

designated use in a situation where the use has actually occurred, but the water quality necessary to 

protect the use has never been attained (and vice versa), and that such a position may be detrimental to 

a state’s or authorized tribe’s ongoing water quality protection and preservation efforts (e.g., a water 

body may have never achieved the water quality necessary to support a primary contact recreation use, 

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Chapter 3 – Response Essays 5.d – DU – Existing Uses

but the use routinely occurs and the state desires to restore the water body so that it attains the 

designated use). Commenters also expressed concern that EPA’s position “eliminates threshold water 

quality protections necessary to attain the CWA’s goal of restoring and maintaining the chemical, 

physical and biological integrity of the Nation’s waters.” The comments also noted that the discussion in 

the letter to the State of Oklahoma is much more nuanced than the preamble suggests. EPA agrees that 

there are nuances that were not fully incorporated into the preamble. EPA cited to the letter to State of 

Oklahoma so that readers may read it for the nuanced discussion. In regard to the specific concern of 

EPA’s position supporting removal of a designated use where the use is not existing and that it removes 

threshold protections, the regulation requires that even if a designated use is not an existing use, the 

state or authorized tribe must provide a justification for removing that designated use. For example, in 

cases where the designated use in question is a primary contact recreation use, then the state or 

authorized tribe must demonstrate that the primary contact recreation use is not feasible to attain 

based on one of six specific factors provided in section 131.10(g) and obtain public input through a 

public hearing on its decision before obtaining EPA approval before the use change is effective for CWA 

purposes. Therefore, if there is insufficient data to affirmatively determine that the water quality was 

never attained since November 28, 1975, as discussed above, the state has discretion to determine that 

the use is still existing based on the information that is available, such as the common use of the water 

for recreation (see section B of the preamble to the final rule for additional discussion).

With regard to comments that interpreted language in EPA’s letter to the State of Oklahoma to mean 

that as long as “the state’s or tribe’s identified existing use is maintained, the state or tribe should be 

free to remove or modify the designated use without any need for a UAA” the EPA notes its statements 

regarding the letter to Oklahoma were intended to explain its interpretation of the definition of existing 

use. The commenter is incorrectly using EPA’s statements in his/her conclusion and leads to an incorrect 

reading of the CWA and the regulation. The regulation sets existing uses up as a “floor” below which 

water quality should not go in order to “maintain” actually attained uses and water quality, consistent 

with the CWA. However, maintaining the existing use alone does not fully meet the objectives of the 

CWA which, in addition to “maintenance,” also includes “Restoration...of chemical, physical, and 

biological integrity of Nation’s waters.” 

EPA agrees with comments that evidence of incidental or opportunistic temporary presence of one or a 

few individuals (e.g., one or a few individual fish) may not necessarily constitute an existing use, but 

disagrees that designation of the use may not be required in this scenario. Where a few individual 

aquatic species are incidentally or temporarily present in a water body, EPA finds it reasonable for a 

state or authorized tribe to conclude that there are not enough data to know that the use actually 

occurred and the water quality to support that use was attained in order to say that a warm water 

aquatic life use is an existing use. However, when designating uses, states and authorized tribes should 

consider a number of factors in addition to the existing use, such as the current use that is attained, as 

well as the use(s) that may be attainable in the future. If several fish are observed utilizing a water body 

on a transient, temporary basis, it may be reasonable to expect similar occurrences in the future, and 

therefore an aquatic life use designation may be attainable and appropriate. States and authorized 

tribes should engage their public in determining the highest attainable use (HAU) for such a water body.

Multiple comments said that many states historically designate uses without regard to attainability and 

reliable records regarding existing uses are often incomplete or unavailable. States and authorized tribes 

need to determine the existing use at the time it is used to implement the regulatory requirements 

(e.g., when considering a revision to a designated use per section 131.10(h)(1)). Existing uses can change 

over time with water quality improvements as it represents the best use actually attained since 

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Chapter 3 – Response Essays 5.d – DU – Existing Uses

November 28, 1975. Identifying such changes to the existing use are critical to the function of 

maintaining water quality consistent with the objectives of the CWA. EPA’s regulation, therefore, does 

not require, nor does EPA encourage, states and authorized tribes to adopt existing uses into WQS as 

doing so would not facilitate identification of the real time improvements to waters that is envisioned by 

the CWA. Because existing uses are determined in real time for use in implementing the section 131.10 

and section 131.12 regulations, EPA disagrees with commenters that EPA should encourage states and 

authorized tribes to “revisit” whether those existing use determinations are realistic or attainable and, if 

not, correct them. All existing uses are “revisited” anew when they are determined but because the 

regulations do not require existing uses to be adopted, there is nothing to “correct”. The definition of 

existing uses at section 131.3(e) reflects this position because it includes the phrase “whether or not 

they are included in the water quality standards.” To the extent that states or authorized tribes have 

chosen to formally adopt existing uses into their WQS regulations, states and authorized tribes must still 

determine the existing use each time they apply the relevant provisions from 131.10 or 131.12. 

EPA disagrees with the comment that the attainability of existing uses should be evaluated. The purpose 

of existing uses is to articulate the uses that have already been “actually attained” so that future water 

quality and designated uses are managed to maintain and protect these existing uses. EPA’s 1998 

ANPRM stated “As discussed in the background section above, the regulation defines ‘‘existing uses’’ as 

‘‘those uses actually attained in the water body on or after November 28, 1975, whether or not they are 

included in the water quality standards.’’ (40 CFR 131.3(e)). As a result, the focus of existing uses, is on 

the past or present condition of the water body. Furthermore, by establishing requirements prohibiting 

the removal of existing uses and ensuring those uses will be appropriately recognized in State and Tribal 

water quality standards, the current regulation ensures that the better of the past or present condition, 

at a minimum, will be maintained and protected.” Attainability is a consideration when determining the 

appropriate designated use and not the existing use. However, it is critically important how a state or 

authorized tribe determines an “existing use” which is why EPA clarified in its 2008 response to the State 

of Oklahoma and in the preambles to the proposed and final rule, how precisely an existing use is to be 

determined. In its letter to the State of Oklahoma, EPA stated that although there may be cases where 

data are insufficient or inconclusive, “It is appropriate to describe the existing uses of a waterbody in 

terms of both actual use and water quality because doing so provides the most comprehensive means of 

describing the baseline conditions that must be protected. In identifying an existing use, it is important 

to have a high degree of confidence because a state or tribe may not remove an existing use when 

revising designated uses, regardless of whether the existing use remains attainable.” 

EPA acknowledges comments providing an example of a state-specific action where EPA disapproved a 

use change from a full fish and aquatic life use to a modified aquatic life use, citing lack of data related 

to the existing use. Comments stated that the final rule, if adopted as proposed, would result in a 

different outcome regarding the determination of existing use. This specific comment is outside the 

scope of this rulemaking, as it addresses a state-specific decision. 

EPA agrees with the comment that the refinement of uses or sub-categories of uses are not required to 

be identified at a single species level, and will consider incorporating this discussion into subsequent 

guidance after the final rule is published. “Use refinement” is a broad term that encompasses any 

activity undertaken by a state or authorized tribe to review and revise the designated uses applied to its 

waters. A state/authorized tribe may refine its designated use by revising the language defining what it 

intends to protect with this particular designated use or by removing a designated use and adopting 

more specific designated uses in its place. “Subcategorization” of uses means any use refinement that 

involves subdivision of broadly applicable use categories into smaller, more homogenous groups of 

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waters with the intent of reducing variability within the group. Refined designated uses can be a tool to 

identify and capture differences in expectations based on differences in waterbody type and ecoregional 

location and they can reflect human caused conditions that cannot be remedied. The degree to which a 

state or authorized tribe should refine or subcategorize their aquatic life uses depends upon the quality 

and quantity of the available monitoring and assessment data and the power of the data to distinguish 

between different subcategories. By refining aquatic life uses, states and tribes can better organize and 

align their uses with the biological realities they observe in surface waters. In this regard, refined aquatic 

life use systems have significant advantages over more general approaches to aquatic life uses, including 

a better ability to account for differences between waters due to natural variability in waterbody types. 

Please see response essays 5.f., 5.f.i, and 5.f.ii for additional discussion on identifying the HAU. EPA’s 

WQS Handbook at Chapter 2.3 also discusses use subcategories.

Several commenters expressed general support for the interpretation regarding existing uses that EPA 

discussed in the proposal preamble and addresses in this section of the response essay (see 78 FR 

54523, September 4, 2013). EPA reiterated this interpretation in the preamble to the final rule to affirm 

its position after taking comment (see section II.B). However, EPA disagrees with the commenters who 

stated that EPA should incorporate such clarifications into regulatory language. EPA’s intention with 

respect to the narrow interpretation of the phrase “actually attained” in the definition of “existing uses” 

at section 131.10(e) is not to change or revise the requirement in 131.10(h)(1) itself. Therefore EPA has 

determined that it is unnecessary to revise the language of 13110(h)(1) and 131.3(e). 

For comments concerning antidegradation implementation methods and existing uses, please see 

response essay 7.l. For comments concerning the adoption of antidegradation implementation methods 

by rule, please see comment response 7.f.i.

C. Comments outside the Scope of the Rulemaking

Comments that took the position that EPA’s “clarifications” regarding existing uses are unnecessary 

because an existing use will be protected through the implementation of an antidegradation policy are 

outside the scope of this rulemaking. As discussed above, EPA did not change the underlying 

requirement regarding existing uses and designated use removals. Nonetheless this requirement is 

separate from the requirements in 131.12(a)(1). EPA did not propose any changes regarding 

131.12(a)(1) and therefore this comment is outside the scope of this rulemaking.

While EPA did articulate an interpretation of the words “actually attained” in the definition at 131.3(e), 

EPA did not propose or finalize any regulatory revisions to section 131.3(e), did not revise the 

requirement at section 131.10(h)(1), nor did it reopen this entire provision. Therefore, comments 

suggesting edits to section 131.3(e), such as clarifying that existing uses only apply to the uses specified 

in section 101(a)(2) of the CWA, or comments stating that EPA’s “look back” date of November 28, 1975 

is arbitrary or unrealistic from a water quality perspective, and comments that section 131.10(h)(1) 

leads to an unrealistic/unattainable category of designated uses or should be revised to allow some 

exceptions where the HAU is lower than the existing use are outside the scope of this rulemaking. 

Comments that EPA should reconsider the restrictions against removing an existing use is out of scope 

for the same reasons.

EPA received a comment concerned that states do not have extensive data to inform existing use 

decisions and that in the absence of this data and in the absence of a serious and clear EPA policy on 

how to identify existing uses “this key provision is simply ignored in nearly every regulatory action states 

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take...” As discussed above, EPA’s proposal and final only interpreted the words “actually attained” but 

did not alter the definition of existing uses at section 131.3(e) or the requirement at section 131.10(h)(1) 

such that EPA reopened its entire provision. EPA has stated its clear policy for how states and authorized 

tribes are to determine existing uses where there is insufficient or inadequate data, but comments 

suggesting that EPA must require

Several commenters noted that EPA’s regulatory revisions related to existing uses are unnecessary, 

because existing uses are already protected through sections 131.10(g), (h)(1), and section 131.12(a)(1). 

As discussed above, EPA did not change the regulatory requirement in 131.10(h)(1) that is referenced in 

131.10(g). 

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Chapter 3 – Response Essays 5.e – DU – Definitions/Terms

Essay 5.e – Designated Uses: Definitions/Terms

Comment excerpts in this Definition/Terms issue category include supplementary/introductory 

information provided by commenters without information, criticism, or suggestions pertaining to any 

elements contained in the U.S. Environmental Protection Agency’s (EPA's) proposed rule. As such, they 

are not considered to be substantive or significant comments on the proposed rule itself and, therefore, 

do not require responses. With regard to the commenters that indicate their letters contain specific 

comments on the proposed rule, see the relevant essays of this comment response document for 

responses to the substantive comment excerpts.

A. Definition of Highest Attainable Use

Numerous commenters stated that the proposed definition of highest attainable use (HAU) is overly 

broad and ambiguous. Specifically, commenters expressed that the terms “closest to the uses specified 

in section 101(a)(2) of the Act” and “best available data and information” are undefined and subjective 

in nature, and could lead to litigation over whether the HAU was properly selected. Other commenters 

indicated that the concept of HAU inaccurately implies a hierarchal relationship amongst uses, and the 

term “highest” oversimplifies state and authorized tribal use decisions, which may be more accurately 

described as use refinements. Some commenters suggested that EPA revise the definition of HAU in rule 

to specifically provide states and authorized tribes with discretion to identify the HAU that they 

determine to be most appropriate using best professional judgement (BPJ), while other commenters 

suggested deleting the definition in its entirety from the rule language and instead focusing more 

appropriately on the desired outcome of the use attainability analysis (UAA) process. 

EPA agrees with commenters that that some elements of the proposed definition could be seen as 

ambiguous and subjective and possibly lead to increased litigation. EPA agrees that it is logical to focus 

the identification of the HAU on the outcome of the UAA process. EPA also agrees that the proposed 

definition could be read to imply a hierarchy amongst uses. Commenters expressed both that “highest” 

could be misleading and imply that of the uses specified in Clean Water Act (CWA) section 101(a)(2), 

there is one “highest” use that is prioritized over all others and that within a use category, such as 

aquatic life use, there may be different needs of the aquatic ecosystem that require different criteria, 

but a more stringent criterion does not mean it is the “highest” use (e.g., cold water aquatic life vs warm 

water aquatic life).

To address these comments, EPA made a few changes to the definition. The final rule defines HAU as 

the “modified aquatic life, wildlife, or recreation use that is both closest to the uses specified in section 

101(a)(2) of the Act and attainable, based on the evaluation of the factor(s) in § 131.10(g) that 

preclude(s) attainment of the use and any other information or analyses that were used to evaluate 

attainability. There is no required highest attainable use where the State demonstrates the relevant use 

specified in section 101(a)(2) of the Act and sub-categories of such a use are not attainable.” This 

definition includes more specificity to ensure that the resulting HAU requirement is clear to states, 

authorized tribes, stakeholders and the public. First, EPA adds the term “modified” to address the 

concern of a hierarchy amongst uses. As discussed in the preamble to the final rule, adding this term 

addressed this concern by making clear that when adopting the HAU, the state or authorized tribe is 

adopting a different use within the same broad CWA section 101(a)(2) use category, if any such use is 

attainable. For example, if a state or authorized tribe removes a warm water aquatic life use, then the 

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HAU is a modified version of the warm water aquatic life use, such as a “limited warm water aquatic life 

use.” This also makes clear that if the HAU is a modified version of the aquatic life, wildlife, OR 

recreation use, then it is NOT a use that picks aquatic life use over a recreation use, thus eliminating the 

concern of prioritizing one use specified in CWA section 101(a)(2) over another. The preamble also 

makes clear that even within the same broad use category (e.g., an aquatic life use), the HAU is not 

necessarily the use with the most numerically stringent criteria. Rather, determination of the HAU must 

take into consideration the naturally expected condition for the water body or waterbody segment. 

Second, EPA’s proposed rule required that the HAU be “determined using best available data and 

information through the use attainability analysis.” EPA agrees that the term “best” could be subjective 

and ambiguous and therefore EPA replaced this language with the phrase “based on the evaluation of 

the factor(s) in § 131.10(g) that preclude(s) attainment of the use and any other information or analyses 

that were used to evaluate attainability” to add specificity and clarify that the HAU is the use that results 

from the process of determining what is not attainable.

Third, EPA retained the term “closest” even though some commenters raised an issue about subjectivity 

because after consideration EPA determined that the term best conveys the concept that the HAU is the 

“best use” within the relevant goal use category that is attainable. While EPA considered alternative 

phrasing raised in comments, such as “similar to,” EPA rejected such proposals out of concern that the 

term “similar to” is vague and may have the potential to create ambiguity. In addition, while 

commenters included “closest” when discussing their concerns about subjectivity, the revisions to the 

definition, address the issue such that the term “closest,” in context, is no longer subjective. When 

taken as a whole, today’s final rule definition makes clear that HAU the attainable use that results from 

the process of determining what is not attainable. 

Fourth, EPA added “There is no required highest attainable use where the State demonstrates the 

relevant use specified in section 101(a)(2) of the Act and sub-categories of such a use are not attainable” 

to be clear that although EPA expects such situations to be rare, the rule does not prohibit states and 

authorized tribes from removing a designated use specified in CWA section 101(a)(2) or a sub-category 

of such a use, altogether, where demonstrated to be unattainable. Please see the preamble for 

additional discussion.

Linking the definition of the HAU to the UAA demonstration of what is not attainable provides a 

reasonable definition that states and authorized tribes can use to implement the requirement at section 

131.10(g) and for EPA to reasonably use when exercising its oversight authority. For additional 

discussion on the final definition of HAU, and how the final definition addresses comments received, see 

section II.B of the preamble to the final rule and final rule language at section 131.3(m). 

Other comments contend that the HAU should be based on a state’s or authorized tribe’s BPJ and/or the

data that the state or authorized tribe determines is the best available. For a response to this comment, 

please see response essays 5.f.i. and 5.k.

EPA also disagrees with comments that the definition of HAU should be deleted in its entirety from the 

final rule, and/or that section 131.10(g) should be revised to require adoption of “all attainable uses” 

rather than the “highest attainable use.” EPA considered these options; however, the concept of HAU is 

so fundamental to the water quality standards (WQS) program that without a regulatory definition, the 

concept would not be transparent and could lead to confusion and ineffective implementation, and thus 

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less environmental protection. Having a definition is also essential for states and authorized tribes as 

they implement this requirement and for EPA to effectively and efficiently exercise its oversight role.

EPA disagrees with comments that the definition of HAU should not be included in the final rule until 

EPA has completed discussions with stakeholders about financial capability. EPA received many 

comments suggesting that EPA underestimated the proposed burden and cost of the rule. States 

specifically requested to meet with EPA to provide additional information for EPA to consider. EPA 

engaged with the states, as requested, after proposal and incorporated the information provided by 

individual states into its final economic analysis (EA). EPA’s EA and an explanation for how EPA derived 

its cost and burden estimates are documented in the Economic Analysis for the Water Quality Standards 

Regulatory Revisions (Final Rule) and can be found in the docket for this rule. For additional discussion 

on this topic, see response essay 12.a.

EPA also disagrees with comments that the definition of HAU should not be included in the final rule 

until EPA completes a Report to Congress on national progress about that success (or lack thereof) 

regarding how states and EPA have implemented the CWA’s UAA provisions. EPA does not intend to

complete any separate Report to Congress on national progress related to UAAs. However, EPA notes it 

has previously solicited and considered public input on the national WQS program in the past, including 

public comments on the 1998 Advance Notice of Proposed Rulemaking (ANPRM), a national symposium 

on designated uses held in 2002, and four workshops held in 2005 and 2006 designed to gather input 

and individual state feedback on the establishment, adjustment, and implementation of designated uses 

(78 FR 54520, 54521, September 4, 2013). This feedback served as a starting point as EPA developed its 

targeted list of issues to address in this rule, how to revise the regulations, and the rationale.

EPA disagrees with comments that the definition of HAU in the final rule does not include the 

consumption of aquatic life by humans. While the final definition does not explicitly include 

consumption of aquatic life by humans in the phrase “...modified aquatic life, wildlife, or recreation 

use...” EPA’s position is and has been for decades that the consumption of aquatic life is a use specified 

in section 101(a)(2) of the Act. EPA interprets the uses specified in section 101(a)(2) of the Act to mean 

that not only can fish and shellfish thrive in a water body, but when caught, they can also be safely 

eaten by humans. For additional discussion on this topic, please see response essay 5.k, as well as 

section II.B of the preamble.

EPA disagrees with comments that the definition of HAU should take into consideration the historical 

use of water, and that the historical use of a water should be considered along with physical, chemical, 

biological and economic factors in 131.10(g). EPA agrees that what has been actually attained in the past 

should inform designated uses, but it is unnecessary to include such factors in the definition of the HAU 

because section 131.10(h)(1) and section 131.10(g) already prohibit states and authorized tribes from 

removing a designated use if it removes an existing use. This adequately captures consideration of the 

historical use of the water. For discussion on tribal treaty rights, see subsection E. of this essay.

With regards to the comment that the regulatory definition of HAU should be expanded to encompass 

the concept of “Clean Water Act 101(a)(2) uses and/or the natural condition (or restoration of the 

integrity of the water)” EPA disagrees that such revision is necessary because the preamble to the final 

rule explains that: “The CWA does not require states and authorized tribes to adopt designated uses to 

protect a level beyond what is naturally occurring in the water body. Therefore, a state’s or authorized 

tribe’s determination of the HAU must take into consideration the naturally expected condition for the 

water body or waterbody segment.”

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B. Implementing the Highest Attainable Use Requirement

EPA agrees with comments that the HAU is linked to the UAA process and EPA’s final rule at section 

131.10(g) makes this clear by specifying that “If a State adopts a new or revised water quality standard 

based on a required use attainability analysis, the State shall also adopt the highest attainable use, as 

defined in §131.3(m).”

One commenter stated that, in some limited situations, a state or authorized tribe may only have one 

designated use category (e.g., a single aquatic life use category) and thus there is no other “lesser” 

aquatic life use to designate as the HAU. With regards to this comment, EPA notes that the preamble to 

the final rule provides multiple examples of how states and authorized tribes can articulate the HAU, 

including 1) using an existing designated use framework; 2) adopting a new statewide sub-category of a 

use; 3) adopting a new sub-category of a use that uniquely recognizes the limiting condition for a 

specific water body; and 4) designating a new or already established, broadly defined HAU and the 

criteria associated with the best pollutant/parameter levels based on the information or analysis the 

state or authorized tribe used to evaluate attainability of the designated use. In the preamble to the 

final rule, EPA clarifies that “where a state or authorized tribe does not already have a statewide use in 

their regulation that is protective of the HAU, the state or authorized tribe will need to find an approach 

that meets the requirements of the CWA and § 131.10(g). States and authorized tribes are not limited by 

the examples described in this section and can choose a different approach that aligns with their specific 

needs, as long as their preferred approach is protective of the HAU and is consistent with the CWA and 

§ 131.10.” For additional discussion, see section II.B of the preamble to the final rule.

One commenter stated that the final rule at section 131.10(g) should note that the options provided for 

articulating the HAU in the proposed rule at section 131.10(g) are not exclusive (i.e., states and 

authorized tribes are free to use other approaches). The specific sentence at issue is “To meet this 

requirement, States may, at their discretion, utilize their current use categories or subcategories, 

develop new use categories or subcategories, or adopt another use which may include a location 

specific use.” EPA has removed this statement from the final rule language to address this comment.

Please see response essays 5.f.i and 5.g for additional discussion on EPA’s response. EPA reiterates here 

and in the preamble to the final rule that states and authorized tribes may choose different approaches 

for articulating the HAU, as long as the approach chosen is consistent with the CWA and section 131.10.

Please also see section II.B. of the preamble to the final rule for discussion on example approaches for 

states and authorized tribes to consider. 

EPA agrees with comments that the preamble to the final rule should provide additional examples of 

how the HAU may be identified using the factors at section 131.10(g). EPA refers the commenter to the 

examples provided in section II.B of the preamble to the final rule.

EPA disagrees with the comments that states and authorized tribes will need to conduct two UAAs in 

order to implement the HAU: one to remove the unattainable 101(a)(2) designated use, and a second to 

determine the HAU. In fact, the same UAA that determines what is not attainable is used to determine

the HAU, as described in the final HAU definition at section 131.3(m). EPA also received comment that 

the commenter was concerned with how an HAU is identified based on the factors at section 131.10(g) 

if the factors are intended to determine what is not attainable rather than what is attainable. EPA agrees 

and consistent with the commenters request that EPA “modify the language of the HAU to place it in its 

proper context” and provide examples, EPA has both modified the HAU to place it in the context of how 

the UAA is used to determine the HAU and provides an example of how a UAA would inform 

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identification of the HAU. EPA will consider providing additional examples in guidance after the final rule 

is published.

EPA disagrees with the comment that states and authorized tribes will need to designate every water 

body as a cold water fishery because such a use is considered the HAU, even if in reality such a use is not 

naturally attainable in most waters. EPA refers the commenter to the definition of HAU in the final rule 

at section 131.3(m), which clearly states that the HAU is the use “both closest to the uses specified in 

section 101(a)(2) of the Act and attainable, based on the evaluation of the factor(s) in § 131.10(g) that 

preclude(s) attainment of the use.....”(emphasis added). In addition, EPA added the following language 

to the preamble to the final rule: “The CWA does not require states and authorized tribes to adopt 

designated uses to protect a level beyond what is naturally occurring in the water body. Therefore, a 

state’s or authorized tribe’s determination of the HAU must take into consideration the naturally 

expected condition for the water body or waterbody segment.” Please see EPA’s preamble to the final 

rule at section II.B. for additional discussion on this point and preamble language.

EPA disagrees with comments that adopting the HAU and supporting criteria are overly burdensome for 

states and authorized tribes. EPA received many comments suggesting that EPA underestimated the 

proposed burden and cost of the rule. States specifically requested to meet with EPA to provide 

additional information for EPA to consider. EPA engaged with the states, as requested, after proposal 

and incorporated the information provided into its final EA. EPA’s EA and an explanation for how EPA 

derived its cost and burden estimates are documented in the Economic Analysis for the Water Quality 

Standards Regulatory Revisions (Final Rule) and can be found in the docket for this rule. Please see 

response essays 5.f.i. and 12.a. and 12.b.

EPA disagrees with comments that implementing the HAU requirement will lead to the adoption of an 

impractical number of nuanced sub-categories and associated criteria. How detailed a state or 

authorized tribe wishes to be with its designated uses is solely at the discretion of the state or 

authorized tribe, as long as the adopted designated use protects the HAU, consistent with section 

131.10(g). States and authorized tribes do not need to designate very specific sub-categories (e.g., at the 

species-specific level) if there is another approach that satisfies the HAU requirement, although, in some 

cases, such an approach may better communicate the goals and objectives for a water body to the

state’s or authorized tribe’s public.

One commenter asserted that giving states discretion to determine the HAU would alter the court’s 

standard of review. To the extent that the commenter suggested that the decision regarding what is the 

HAU is within the sole discretion of the state, EPA does not agree. EPA’s rule provides a definition and 

sets basic requirements for adoption of the HAU which the state or authorized tribe will need to meet, 

subject to stakeholder input and EPA’s review and approval. EPA cannot speak to the standard of review 

in all state/authorized tribal courts, however the Administrative Procedure Act (APA) standard would 

apply to the reviewability of EPA’s final agency action on a new or revised HAU.

EPA disagrees with comments that the HAU requirement will result in degradation of water quality in 

the United States, as well as degradation of state environmental agency oversight. The commenter did 

not provide any examples or information to support this statement. EPA reiterates that removing a use 

specified in section 101(a)(2) of the Act and subcategories of such uses and the applicable criteria 

altogether, without adopting the HAU (and the criteria that protect the HAU) does not serve the goals of 

the CWA or enhance the quality of the water consistent with CWA sections 101(a)(2) and 303(c)(2)(A). 

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EPA disagrees with comments that the HAU must be determined for all waters, and refers the 

commenter to the final rule at section 131.10(g), which clearly links the requirement to adopt the HAU 

to instances when a state or authorized tribe conducts a UAA as specified in section 131.10(j).

For a response to comments regarding how the HAU affects the CWA given authority and discretion to 

consider “use and value” when designating uses, please see response essay 5.k.

C. Definition of Clean Water Act 101(a)(2) Uses

EPA agrees with the comment that it should clearly define what uses constitute a use specified in 

section 101(a)(2) of the Act. The preamble to the final rule clarifies the terms “uses specified in section 

101(a)(2) of the Act” and “sub-category of a use specified in section 101(a)(2) of the Act” (see section 

II.B of the preamble to the final rule). In addition, EPA provides a regulatory definition for the term “non101(a)(2) use” in the final rule at section 131.3(q).

EPA agrees with the comment that it should include preamble discussion clarifying the meaning of fish 

and aquatic life uses, as well as clarifying that incidental, occasional or opportunistic presence of a 

limited number of individual aquatic organisms is not equivalent to a full CWA 101(a)(2) use. The 

preamble to the final rule clarifies the terms “uses specified in section 101(a)(2) of the Act” and “subcategory of a use specified in section 101(a)(2) of the Act” (see section II.B of the preamble to the final 

rule). In the example provided by the commenter, the incidental, occasional or opportunistic presence 

of a limited number of individual aquatic organisms would not provide for the protection and 

propagation of fish, shellfish and wildlife and thus would not be considered to be a full 101(a)(2) use. 

However, as discussed in response essay 5.d, when designating uses, states and authorized tribes need 

to consider a number of factors in addition to the existing use, such as the current use that is attained, 

as well as the use(s) that may be attainable in the future, and considerations of threatened or 

endangered species. If several fish are observed utilizing a water body on a transient, temporary basis, it 

may be reasonable to expect similar occurrences in the future, and therefore an aquatic life use 

designation may be attainable and appropriate. States and authorized tribes should engage their public 

in determining the HAU for such a water body even if it is a subcategory of a use specified in section 

101(a)(2) of the Act.

With regards to the comment that the requirement to adopt the HAU is invoked when a state or 

authorized tribe conducts a UAA and subsequently adopts a use that is not protective of 101(a) uses, 

EPA is unclear how the commenter is defining the phrase “not protective of 101(a) uses.” EPA clarifies 

that the requirement to adopt the HAU is limited to when section 131.10(j) requires a UAA.

EPA disagrees with comments that the final rule language should use the term “fishable and 

swimmable” in lieu of the phrase “uses specified in section 101(a)(2) of the Act.” EPA also disagrees that 

the final rule at section 131.3 should define the terms “fishable” and “swimmable.” The phrase “uses 

specified in section 101(a)(2) of the Act” is directly tied to the relevant section of the CWA, which states: 

“......it is the national goal that, wherever attainable, an interim goal of water quality which provides for 

the protection and propagation of fish, shellfish and wildlife and provides for recreation in and on the 

water be achieved....” By so formally short-handing the phrase to “fishable and swimmable,” EPA would 

not be fully describing the intent and scope of the CWA section 101(a)(2). 

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EPA disagrees with commenters who state that there is no basis to include fish consumption as a use 

specified in section 101(a)(2) of the Act. For additional discussion on this topic, please see response 

essay 5.k, as well as section II.B of the preamble. EPA also disagrees with the commenter who stated 

that the final rule should clarify that no UAA is required when removing a fish consumption use. For 

additional discussion on this topic, please see response essay 5.j, as well as section II.B of the preamble.

D. Use Attainability Analyses

With regards to the comments suggesting revisions to the definition of a UAA at section 131.3(g), these 

comments are outside the scope of this rulemaking. EPA did not propose and is not finalizing any 

revisions to the definition of a UAA at section 131.3(g).

With regards to the comment that EPA has historically made it difficult for states and authorized tribes 

to pursue UAAs, the commenter did not provide any specific information or examples to support this 

statement. However, EPA notes it does not and would not force a state or authorized tribe to conduct a 

UAA and downgrade its 101(a)(2) related designated uses (consistent with CWA section 510). Such a 

decision is at the discretion of the state or authorized tribe, as long as its actions satisfy minimum CWA 

requirements and the federal regulations. Where states and authorized tribes submit a designated use 

revision based on a UAA, EPA must approve or disapprove it in a timely manner. EPA can only approve a 

use change if it meets the requirements of the CWA and the WQS regulation.

E. Other

EPA acknowledges and appreciates commenters who expressed support for the inclusion of the HAU 

requirement.

EPA disagrees with comments that the concept of HAU is not supported by the CWA, as well as 

comments that the HAU is an unreasonable intrusion on state flexibility. For additional discussion on this 

topic, see response essay 5.k.

For a response to comments on HAU and triennial reviews, please see response essay 5.f.i.

EPA disagrees with the commenter who suggests that this rulemaking undermines the Congressional 

intent under the CWA for states (including U.S. territories and authorized tribes) to have the primary 

responsibility to set WQS (including designated uses), and that EPA’s HAU requirement is contrary to 

CWA section 101(b). EPA acknowledges that the CWA creates a partnership between states and 

authorized tribes and EPA, by assigning states and authorized tribes the primary role of adopting WQS 

(CWA sections 101(b) and 303) and EPA the critical oversight role of promulgating regulations as 

necessary to implement the CWA (pursuant to CWA section 501), approving and disapproving state- or 

authorized tribe-adopted WQS, and promulgating federal WQS for state and tribes where appropriate. 

For additional discussion on this topic, see response essay 3.a and 5.k. 

With regard to the commenters suggesting that EPA further revise the rule to include the term “and 

tribe(s)” in every instance that the regulation uses “State(s)”, EPA disagrees. The addition of the words 

“and tribe(s)” is not appropriate in some cases because only Federally recognized tribes that EPA has 

found eligible, pursuant to CWA section 518(e) and Title 40 of the Code of Federal Regulations (CFR) 

section 131.8, have the authority to administer a CWA WQS program. Further, the addition of the words 

“and tribe(s)” is not necessary because the regulation at 131.3(j) defines “States” for the purposes of 

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40 CFR Part 131 as including “The 50 States, the District of Columbia, Guam, the Commonwealth of 

Puerto Rico, Virgin Islands, American Samoa, the Commonwealth of the Northern Mariana Islands, and 

Indian Tribes that EPA determines to be eligible for purposes of the water quality standards program.”

While the final rule does not add the term “and tribe(s)” throughout the regulation, as commenters 

suggested, EPA did review the use of the term “states” throughout the regulation to ensure that it was 

used appropriately and consistently. As described in section II.A of the preamble to the final rule, EPA 

found that use of the term “States” in section 131.22(b) did not accurately describe the scope of waters 

for which CWA section 303(c)(4)(B) provides authority to the EPA Administrator. Thus, the final rule 

removes the word “States” from section 131.22(b), and instead uses the term “navigable waters,” 

consistent with CWA section 303(c)(4). EPA did revise the preamble language to say “states and 

authorized tribes” wherever appropriate, and has used the phrase “states and authorized tribes” 

throughout these responses to comments. 

With regards to the comments that uses should not be downgraded to the extent that the downgrade

would result in a lack of protection for treaty-reserved rights, resources, and tribal member health, EPA

acknowledges the United States’ government-to-government relationship with and trust responsibility 

to federally recognized Indian tribes, and that EPA must ensure its actions do not conflict with tribal 

treaty or other reserved rights. EPA remains fully committed to engaging tribes as sovereign 

governments with a right to self-governance. To the extent the commenter is concerned that a use 

revision or “downgrade” may remove an existing tribal use, EPA notes that the existing use provisions at 

sections 131.10(g) and (h)(1) still apply. EPA’s final rule did not make any revisions to the existing use 

provisions. Where a tribe is concerned that a state action may impact an existing use, a tribal treaty 

right, or other reserved right, the tribe may provide comments to the state during their public comment 

period for the state's consideration. The tribe may also provide such comments to EPA after the state 

has adopted its WQS. 

EPA received a comment that was concerned that EPA’s statements about identifying existing uses 

where data is lacking or insufficient was authorizing or encouraging states and authorized tribes to 

adopt new or amended WQS “when not all the ‘necessary’ scientific data needed to support the 

standards has been developed or vetted.” The commenter is confusing designated uses with existing 

uses. A UAA, which is a structured scientific assessment of the factors affecting the attainment of the 

use, is required when modifying or removing 101(a)(2) designated uses per section 131.10(j). As 

described in the preamble to the final rule, existing uses are uses that have been actually attained on or 

after November 28, 1975. EPA recognizes, however, that all the necessary data may not be available to 

determine whether the use actually occurred or the water quality to support the use has ever been 

attained. In those situations, EPA provides flexibility to states and authorized tribes to evaluate the 

strength of the available data and information where data may be limited, inconclusive, or insufficient.

For additional discussion on existing uses, please see response essay 5.d. When designating uses, the 

regulations allow states and authorized tribes to designate the uses specified in section 101(a)(2) of the 

Act without conducting a UAA and thus states and authorized tribes can choose to designate such uses 

without first confirming with data that such uses are indeed attainable. Please see response essay 5.i.

for additional discussion.

EPA acknowledges the comment that “the HAU may be both a new use designation (or a sub-category of 

the use) and its site-specific standard”. EPA does not understand the comment as written, but assumes 

the commenter may be confusing the concept of a “site-specific criterion” with a “location-specific use.” 

A site-specific criterion is designed to protect the current, unchanged designated use, but the criterion 

value may be different from the statewide or otherwise applicable criterion because it is tailored to 

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account for site-specific conditions (but is still protective of the applicable designated use on the water 

body in question). A location-specific use, on the other hand, is best described as a sub-category of a use 

that uniquely recognizes the limiting condition for a specific water body and the use that can be attained 

as a result. 

With regards to the comment that adopting the HAU could subject permit holders on a water body to 

discharge limits at or below background levels in the receiving waters, EPA observes that permits must 

include limits as stringent as necessary to meet WQS, and that EPA policy acknowledges that states and 

authorized tribes may establish site-specific or generally applicable aquatic life criteria equal to natural 

background conditions. EPA is unable to say, at this point, how states will implement their permitting 

programs in the future in light of this requirement (e.g., states could derive limits equal to criteria at 

end-of-pipe, or higher limits based on dilution and/or a mixing zone, include a compliance schedule (CS), 

adopt a variance, implement trading, among other options). Thus, this comment is outside the scope of 

this rulemaking action.

EPA acknowledges the comment that it should clarify that a high quality antidegradation review (i.e., a 

“Tier 2” review) is not required in states that apply antidegradation review on a waterbody-bywaterbody basis with respect to a “highest attainable use” and the supporting criteria that are 

established after a UAA or variance. EPA is unclear how the commenter is connecting the HAU with Tier 

2 reviews. Tier 2 reviews are conducted where waters quality exceeds levels necessary to support the 

uses specified in section 101(a)(2) of the Act. If a state or authorized tribe decides that a particular water 

body is not a Tier 2 water based on the waterbody-by-waterbody approach, then a Tier 2 review is not 

required. Alternately, a state or authorized tribe could decide the water gets Tier 2 protection, and 

conduct a Tier 2 review for parameters with assimilative capacity because levels exceed that necessary 

to support the uses specified in CWA section 101(a)(2). Please see response essay 7.d.i and 7.d.ii for 

additional discussion on identification of high quality waters and 7.d.iii for additional discussion on 

conducting Tier 2 reviews.

One commenter argues that the term “sound scientific rationale” in section 131.5(a)(2) is an ambiguous

and subjective point of reference and may interfere with the ability of states and authorized tribes to 

use narrative criteria. For a response to this comment, please see response essay 10.a.

For a response to comments regarding the criteria to protect the HAU, please see response essay 5.f.ii.

For a response to comments that an HAU is unnecessary in instances where a UAA (or variance) is based 

on section 131.10(g)(6) because states and authorized tribes would still impose technology-based 

limitations, please see response essay 5.f.i.

For a response to comments that the HAU requirement should not be finalized, please see the preamble 

at section II.B for an explanation for why EPA is finalizing this requirement.

In response to commenters suggesting that designating a water for a use specified in section 101(a)(2) 

would interfere with a state’s or authorized tribe’s ability to designate an industrial use, EPA disagrees. 

EPA’s rule allows states and authorized tribes to designate waters for both the uses specified in section 

101(a)(2) and an industrial use or any other non 101(a)(2) uses, consistent with EPA’s regulation, if such 

uses are appropriate.

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Essay 5.f – Designated Uses: HAU

With regards to the commenter who stated that the definition of highest attainable use (HAU), as 

proposed, could result in litigation over what is the HAU, the U.S. Environmental Protection Agency 

(EPA) notes that the final rule defines HAU as the “modified aquatic life, wildlife, or recreation use that 

is both closest to the uses specified in section 101(a)(2) of the Act and attainable, based on the 

evaluation of the factor(s) in § 131.10(g) that preclude(s) attainment of the use and any other 

information or analyses that were used to evaluation attainability. There is no required highest 

attainable use where the State demonstrates the relevant use specified in section 101(a)(2) of the Act 

and sub-categories of such a use are not attainable.” This definition includes specific terms to ensure 

that the resulting HAU is clear to states, authorized tribes, stakeholders and the public. EPA revised the 

definition taking into account the reasons for why commenters felt there may be more litigation, such as 

ambiguity and/or subjectivity. EPA revised the definition to focus on the analysis done as part of the use 

attainability analysis (UAA) and how that informs the HAU. For additional discussion on this topic, see 

response essay 5.e, as well as section II.B of the preamble to the final rule. 

For comments regarding how much discretion states and authorized tribes have when determining the 

appropriate HAU, please see response essays 5.e., 5.f.i, and 5.g. as well as section II.B of the preamble to 

the final rule.

For questions or comments regarding the different approaches a state or authorized tribe can utilize 

when adopting the HAU and whether there is an exclusive list or whether the examples EPA provided 

are non-exclusive, please see response essay 5.f.i.

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Essay 5.f.i – Designated Uses: Adopting HAU

A. General Comments

The U.S. Environmental Protection Agency (EPA) acknowledges and appreciates the general support 

expressed by several commenters for the requirement in the final rule to adopt the highest attainable 

use (HAU), once a required use attainability analysis (UAA) is conducted per section 131.10(j).

With regard to the comment that the requirement to adopt the HAU requires states and authorized 

tribes to expend limited resources to rebut the presumption of attainability, EPA clarifies that states and 

authorized tribes are only required to adopt the HAU when they adopt new or revised water quality 

standards (WQS) based on a required UAA per section 131.10(j). EPA does not and cannot force a state 

or authorized tribe to conduct a UAA in order to downgrade its designated uses. Such a decision is at the 

discretion of the state or authorized tribe. For additional discussion on the rebuttable presumption, see 

response essay 5.i.

EPA disagrees with the comment that waters may be subject to HAU designations regardless of the 

circumstances of individual water bodies. The requirement to adopt the HAU is not a universal 

requirement, but rather is limited to instances when states and authorized tribes conduct a UAA per 

section 131.10(j). Furthermore, in the final rule, EPA specifically links the HAU to an “evaluation of the 

factor(s) in § 131.10(g) that preclude(s) attainment of the use and any other information or analyses 

that were used to evaluate attainability.” Therefore, identification and adoption of the HAU is not a 

subjective decision. For additional discussion on this topic, see response essay 5.e.

With regard to the comment that EPA should not place new regulatory hurdles before states and 

authorized tribes that are trying to accommodate natural conditions into their regulatory schemes, EPA 

added the following language to the preamble to the final rule: “The CWA does not require states and 

authorized tribes to adopt designated uses to protect a level beyond what is naturally occurring in the 

water body. Therefore, a state’s or authorized tribe’s determination of the HAU must take into 

consideration the naturally expected condition for the water body or waterbody segment.” See section 

II.B of the preamble to the final rule.

With regard to the comment that EPA should require sufficient clarity about designated uses, in 

particular those uses that are not recreationally or commercially important, the commenter did not 

provide any recommendations for what constitutes “sufficient” clarity for designated uses. However, 

EPA notes that the Clean Water Act (CWA) creates a partnership between states, authorized tribes and 

EPA by assigning states and authorized tribes the primary role of adopting WQS (CWA sections 101(b) 

and 303) and EPA an oversight role.

With regard to the comment that the HAU requirement is unnecessary in instances where a UAA (or 

variance) is based on section 131.10(g)(6) because states and authorized tribes would still impose 

technology-based limitations. EPA disagrees that technology based limitations established consistent 

with CWA section 301(b) and 306 will always equate to the HAU. In instances where a state or 

authorized tribe has shown that attaining the designated use will cause a substantial and widespread 

social and economic impact, it is possible that the HAU will be achieved by implementing technology 

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based limits. However, there may be situations where the HAU is something better than what can be 

achieved by technology based limitations.

B. Definition of Highest Attainable Use

EPA agrees with comments that the proposed definition of HAU could be viewed as ambiguous, uses 

overly subjective terminology (e.g., “highest” attainable use), may unintentionally imply a hierarchy of 

uses, and could result in litigation over whether the HAU was properly selected. EPA disagrees with the 

comments that EPA should revise the definition of HAU to specifically provide states and authorized 

tribes with discretion to identify the HAU that they determine to be most appropriate using best 

professional judgement (BPJ), as well as discretion to determine what constitutes “best available data.”

For EPA’s response to these comments, see response essay 5.e.

C. Adopting the Highest Attainable Use

Several commenters expressed support for the proposed rule language in section 131.10(g) allowing 

states and authorized tribes discretion to utilize their current use categories or sub-categories, develop 

new use categories or sub-categories, or adopt another use which may include a location-specific use. 

These approaches are still available to states and authorized tribes, as well as a fourth approach 

outlined in the preamble to the final rule; however, EPA notes that this particular sentence has been 

removed from the final rule language in section 131.10(g). Instead, the preamble to the final rule 

emphasizes that states and authorized tribes are not limited by the examples provided in the preamble 

and can choose a different approach that aligns with their specific needs, as long as their preferred 

approach is protective of the HAU and is consistent with the CWA and section 131.10. The preamble to 

the proposed rule also provides several specific examples of how states have articulated the HAU in 

their regulations. It is reasonable for EPA to finalize this rule language because the CWA provides states 

and authorized tribes the discretion to determine the best way to meet the CWA and regulatory 

requirements. As discussed in the preambles to the proposed rule and the final rule, EPA is not 

interested in dictating how the state or authorized tribe manages its designated use structures but is 

only concerned that the states or authorized tribes are consistent with the CWA and regulatory 

requirements before EPA can approve any WQS revision. EPA’s HAU requirement builds on the already 

established UAA process that states and authorized tribes must go through to remove or revise a use 

specified in CWA section 101(a)(2) or subcategory of such a use. Thus, once states and authorized tribes 

identify that a use specified in CWA section 101(a)(2) or a subcategory of such a use is not attainable, it 

uses the same information to show what it is attainable. Defining HAU in this way is efficient because 

states and authorized tribes are using the same analysis and information when determining what WQS 

to remove and what WQS to adopt. In addition, it also provides EPA with an objective standard by which 

to review state/authorized tribal WQS revisions. This approach ensures that states’/authorized tribes’ 

WQS continue to serve the objective and goals of the Act to exercise its oversight role to approve or 

disapprove WQS. For additional discussion on this topic, see response essay 5.g.

As stated above, EPA deleted the last sentence in the proposed revisions to section 131.10(g): “To meet 

this requirement, States may, at their discretion, utilize their current use categories or subcategories, 

develop new use categories or subcategories, or adopt another use which may include a location 

specific use.” A number of commenters expressed concern that this sentence implied that states and 

authorized tribes were limited to these three specific options for articulating the HAU, and would be 

unable to articulate the HAU in a different way. This was not EPA’s intent; rather, EPA’s intent is to 

provide states and authorized tribes with discretion to pick an option for articulating the HAU that works 

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best for them, provided that the selected option still meets the HAU requirement. In addition, in 

considering this issue further, EPA realized the proposed regulatory language could result in states or 

authorized tribes not adopting a modified 101(a)(2) use even if attainable if the state’s or tribe’s existing 

use categorization schemes did not include such a modified use. EPA’s position is that such a result 

would not be consistent with the purpose and objectives of the HAU requirement. As discussed in the 

preamble to the proposed rule, meeting the HAU requirement may not require modifications to their 

statewide/authorized tribe-wide use categorization schemes as long as the state or authorized tribe 

meets the HAU requirement.

With regard to the comment that, in the context of articulating the HAU, EPA should drop its implied 

encouragement to states and authorized tribes to make water quality impairments more or less 

permanent (e.g., “CSO-impacted use”), EPA disagrees. EPA is not encouraging states and authorized 

tribes to make water quality impairments permanent, but rather is offering an option where a state or 

authorized tribe may adopt a new sub-category of a use that uniquely recognizes the limiting condition 

for a specific water body, should such sub-category be justified through an appropriate UAA per sections

131.10(g) and (j).

With regard to the comment that EPA should clarify that states seeking to downgrade designated uses 

must establish the HAU even if that means establishing new use categories, as well as the comment that 

EPA should clarify that states and authorized tribes are required to adopt a location-specific use or 

develop new use categories if existing use categories or sub-categories are insufficient to protect the 

HAU, EPA includes the following language in the preamble to the final rule: “Where a state or authorized 

tribe does not already have a statewide use in their regulation that is protective of the HAU, the state or 

authorized tribe will need to find an approach that meets the requirements of the CWA and 

§ 131.10(g).”

With regard to the comment requesting clarification on the difference between site-specific criteria and 

a location-specific use, a site-specific criterion is designed to protect the current, unchanged designated 

use, but the criterion value may be different from the statewide or otherwise applicable criterion 

because it is tailored to account for site-specific conditions. A location-specific use, on the other hand, is 

best described as a new sub-category of a use that uniquely recognizes the limiting condition for a 

specific water body. For example, an “aquatic life use limited by naturally high levels of copper” is a 

location-specific use that describes a water body where the statewide copper criterion that protects for 

the aquatic life use is not attainable, but criteria for all other pollutants are still being attained.

EPA disagrees with the comment that the concept of HAU implies that there is always an attainable use. 

The final regulation does not prohibit states and authorized tribes from removing a designated use 

specified in CWA section 101(a)(2) or a subcategory of such a use, altogether, where demonstrated to 

be unattainable. For example, a state or authorized tribe may remove an aquatic life use if it can 

demonstrate through a UAA that no aquatic life use or subcategory of aquatic life use is attainable. EPA 

expects such situations to be rare; however, to clarify that this outcome is possible, EPA adds the 

following to the definition of HAU in the final rule at section 131.3(m): “There is no highest attainable 

use where the State [or authorized tribe] demonstrates the relevant use specified in section 101(a)(2) of 

the Act and subcategories of such a use are not attainable.”

EPA disagrees with the comment that identifying the HAU requires a significant amount of additional 

data, such an evaluation of non WQS-related parameters including basin geomorphic processes, 

landscape assessments, and hydrologic modeling. EPA added the phrase “based on the evaluation of the 

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factor(s) in § 131.10(g) that preclude(s) attainment of the use and any other information or analyses 

that were used to evaluate attainability” to the definition of HAU in the final rule to clarify that the HAU 

is the use that results from the process of determining what is attainable, and is unrelated to an 

evaluation of non WQS-related parameters.

EPA disagrees with the comment that developing new use categories and associated water quality 

criteria could be overly burdensome, and states are essentially being required to develop unique water 

quality criteria for each use change. For additional discussion on this topic, see response essay 5.e.

EPA disagrees with the comment that adopting the HAU requires states and authorized tribes to take 

UAAs to a species-specific level, and/or adopt finely divided subcategories. How detailed a state or 

authorized tribe wishes its designated uses to be is solely at the discretion of the state or authorized 

tribe, as long as the use reflects the HAU consistent with EPA requirements. With regard to the 

comment that it is unclear what use a state or authorized tribe will be compelled to adopt as the HAU if 

the state or authorized tribe only has broad use categories, EPA provided several examples in the 

preamble to the proposed rule of how a state or authorized tribe may articulate the HAU (i.e., using an 

existing designated use category, adopting a new statewide sub-category, or adopting a new subcategory of a use that uniquely recognizes the limiting condition for a specific water body). In the 

preamble to the final rule, EPA provides a fourth alternative to articulate the HAU (i.e., essentially 

articulating that the HAU reflects whatever use is attained when the most protective, attainable criteria 

are achieved). EPA also provides, in the preamble to the final rule, several additional, real life examples 

of how states and authorized tribes have articulated the HAU, and clarifies that states and authorized 

tribes are not limited by the provided examples and can choose a different approach that aligns with 

their specific needs, as long as their preferred approach is protective of the HAU and is consistent with 

the CWA and section 131.10. For additional response to this comment, see response essay 5.e.

EPA both agrees and disagrees with the commenters who question the need to create new subcategories of designated uses when adopting the HAU. States and authorized tribes have discretion in 

choosing the best approach to articulate the HAU, provided the approach is consistent with the CWA 

and section 131.10. If a state or authorized tribe has an appropriate sub-category in their designated use 

framework that protects for the HAU, then a new sub-category is not necessary. However, EPA clarifies

that where a state or authorized tribe does not already have a use in their regulation that is protective 

of the HAU, the state or authorized tribe will need to find an approach that meets the requirements of 

the CWA and section 131.10(g). 

One commenter provided edits to the suggested approaches outlined in the preamble for how states 

and authorized tribes can articulate the HAU. EPA reiterates that these approaches are only examples, 

and states and authorized tribes have flexibility in choosing their preferred approach, provided that the 

approach is protective of the HAU and is consistent with the CWA and section 131.10. EPA also notes 

that it provides a fourth suggested approach for articulating the HAU in the preamble to the final rule, as 

well as some examples of how states have protected the HAU in specific circumstances (e.g., effluent 

dependent waters and tailoring site-specific criteria to protect the HAU). See section II.B of the 

preamble to the final rule for additional discussion. 

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EPA disagrees with commenters that argue that predicting what is attainable in the future, after 

achievable gains in water quality are considered, places an impossible burden on states, authorized 

tribes, and regulated stakeholders. EPA also disagrees with commenters that states and authorized 

tribes should not be required to look at future attainable uses based on things such as the potential 

effectiveness of best management practices (BMPs). Based on comments received, EPA recognizes that 

its preamble to the proposed rule may have created some confusion regarding this issue. EPA’s 

preamble to the proposed rule said “When conducting this review and soliciting input from the public 

states and tribes should consider not only what is currently attained...” (See 78 FR 54523–24, September 

4, 2013) [emphasis added]. To be clear, EPA’s final rule does not place a new requirement to “predict 

what is attainable in the future”. The notion that considering attainability involves a prospective analysis 

has long been a part of EPA’s prior existing regulations. EPA’s definition of designated use at section 

131.3(f), untouched by today’s rule, defines designated uses as “those uses specified in water quality 

standards for each water body or segment whether or not they are being attained.” The fundamental 

component of 131.10(g), unchanged by today’s rule, requires that a state or authorized tribe 

demonstrate that “attaining the designated use is not feasible” based on one of the six regulatory 

factors. When discussing the factors at 131.10(g), EPA explained in its 1998 Advance Notice of Proposed 

Rulemaking (ANPRM) that “[t]he use removal criteria were included in the regulation to address those 

circumstances where the attainability of certain uses would be precluded by conditions over which the 

water quality protection provisions in the regulation had little or no control.” Water Quality Standards 

Regulations: Advance Notice of Proposed Rulemaking, 63 Fed. Reg. 36742, 36754 (July 7, 1998). 

Therefore, it is reasonable to interpret the words “attaining the designated use is not feasible” as 

indicating that this evaluation is forward looking to confirm that there are no additional steps available 

in the future to address the relevant conditions before removing protections for those goals on a 

relatively permanent basis.1 EPA notes that it’s interpretation is also supported by 131.10(d) and (h)(2) 

that discusses attainability as those uses that “can be achieved” or “will be attained” by imposing 

technology requirements and cost effective and reasonable BMPs. To ensure clarity, EPA’s preamble to 

the final rule says: “When conducting a UAA and soliciting input from the public, states and authorized 

tribes need to consider not only what is currently attained ...” [emphasis added].

In its 1998 ANRM, EPA explained that the prior existing requirements at section 131.10(g):

[M]ake a distinction between existing and designated uses and set out specific requirements to 

ensure protection of these two broad use categories. Designated uses are defined as those uses 

specified in water quality standards for each water body or segment whether or not they are 

being attained. EPA interprets existing uses as those uses actually attained in the water body on 

or after November 28, 1975 (the date of EPA's initial water quality standards regulation), 

whether or not they are included in water quality standards. 40 CFR 131.3(e). Designated uses 

focus on the attainable condition while existing uses focus on the past or present condition. 

Section 131.10 then links these two broad use categories in a manner which intends to ensure 

that States and Tribes designate appropriate water uses, reflecting both the existing and 

attainable uses of each water body...

1 Use changes are not strictly permanent because section 131.20(a) requires states and authorized tribes to 

reevaluate waterbody segments that do not include the uses specified in section 101(a)(2) of the Act to determine 

if new information has become available indicating that such uses are attainable. If so, then states and authorized 

tribes are required to revise their WQS accordingly.

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It is in designating uses that States and Tribes establish the environmental goals for their water 

resources, and it is in designating uses that States and Tribes are allowed to evaluate the 

attainability of those goals. Because water quality standards perform the dual function of 

establishing water quality goals and ultimately serving as the regulatory basis for water qualitybased treatment controls and strategies, typically, although not exclusively, via water quality 

criteria protecting those uses, a State or Tribe often weighs the environmental, social and 

economic consequences of its decisions in designating uses. The regulation allows the State or 

Tribe some flexibility in weighing these considerations and adjusting these goals over time. 

Reaching a conclusion on the uses that appropriately reflect the potential for a water body, 

determining the attainability of those goals, and appropriately evaluating the consequences of a 

designation, however, can be a difficult and controversial task. Appropriate application of this 

process involves a balancing of environmental, scientific, technical, and economic and social 

considerations as well as public opinion and is therefore one of the most challenging areas of 

the current regulation.

To direct this decision making-process, the regulation establishes requirements that must be 

followed when designating uses or concluding that attaining a use is infeasible. When 

performing this attainability analysis, a State or Tribe considers physical, chemical, biological and 

economic factors that may limit the potential for achieving the goal use.

This clear differentiation articulated in the first paragraph shows that existing uses are about the past 

and the present whereas designated uses are about the future desired conditions for a water that may 

or may not be currently attained. The use of the term “potential” also makes clear that the evaluation of 

attainability has never been limited to what is attainable currently.

This approach is reasonable because WQS apply to the water body as a whole, regardless of the source 

of pollution. Therefore, because both point and nonpoint sources (NPS) of pollution can affect use 

attainability, it is important for states and authorized tribes to evaluate the impact that both point and 

NPS controls might have on water quality prior to removing a use. When determining whether a 

designated use is attainable, states and authorized tribes need to consider whether the use could be 

attained by implementation of cost-effective and reasonable BMPs for NPS controls water body wide.

This does not mean that the regulations require implementation of such BMPs. Regulation of NPS

remains at the discretion of states and authorized tribes. However, this choice does not negate the 

requirements of the CWA and regulation which is why the establishment of WQS is not affected by this 

choice nor is the assessment of whether a water is meeting its WQS consistent with CWA section 303(d).

For additional discussion, see 78 FR 54535, 54536, September 4, 2013. 

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In establishing goals, states and authorized tribes consider not only what is attainable now, but what 

objectives they may have for a water body in the future. When removing or revising designated uses 

that reflect uses specified in section 101(a)(2) of the Act or subcategories of such uses, the UAA 

identifies issues that limit the potential of that water body to meet its designated use, consistent with 

section 131.10. EPA’s definition of HAU at section 131.3(m) clearly links the identification of the HAU to 

this analysis of attainability and thus it is an inherent function of the process that the HAU identifies the 

projected potential for the water body. As discussed earlier, the notion of evaluating the potential 

attainability of a water is not a new requirement and thus the addition of the HAU requirement should 

not significantly increase the burden of the use revision process. Any incremental burden associated

with the HAU requirement has been accounted for in EPA economic analysis (EA). Please see EPA’s EA

and an explanation for how EPA derived its cost and burden estimates are documented in the Economic 

Analysis for the Water Quality Standards Regulatory Revisions (Final Rule) and can be found in the 

docket for this rule. For additional discussion on burden, see response essay 12.a. States have a variety 

of options available to them when determining the HAU. See EPA’s preamble to the final rule for 

additional discussion. For additional discussion on the highest attainable condition (HAC), see response 

essay 8.c which discusses the HAC in the context of WQS variances.

EPA agrees with the comment that the requirement to identify the HAU is tied exclusively to the UAA 

process. EPA refers commenters to the final rule text at section 131.10(g), which provides “if a State 

adopts a new or revised water quality standard based on a required use attainability analysis, the State 

shall also adopt the highest attainable use, as defined in §131.3(m).” A UAA is defined under EPA’s 

regulations as “a structured scientific assessment of the factors affecting the attainment of the use 

which may include physical, chemical, biological and economic factors as described in 131.10(g).”

With regard to the comment that the final rule requires states and authorized tribes to designate the 

HAU without inclusion of agricultural interests, EPA clarifies that the HAU is established without regard 

to the source of potential pollution (e.g. point source or NPS such as agriculture). Once the HAU is 

adopted, it is the state’s or authorized tribe’s responsibility to determine how best to achieve the 

applicable designated use. If the commenter is also commenting that the HAU should not apply where 

the state or authorized tribe is removing or revising an agricultural designated use, EPA clarifies that the 

definition of HAU in the final rule specifies that the HAU is the “modified aquatic life, wildlife, or 

recreation use that is both closest to the uses specified in section 101(a)(2) of the Act and attainable....” 

(emphasis added). Furthermore, states and authorized tribes are only required to adopt the HAU when 

they conduct a UAA as specified in section 131.10(j). EPA recognizes that there may be instances where 

a state or authorized tribe removes the designated use, altogether, and in the same action adopts 

another designated use in a different broad use category (e.g., agricultural use). It may appear as though 

the state or authorized tribe intends the newly adopted use to be the HAU, when in fact this is a 

separate state or authorized tribal decision in the same rulemaking. For additional discussion on this 

topic, see response essays 5.g and 5.h.

EPA disagrees with the comment that the preamble to the proposed rule was unclear in terms of the 

problem the proposed amendments related to adopting the HAU were intended to address. The 

commenter only provided a comment that the commenter disagreed with any suggestion that states are 

“downgrading waters to avoid having to develop TMDLs.” EPA provided its rationale for the revisions in 

the preamble to the proposed rule (78 FR 54523-54525, September 4, 2013), and its rationale does not 

include the one that the commenter addresses. Please also see the preamble to the final rule for 

discussion on EPA’s rationale for the HAU requirement.

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EPA received a comment that said “The Proposed Rule should be revised to clarify that states are only 

required to apply a HAU for the purpose of determining whether some sub-category of aquatic or 

recreational use may be adopted in those circumstances when a State is using a UAA to remove an 

aquatic or recreational use.” EPA wishes to clarify here that the language in section 131.10(g) of the final 

rule clearly specifies that the HAU is required when states and authorized tribes adopt a new or revised 

WQS based on a required UAA per section 131.10(j). Section 131.10(j) requires a UAA in scenarios where 

a state or authorized tribe is removing a use specified in section 101(a)(2) of the CWA or a sub-category 

of such use, as well as where a state or authorized tribe is designating a use for the first time that does 

not include the uses specified in section 101(a)(2) of the Act. If a state or authorized tribe is designating a 

use specified in section 101(a)(2) of the Act for the first time, a UAA is not required and therefore the 

HAU requirement does not apply. EPA’s preamble to the proposed rule and final rule also makes clear 

what EPA means by “uses specified in section 101(a)(2) of the Act” or “subcategories of uses specified in 

section 101(a)(2) of the Act.” Specifically, EPA’s final rule preamble says “For the purposes of today’s 

final rule, the phrase “uses specified in section 101(a)(2) of the Act” refers to uses that provide for the 

protection and propagation of fish,

2 shellfish, and wildlife, and recreation in and on the water, as well as 

for the protection of human health when consuming fish, shellfish, and other aquatic life. A “subcategory of a use specified in section 101(a)(2) of the Act” refers to any use that reflects the subdivision 

of uses specified in section 101(a)(2) of the Act into smaller, more homogenous groups for the purposes

of reducing variability within the group.”3

With regard to the comment requesting more clarity on how the HAU should be determined for 

ephemeral streams, EPA provides an example in the preamble to the final rule that is specific to effluent 

dependent waters. With regard to the comment requesting more clarity on the factors that should be 

considered in determining whether aquatic life support can be reasonably attained in intermittent 

streams, EPA did not propose or finalize any changes to the factors specified in section 131.10(g); 

therefore, this comment is outside the scope of this rulemaking. However, EPA notes that the final 

regulation does not prohibit states and authorized tribes from removing a designated use specified in 

CWA section 101(a)(2) or a subcategory of such a use, altogether, where demonstrated to be 

unattainable. For example, a state or authorized tribe may remove an aquatic life use if it can 

demonstrate through a UAA that no aquatic life use or subcategory of aquatic life use is attainable. For 

purposes of this regulation, states and authorized tribes either consider there to be no aquatic life HAU 

or that the HAU is “no aquatic life use.” Again, EPA expects such situations to be rare; however, to clarify 

that this outcome is possible, EPA adds the following to the definition of HAU in the final rule at section

131.3(m): “There is no highest attainable use where the State [or authorized tribe] demonstrates the 

relevant use specified in section 101(a)(2) of the Act and subcategories of such a use are not attainable.”

2 To achieve the CWA’s goal of “wherever attainable...protection and propagation of fish...,” all aquatic life, 

including aquatic invertebrates, must be protected because they are a critical component of the food web. 3 A sub-category of a use specified in section 101(a)(2) of the Act is not necessarily less protective than a use 

specified in section 101(a)(2) of the Act. For example, a cold water aquatic life use is considered a use subcategory, but provides “for the protection and propagation of fish, shellfish and wildlife,” consistent with CWA 

section 101(a)(2). On the other hand, a secondary contact recreation use (i.e., a use, such as wading or boating, 

where there is a low likelihood of full body immersion in water or incidental ingestion of water) is considered a use 

sub-category, but does not provide “for recreation in and on the water,” consistent with CWA section 101(a)(2).

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With regard to the comment that adopting the HAU for ephemeral and intermittent headwater habitat 

streams will be problematic as naturally expected populations aren’t easily defined, and vary widely 

among seemingly comparable sites, EPA clarifies that how detailed a state or authorized tribe wishes to 

be with its designated uses is solely at the discretion of the state or authorized tribe, as long as the use 

reflects the HAU consistent with CWA requirements and EPA’s implementing regulation. 

With regard to comments that EPA’s regulatory revisions prohibit the ability of states and authorized 

tribes to consider “use and value” when designating and managing their waters, please see response 

essays 5.k. and 5.i.

D. Use Attainability Analyses

EPA received comments that suggested EPA approved UAAs. EPA clarifies that it does not approve or 

disapprove UAAs, but rather evaluates the UAAs and approves or disapproves revisions to a state’s or 

authorized tribe’s designated uses based on its evaluation. EPA also notes it does not and cannot force a 

state or authorized tribe to downgrade its designated uses. Such decisions are at the discretion of the 

state or authorized tribe. EPA also cannot force a state or authorized tribe to conduct a UAA if it is not 

required by section 131.10(j).

EPA disagrees that the final rule is inconsistent with its March 2006 memorandum issued by Ephraim 

King on “Improving the Effectiveness of the Use Attainability Analysis (UAA) Process.” For additional 

discussion on this topic, see response essay 5.b.

EPA disagrees with the comment that a UAA based on section 131.10(g)(3) (“human caused conditions 

or sources of pollution prevent the attainment of the use and cannot be remedied or would cause more 

environmental damage to correct than to leave in place...”) could prevent the HAU from being identified 

and adopted, due to the cost or consequences to an existing point source. If a state or authorized tribe 

removes a use specified in section 101(a)(2) of the Act based on section 131.10(g)(3), it would still be 

required to adopt the highest degree of the use that is attainable in light of the human caused 

conditions or sources of pollution. In addition, cost is not considered under section 131.10(g)(3).

EPA’s requirement for the HAU remains consistent with the intent of the 1983 preamble to the final rule 

which said “A State need only conduct a use attainability once for a given water body and set of uses.”

EPA maintains this policy statement, but it is important to recognize that if a state or authorized tribe 

revises the applicable designated uses, then it is a new “set of uses” and a UAA may indeed be required 

per section 131.10(j).

E. Burden

EPA disagrees with the comment that the UAA process is overly burdensome and complex. EPA has 

approved use changes supported by UAAs that range from simple to complex. For additional discussion 

on this topic, see response essay 5.j.

EPA received many comments suggesting that EPA underestimated the burden and cost of the proposed 

rule. States specifically requested to meet with EPA to provide additional information for EPA to 

consider. EPA engaged the states, as requested, and incorporated the information provided into its final 

EA. EPA’s EA and an explanation for how EPA derived its cost and burden estimates are documented in 

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the Economic Analysis for the Water Quality Standards Regulatory Revisions (Final Rule) and can be 

found in the docket for this rule. For additional discussion on burden, see response essay 12.a.

F. Other

EPA disagrees with the comment that the proposed rule does not alleviate concerns related to the 

identification and implementation of the HAU that were raised during the August 2010 public listening

sessions. The goal of these informal listening sessions was to inform the public about the rulemaking 

and receive input on changes EPA was considering at that time, not to accept formal public comments 

on the proposed rule. Participants at the public listening sessions were reminded that any comments or 

concerns expressed during the sessions needed to be resubmitted to EPA during the public comment 

period in order to be formally considered as part of the rulemaking effort. To the extent comments 

raised in the August 2010 public listening session were also identified in formal comments, EPA has 

addressed them as part of these response to comments.

One commenter provided a state-specific example of how agency approval of a UAA would be subject to 

third party legal challenges at both the state and federal levels. This comment is outside the scope of 

this rulemaking.

With regard to the comment that the choice of a HAU should involve identifying the current and 

expected condition for a water body, yet by failing to mention the role of existing uses and the water 

quality necessary to support them, EPA is implying that a water body degraded since 1975 can be 

evaluated in its present state without regards to its 40 year old history, EPA disagrees. States and 

authorized tribes may not remove designated uses if they are existing uses, per section 131.10(h)(1), 

and the final rule does not in any way modify or revise this requirement. Therefore, if a state or 

authorized tribe is adopting a HAU in lieu of an unattainable use, it must have already considered 

whether removal of the unattainable use would remove an existing use and already demonstrated that 

it had a basis to remove protection for the unattainable use. 

EPA disagrees with the comment that the final rule is requiring states and authorized tribes to review 

HAUs during triennial reviews. EPA recommends states and authorized tribes consider the HAU during a 

triennial review. Should they decide that – as a result of their review – a revision to WQS is necessary

such that a UAA is required per section 131.10(j), the adoption of the HAU would also be required per 

the final rule language at section 131.10(g). EPA also disagrees with the comment that the use of the 

word “should” rather than “must” in the preamble to the proposed rule undermines the intent of the 

proposed rule (i.e., “...EPA recommends that states and tribes consider the HAU during a triennial 

review. If new information becomes available during a triennial review to indicate that the uses 

specified in 101(a)(2) are attainable, then §131.20(a) requires that “the State shall revise its standards 

accordingly.” If new information becomes available during a triennial review to indicate that a use 

higher than what is currently designated is attainable but the uses specified in section 101(a)(2) of the 

Act are still unattainable, states and tribes should revise their WQS to reflect the HAU...” (78 FR 54524, 

September 4, 2013)). EPA considered requiring states and authorized tribes to always adopt the HAU in 

section 131.20(a) as part of their triennial review process; however, in an effort to limit the burden on 

states and authorized tribes EPA instead limited the HAU requirement to only instances where a UAA is 

required per section 131.10(j). EPA does not believe such a provision is counter to the goals of the CWA 

because EPA’s regulation at section 131.10(i) also requires that “where existing water quality standards 

specify designated uses less than those which are presently being attained, the State shall revise its 

standards to reflect the uses actually being attained.” Title 40 of the Code of Federal Regulations (CFR) 

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section 131.20(a) clearly requires states and authorized tribes to revise their WQS in instances where 

new information indicates that uses specified in section 101(a)(2) of the Act are attainable; therefore, 

EPA does not view the word “should” as being in conflict.

EPA disagrees with the comment that the requirement to adopt the HAU could have the unintended 

consequence of requiring states and authorized tribes to adopt drinking water standards (or to justify 

not adopting drinking water standards) every time a state or authorized tribe revises its WQS. The 

requirement to adopt the HAU only applies to the uses specified in section 101(a)(2) of the Act, or subcategories of such uses. EPA refers commenters to the definition of HAU at section 131.3(m) of the final 

rule. A public water supply use is a non 101(a)(2) use. Commenter is referred to section 131.10(g) and (j) 

of the final rule, which limits the HAU requirement to instances when a UAA is required in section

131.10(j), and section 131.3(q) of the final rule, which defines a non 101(a)(2) use.

One commenter requested that EPA clarify the following language from the proposal: “where uses 

specified in section 101(a)(2) are unattainable, it is important that states and authorized tribes still strive 

to attain uses that continue to serve the purposes of the Act and also enhance the quality of the water.”

As part of the UAA process, a state or authorized tribe may be able to demonstrate that a particular 

class of aquatic life is not attainable; however, if some less sensitive aquatic organisms are able to 

survive at the site under current or attainable future conditions, the goals of the CWA are not served by 

simply removing the aquatic life use designation and applicable criteria without determining where 

there is some alternate 101(a)(2) use or subcategory of such a use that is feasible to attain.

One commenter stated that the language in the final rule expands EPA’s CWA authority to regulate NPS

pollution through evaluation and use of BMPs. EPA’s requirement at section 131.10(d) existed prior to 

this action to revise EPA’s rule, and EPA did not propose any revisions to this provision or how NPS BMPs 

relate to the designation of uses. Therefore, this comment is outside the scope of this rulemaking. 

One commenter suggested that EPA clarify that the impacts of combined sewer overflows (CSOs) can be 

stopped and mitigated; for example, by separating stormwater and sewer lines. This comment is outside 

the scope of this rulemaking.

EPA agrees with the comment that states and authorized tribes should have the authority to determine 

and assign appropriate uses and accompanying WQS, and not the EPA. States and authorized tribes 

continue to have the primary responsibility for establishing categories of designated uses, assigning 

those uses to specific water bodies within their jurisdiction, and determining how to best satisfy the 

requirements of the regulation.

With regard to the comment that EPA should clarify when uses associated with human health criteria 

are considered 101(a)(2) uses, EPA interprets CWA section 101(a)(2) to include the protection of human 

health when consuming fish and shellfish. This is consistent with the language, purposes, and structure 

of the CWA. CWA section 303(c)(2)(A) requires that WQS protect public health and CWA section 

101(a)(2) establishes the broad goal of “...protection and propagation of fish, shellfish, and wildlife and 

provides for recreation in and on the water...” Given the breadth of this goal, EPA has implemented 

section 101(a)(2) to refer not only to protecting water quality so the fish and shellfish thrive, but also to 

protect them as a food source. Thus, to be consistent with section 101(a)(2), the applicable designated 

uses must not only protect the aquatic organisms themselves, but also protect consumers of the aquatic 

organisms from the accumulation of pollutants to levels that result in unacceptable risk to human 

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health. States and authorized tribes should consider local consumption practices when determining the 

appropriate consumption rate that is used to meet that level of protection.

EPA has reflected this interpretation in several past actions and statements. In the National Toxics Rule, 

40 CFR section 131.32, EPA promulgated numeric human health criteria for toxic pollutants in water 

bodies designated for an aquatic life use with a potential consumption exposure route for any state or 

tribe that did not have such criteria. EPA promulgated these criteria to protect human health if humans 

might consume any fish or shellfish in these waters. EPA also said that if a state or tribe wishes to 

demonstrate that a waterbody segment designated for aquatic life use does not support fish or shellfish 

consumption and does not require human health criteria, then the state or tribe must complete a UAA. 

This UAA must demonstrate why it is infeasible to attain a use that provides for fish and shellfish 

consumption by humans consistent with EPA’s regulations at 40 CFR section 131.10.4 EPA has described 

this position in various public documents (please see EPA’s October 2000 memo on fish and shellfish 

advisories and 303(d) lists (WQSP-00-03, October 24, 2000, 

http://www.epa.gov/scitech/swguidance/standards/upload/2000_10_31_standards_shellfish.pdf), 

EPA’s October 2000 Human Health Methodology (EPA-822-B-00-004, and

http://www.epa.gov/waterscience/criteria/humanhealth/method/complete.pdf, pages 4-2, 4-3)).

4 57 FR 60848, 60859-60 (December 22, 1992).

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Essay 5.f.ii – Designated Uses: Criteria for Protecting HAU 

The final rule language at section 131.10(g) does not include the phrase “and the criteria to protect that 

use” that was included in the proposed rule language. The U.S. Environmental Protection Agency’s 

(EPA’s) position is that sections 131.5(a)(2), 131.6(c) and 131.11(a) already explicitly require states and 

authorized tribes to adopt water quality criteria that protect designated uses; therefore, it is 

unnecessary to repeat this requirement in the final rule language at section 131.10(g). EPA removed this 

phrase because some commenters were concerned that EPA’s proposal meant that states and 

authorized tribes must adopt the highest attainable criteria. EPA’s final rule is clear that states and 

authorized tribes must adopt the highest attainable use (HAU) and the criteria protects this use. Please 

see below for additional discussion.

EPA acknowledges and appreciates the comment agreeing that it is necessary and appropriate for states

and authorized tribes to adopt criteria to protect the HAU, and stating that a specific state is allotting 

time in its work plan for this effort.

With regard to comments that states should set criteria to be protective of uses and not necessarily the 

HAU, EPA agrees in part and disagrees in part. EPA agrees that the Clean Water Act (CWA) and the water 

quality standards (WQS) regulation at sections 131.5(a)(2), 131.6(c) and 131.11(a) explicitly require 

states and authorized tribes to adopt criteria to protect designated uses. However EPA disagrees that 

criteria should not be set to protect the HAU. The HAU, once adopted, is the applicable designated use 

for which the CWA and regulation requires states and authorized tribes to adopt protective criteria. EPA 

will evaluate each submission independently in light of the information and analysis submitted by the 

state/authorized tribe to determine whether the revision is consistent with the CWA and regulation. 

EPA agrees with comments that developing water quality criteria to protect the HAU may be a resourceintensive undertaking, depending on a state’s or authorized tribe’s specific circumstances and available 

resources. EPA notes, however, that in order to meet the requirement of the CWA and implementing 

regulations, states and authorized tribes are not required to adopt modified criteria for every pollutant, 

if only one pollutant is affecting the attainability of the use. Rather, a state or authorized tribe could 

adopt a new sub-category of a use that uniquely recognizes the limiting condition for a specific water 

body (e.g., aquatic life limited by naturally high levels of copper). In this situation, a state or authorized 

tribe could adopt the highest attainable criterion for copper, and leave the criteria for all other 

pollutants unchanged.

With regard to comments that the HAU approach will be limiting to states and their ability to run their 

WQS programs, EPA is not providing a substantive response. The commenter made the statement but

did not explain why the HAU approach would limit the ability to run their WQS programs. 

EPA disagrees with comments that implementing the HAU will lead to the adoption of numerous new 

sub-categories and associated criteria. For additional discussion on this topic, see response essay 5.e.

One commenter requested clarity on whether a state-specific situation regarding combined sewer 

overflow (CSO) related use designations that lack applicable numeric criteria are consistent with the 

final rule. This comment is outside the scope of the rulemaking; therefore, EPA is not providing a 

substantive response. 

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Chapter 3 – Response Essays 5.g – DU – Clarify 131.10 g, j, k 

Essay 5.g – Designated Uses: Section Clarifications when a UAA is 

Required (131.10(g), (j) and (k)) 

A. General Support

The U.S. Environmental Protection Agency (EPA) acknowledges the general support for the revisions 

clarifying sections 131.10(g), (j) and (k), as well as those states and/or authorized tribes that noted they 

would not be affected by the revisions. Specifically, EPA appreciates the support expressed by numerous 

commenters for the modifications to section 131.10(g) clarifying that the factors listed in (g) are only 

required when a use attainability analysis (UAA) is required as specified in section 131.10(j); the 

modifications to 131.10(g) regarding the highest attainable use (HAU); the modifications to 

section 131.10(j) clarifying when a UAA is required; and the modifications to section 131.10(k) clarifying 

that a UAA is not needed to remove a non-101(a)(2) use.

B. General Opposition

EPA disagrees with comments that there is no basis for revising the designated use and use attainability 

provisions, and that such revisions will place an unreasonable burden on states and authorized tribes. 

EPA provided its general rationale for the revisions in the preamble to the proposed rule (78 FR 54523 - 

54525, September 4, 2013). As discussed in the preamble to the final rule, the narrowing of the UAA 

requirement to just instances when required in section 131.10(j) reduces the burden on states and 

authorized tribes from conducting a UAA for all designated use removals, EPA’s prior view of the 

regulations. Also, as explained in EPA’s preamble the final rule, the HAU requirement is the resulting 

attainable use after determining what is not attainable based on the evaluation of the factors and other 

information used to evaluate attainability. EPA’s intent with this requirement is to mitigate burden to 

the extent possible, because the HAU determination would be made using the same information already 

required by the regulations. In addition, the regulation provides states and authorized tribes with 

discretion on how to articulate the HAU in its water quality standards (WQS) as long as their approach is 

protective of the HAU and is consistent with the Clean Water Act (CWA) requirements and EPA’s 

regulation. See section II.B of the preamble to the final rule. For further discussion on the burdens and 

costs associated with the final rule, please see response essay 12.c. See also the economic analysis (EA) 

for the final rule in the docket for this rulemaking.

C. Comments on Section 131.10(g) 

The final rule makes two significant changes to section 131.10(g) consistent with EPA’s proposal. First, 

the regulation includes an explicit reference to section 131.10(j) that clearly identifies the specific 

circumstances where a state or authorized tribe must conduct a UAA that demonstrates that attaining 

the use is not feasible because of one of the six regulatory factors. Second, the rule establishes that if 

the state or authorized tribe adopts a new WQS or revised WQS based on a required UAA, it must adopt 

the HAU in place of the previous WQS. See essays 5.f., 5.f.i, and 5.f.ii for additional discussion on HAU.

Today’s final rule at section 131.10(g) differs from the proposed rule in two ways. First, the final rule 

contains editorial changes to section 131.10(g) as compared to the proposed rule. These editorial 

changes ensure that EPA is not unintentionally making substantive changes to its existing use 

requirements at sections 131.10(g) and (h)(1), and that the rule language separates the acts of 

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designating and removing uses, as they relate to existing uses. Specifically, the regulation prior to the 

proposed revisions required that, when removing a designated use, states or authorized tribes first 

consider whether the use to be removed is an existing use and, if so, the use could not be removed: 

“States may remove a designated use which is not an existing use...” However, EPA proposed changes to 

section 131.10(g) that may be read to unintentionally prohibit states and authorized tribes from 

removing a designated use if it removes protection for any existing use: “Pursuant to § 131.10(j), States 

may designate or remove a use or sub-category of a use as long as the action does not remove 

protection for an existing use and the State can demonstrate that attaining the use is not feasible 

because of one of the six factors in this paragraph....” (emphasis added). Prohibiting removal of a 

designated use if the action removes protection for any existing use was not EPA’s intent in the 

proposed rule. Instead, EPA intended to only prohibit removal of a designated use if that use is also the 

existing use. In addition, to better align section 131.10(g) and section 131.10(j), the final rule 

incorporates editorial changes in section 131.10(g) and now reads as follows: “States may designate a 

use, or remove a use that is not an existing use, if the State conducts a use attainability analysis....” Prior 

to today’s rule, section 131.10(g) spoke only to removing a designated use whereas section 131.10(j)(1),

speaks to the requirement to conduct a UAA when designating uses for the first time that do not include 

the uses specified in section 101(a)(2) of the Act. Today’s editorial revisions make both provisions 

parallel and consistent. 

Second, the final rule differs from the proposed rule in that EPA deleted the last sentence in the 

proposed revisions to section 131.10(g): “To meet this requirement, States may, at their discretion, 

utilize their current use categories or subcategories, develop new use categories or subcategories, or 

adopt another use which may include a location specific use.” A number of commenters expressed 

concern that this sentence implied that states and authorized tribes were limited to these three specific 

options for articulating the HAU, and would be unable to articulate the HAU in a different way. This was 

not EPA’s intent; rather, EPA’s intent is to provide states and authorized tribes with discretion to pick an 

option for articulating the HAU that works best for them, provided that the selected option still meets 

the HAU requirement. Related to similar comments concerning state discretion, EPA made two related

revisions. EPA revised section 131.10(g) to include an explicit reference to the definition of HAU at 

131.3(m). EPA also revised the definition to add specificity and clarify that the HAU is the use that results 

from the [state’s or authorized tribe’s] process of determining what is not attainable (see response 

essay 5.e for discussion on the definition of HAU). For additional discussion regarding the adoption of 

the HAU and the available discretion to states and authorized tribes, please see response essay 5.f.i.

EPA disagrees with the comment that the proposed rule language at section 131.10(g) should be 

restructured using separate subsections to describe the addition and removal of designated uses. The 

commenter did not provide any discussion on why such restructuring should be done. EPA refers the 

commenter to the final rule language at section 131.10(g), as EPA has made a number of edits for clarity.

EPA disagrees with the comment that the addition of the phrase “States may designate a use....” in 

section 131.10(g) of the final rule creates confusion and gives additional oversight to EPA. In addition, by 

referencing section 131.10(j) in section 131.10(g), EPA’s intent is to provide clarity for the specific 

circumstances a state or authorized tribe must conduct a UAA and demonstrate that the use is not 

feasible to attain because of one of the attainability factors at section 131.10(g) before designating, 

revising, or removing certain uses.

EPA disagrees with the suggested revision to section 131.10(g) that provides “States may adopt new or 

revised designated uses that do not protect for the uses specified in section 101(a)(2) of the Act, only 

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when consistent with the other provisions of § 131.10....” EPA’s intent with the specific language in the 

final rule in section 131.10(g) is to clearly link the requirements in section 131.10(g) to the situations 

when a UAA is required by section 131.10(j). The language suggested by the commenter could be read 

to mean that the requirements of section 131.10(g) is independently applicable and thus a UAA using 

the factors listed at section 131.10(g) and the requirement to adopt the HAU is required when a state or 

authorized tribe adopts a new or revised non-101(a)(2) use since such uses “do not protect for the uses 

specified in section 101(a)(2) of the Act.” EPA does not want to risk causing such uncertainty. EPA’s final 

rule revises section 131.10(j) and section 131.10(k) to clearly reflect what is required to adopt new or 

revised designated uses, depending on what is being adopted, removed or revised and it is thus 

unnecessary to add anything more to section 131.10(g).

EPA disagrees and agrees in part with comments that identification of the HAU should be an option left 

to a state’s or authorized tribe’s discretion. EPA disagrees with comments that states and authorized 

tribes should not be required to adopt the HAU. If leaving identification of the HAU to the discretion of 

the state or authorized tribe means that EPA would have to defer to a state or authorized tribe’s 

decision whether to identify a HAU, such a provision would not be a requirement at all and would not 

further the purposes of the Act efficiently, if at all. Allowing states and authorized tribes full discretion to 

determine whether to identify the HAU could result in a situation where the state or authorized tribe 

chooses not to adopt an HAU where there is indeed a higher use attainable because their current use 

structure does not accommodate this use. Such a result would not meet the purposes of the CWA as 

implemented by the final rule. EPA’s authority under the CWA is to promulgate regulations and oversee 

state and authorized tribal actions to ensure that the requirements of the CWA are met. That said, EPA 

agrees that states and authorized tribes have discretion in how they choose to articulate their HAU. 

EPA’s preamble to the final rule provides some examples that states and authorized tribes may use but 

explicitly explains: “States and authorized tribes are not limited by the examples described in this 

section and can choose a different approach that aligns with their specific needs, as long as their 

preferred approach is protective of the HAU and is consistent with the CWA and § 131.10.” See section 

II.B of the preamble to the final rule. EPA disagrees with the comment that states and authorized tribes 

should not be required to adopt the HAU because it would be inconsistent with EPA’s implementation 

and interpretation of the CWA. EPA’s preambles to the proposed rule and the final rule provide

explanations for the HAU requirement, when it applies, and why such a requirement is reasonable,

consistent with the objectives of the CWA, and serves the purposes of the Act. Please see also response 

essays 5.f.i and 5.k. regarding the HAU. Response essay 5.f.i. specifically discusses articulating the HAU 

and state/authorized tribal discretion. 

Comments stated that EPA should clarify that the HAU requirement is not required outside of a UAA. 

EPA’s final rule makes clear at section 131.10(g) that the requirement to adopt the HAU is limited to 

instances when a UAA is required per section 131.10(j). EPA disagrees with the comment that incorrectly 

states that a UAA and the associated HAU are required for changes to 303(c)(2)(A) uses. EPA’s 

clarifications in the final rule to section 131.10(g), section 131.10(j, and section 131.10(k) make clear 

when a UAA is required and thus, when adoption of the HAU is required.

EPA acknowledges that some commenters expressed support for the modification to section 131.10(g) 

that provided states and authorized tribes with discretion to utilize their current use categories or 

subcategories, develop new use categories or subcategories, or adopt another use (including a locationspecific use) when adopting the HAU. Other commenters suggested modifications to this proposed 

language, such as clarifying that current use categories/subcategories may only be used if they 

sufficiently identify and protect the HAU. EPA notes that this text no longer appears in the final rule in

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section 131.10(g), as some commenters expressed concern that this sentence implied that states and 

authorized tribes were limited to only these examples and that EPA should be clear these approaches 

are non-exclusive. It was not EPA’s intent to make these approaches exclusive. States and authorized 

tribes may choose different approaches for articulating the HAU that align with their specific needs, as 

long as the approaches are consistent with the CWA and section 131.10. In the preamble to the final 

rule, EPA provides a fourth option for states and authorized tribes to consider when determining how to 

articulate the HAU, and, as discussed earlier, clearly provides that states and authorized tribes are not 

limited to these examples as long as whatever approach they take protects the HAU and is consistent 

with the CWA and section 131.10. For additional discussion see Essay 5.f.i.

EPA disagrees with several commenters who suggested modifying section 131.10(g) to provide that 

when adopting new or revised WQS based on a UAA, a state or authorized tribe should ensure such 

standards include or protect (all) attainable uses, rather than adopting the HAU. EPA considered 

finalizing this modification to section 131.10(g); however, EPA recognized that saying “all attainable 

uses” could imply that states and authorized tribes must adopt more than one use to replace the 

unattainable designated use, and it could further the misconception that when conducting a UAA for 

one broad use category (e.g., aquatic life), states and authorized tribes must consider adopting 

attainable uses in other broad use categories (e.g., public water supply, recreation, agricultural uses). 

Rather, to continue to strive toward restoring and maintaining the chemical, physical, and biological 

integrity of the nation’s waters and to enhance the quality of the water, the state or authorized tribe

must adopt the HAU that is closest to the use(s) specified in CWA section 101(a)(2) that is (are) the 

subject of the use removal. Further, the intent of the regulation is to focus the states, authorized tribes, 

and the public on adequately determining what the HAU is for the applicable use category being 

removed (e.g., if not full protection and propagation of fish, shellfish, and wildlife, then the HAU related 

to full protection and propagation of fish, shellfish, and wildlife). 

EPA also received several comments related to the attainability factors specified in section 131.10(g). 

Specifically, some commenters suggested that the factors at section 131.10(g)(3), (g)(5), and (g)(6) 

should not be allowed (or should be refined to avoid exploitation) when conducting a UAA, or that EPA 

should differentiate between the factors that are naturally occurring and those that are 

anthropogenically induced. Other commenters stated that the section 131.10(g) factors do not allow 

sufficient flexibility to change designated uses and/or are “difficult to prove.” The final rule does not 

modify the section 131.10(g) factors in any way nor did EPA request comments on such revisions or the 

factors in general with respect to designated uses. Therefore, such comments are outside the scope of 

this rulemaking; however, EPA has provided guidance on these and related issues, and commenters may 

find it helpful to review EPA’s “UAAs and Other Tools for Managing Designated Uses”1 (March 2006) as 

well as EPA’s “Interim Economic Guidance for Water Quality Standards”2 (March 1995) for assistance in 

working with section 131.10(g)(6). Additionally, EPA intends to provide additional guidance on uses in 

the future and will consider addressing the section 131.10(g) factors further at that time.

EPA also acknowledges a commenter who suggested revising section 131.10(g) to clarify that each of the 

six factors are independent of each other, and factor 6 is not a precondition for any of the other factors. 

As noted previously, the final rule does not modify the section 131.10(g) factors in any way and, 

therefore, such a comment is outside the scope of this rulemaking. However, EPA notes for the 

commenter that the regulatory language at section 131.10(g) clearly states that only “one of the six 

 

1 http://water.epa.gov/scitech/swguidance/standards/upload/2007_08_08_standards_uses_uaa_cs-all.pdf 2 http://water.epa.gov/scitech/swguidance/standards/upload/2007_06_18_standards_econworkbook_complete.pdf

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factors” is required when demonstrating that attaining a use is not feasible. This is consistent with EPA’s 

previously existing regulation at 131.10(g) that included an “or” in between each of the factors, making 

clear that each factor is independent of one another.

EPA disagrees with the commenter who suggested modifying the language in section 131.10(g) to clarify 

that a UAA is not required when revising a section 101(a)(2) designated use to more accurately reflect 

the use that is attainable (e.g., a sub-category of such a use that is still protective of the uses specified in 

section 101(a)(2)). The 1983 regulations provided a framework where 131.10(g) describes the factors 

that can be used to evaluate attainability when conducting a UAA, while section 131.10(j) and (k) 

address the circumstances where a UAA is or is not required. Today’s rule maintains this structure and it 

would be inappropriate to specify one specific circumstance where a UAA is not required in section 

131.10(g) if all other scenarios are addressed in section 131.10(k). The scenario specifically identified by 

the commenter is addressed in the final rule at section 131.10(k)(2) which says that a UAA is not 

required if the state or authorized tribe designates a subcategory of a use specified in section 101(a)(2) 

of the Act that requires criteria at least as stringent as previously applicable. 

Regarding the comment that EPA is more readily allowing use downgrades by narrowing when a UAA is 

required, see response essay 5.h. EPA disagrees with the commenter who stated that EPA did not 

adequately explain why it is taking a position different than the one taken in the 1998 Advance Notice of 

Proposed Rulemaking (ANPRM). In the preamble to the proposed rule, EPA recognized its previous 

interpretation in the 1998 ANPRM, but clearly laid out its legal analysis of the CWA and the regulations 

to explain why EPA now believes that the better interpretation is that a UAA is only required when 

removing or revising a use specified in CWA section 101(a)(2) or a subcategory of such a use. In addition, 

it is important to note that although a state or authorized tribe is not required to conduct a UAA when 

removing a use not specified in CWA section 101(a)(2), this does not mean that there is no evaluation 

done to justify removal. EPA’s final rule further revises section 131.10(k) to be clear what is required 

when removing a non-101(a)(2) use. Related to this, EPA’s preamble provides guidance on 

considerations for states and authorized tribes when taking into account the “use and value” for a 

water. In addition, EPA intends to provide additional guidance on uses after the final rule is published.

Please also see response 5.h. for additional discussion on non-101(a)(2) uses.

D. Comments on Section 131.10(j) 

EPA disagrees with the comment that the “rebuttable presumption” is not supported by the statute and, 

therefore, section 131.10(j)(1) should be deleted. For further discussion on the rebuttable presumption 

concept, please see response essay 5.i.

EPA notes that the most substantive change it made to section 131.10(j) is to make an explicit link to 

section 131.10(g) to make clear that these provisions are linked. EPA acknowledges that it made changes 

to the language in section 131.10(j)(1) and (2) but as discussed below, such changes were refinements

and are consistent with the 1983 requirements and EPA’s implementation of those requirements. EPA’s 

prior existing regulation at 131.10(j) provides that “A State must conduct a use attainability analysis as 

described in § 131.3(g) whenever: (1) The State designates or has designated uses that do not include 

the uses specified in section 101(a)(2) of the Act, or (2) The State wishes to remove a designated use 

that is specified in section 101(a)(2) of the Act or to adopt subcategories of uses specified in section 

101(a)(2) of the Act which require less stringent criteria.” In discussing section 131.10(j)(1) and (2), the 

1983 final rule preamble explained that, “[i]n the final rule, EPA is requiring that States conduct and 

submit to EPA a use attainability analysis if the State (a) is designating uses for the water body such that 

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the water body will not have all uses which are included in Section 101(a)(2) of the Act, (b) maintaining 

uses for the water body which do not include all of the uses in Section 101(a)(2) of the Act , (c) removing 

a use included in Section 101(a)(2) of the Act or (d) modifying a use included in Section 101(a)(2) of the 

Act to require less stringent criteria.” Water Quality Standards Regulations, 48 Fed. Reg. 51400, 51401

(November 8, 1983). 

In the final rule, EPA is making limited wording changes to reflect EPA’s longstanding position that under 

the 1983 regulations a UAA is required when a state or authorized tribe designates uses for a water 

body for the first time where those uses do not include the uses specified in section 101(a)(2) of the Act 

– that is, when a state or authorized tribes designates non-101(a)(2) uses or uses that do not reflect the 

uses specified in CWA 101(a)(2) (e.g., subcategories of the uses specified in 101(a)(2) of the Act that do 

not represent the “full” 101(a)(2) goal uses) for a water body that previously had no designated uses 

assigned (sometimes referred to as “unclassified waters”). This reading is well supported by EPA’s 1983 

preamble discussed above that makes clear that 131.10(j)(2) applied to instances where the state or 

authorized tribe was removing or revising previously adopted designated uses and therefore it most 

logically follows that 131.10(j)(1) is speaking to the first instance where the state or authorized tribe 

“designates” uses for a waterbody. Therefore, EPA revised the language in section 131.10(j)(1) from the 

proposal to final to make clear that the “first time” language applies to instances where the state or 

authorized tribe designates uses that do not reflect uses specified in section 101(a)(2) of the Act in this 

first instance.

EPA also made edits to the “has designated uses” that appear in EPA’s prior existing regulations in 

section 131.10(j)(1) to clarify what this language means. It is clear from the preamble to the 1983 final 

rule that the phrase “has designated uses” was meant to require a UAA when the state was 

“maintaining uses for a water body which did not include all of the uses in Section 101(a)(2) of the 

Act” or “to justify continuation of standards which do not include” such uses. (48 FR 51400-01, 

November 8, 1983). EPA’s position is that this regulation meant to capture instances where a state had 

previously designated uses prior to the 1983 regulation but had not conducted a UAA. EPA determined 

that these instances can still occur in present day. EPA’s current position is that the “has designated 

uses” language refers to instances where WQS are in effect for CWA purposes as determined by section 

131.21(c) or where a tribe may have designated waters prior to obtaining treatment in a manner similar 

to a state (TAS) and other applicable situations. Therefore, edited the language in the final rule to make 

clear that the “has designated uses” language is referring to “previously designated” uses. EPA changed 

the language from the proposal which included the phrase “has designated uses for the waterbody for 

the first time” to avoid any further confusion. For the reasons discussed above, EPA disagrees with the 

comment that EPA’s changes to section 131.10(j)(1) requires UAAs in cases where they were not 

previously required. The revisions EPA made in section 131.10(j)(1) were to clarify in regulation its long 

standing positions that are consistent with the 1983 regulations. 

EPA notes that it made two changes to the language in section 131.10(j)(2) that are consistent with 

EPA’s intent of the 1983 regulations. First, EPA finalized its proposal to make clear that a UAA is required 

when a state or authorized tribe is designating a subcategory of such a use “that requires less stringent 

criteria than previously applicable” (emphasis added). EPA added the language “than previously 

applicable” because without such language, there has been confusion regarding to what the criteria 

should be compared. As discussed above, the 1983 preamble explained that 131.10(j)(2) is intended to 

capture those situations when a state or authorized tribe is “modifying a use included in Section 

101(a)(2) of the Act to require less stringent criteria.” This makes clear that the 1983 regulation was 

intended to address situations when the state or authorized tribe was modifying an already applicable 

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designated use to adopt a subcategory that would requires less stringent criteria. This means that the 

regulation was speaking to instances were there previously applicable criteria in effect for CWA

purposes would serve as a means of comparison. Second, EPA also added additional language to 

131.10(j)(2) to make clear that the UAA requirement applies when the states or authorized tribes

“removes a sub-category of such a use.” Today’s final rule preamble further explains that “[a] subcategory of a use specified in section 101(a)(2) of the Act is not necessarily less protective than a use 

specified in section 101(a)(2) of the Act.” Today’s rule implements the intent of the 1983 regulation to 

require a UAA when a state or authorized tribe “modifies” a use “included in Section 101(a)(2)”, which 

would involve both removing a subcategory of a use specified in CWA 101(a)(2) and adopting a new 

subcategory of a use specified in CWA 101(a)(2) that require less stringent criteria. It is also consistent 

with the explanation in the 1983 final rule preamble that a state or authorized tribe is required to 

conduct and submit a UAA when “(b) maintaining uses for the water body which do not include all of the 

uses in Section 101(a)(2) of the Act”. Where a subcategory of use specified in section 101(a)(2) of the 

Act is less protective than a use specified in section 101(a)(2) of the Act, removing such a subcategory 

would result in “maintaining” uses that do not include all of the uses in section 101(a)(2) of the Act. For 

these reasons, these revisions are consistent with EPA’s intentions as described in the 1983 preamble.

EPA disagrees with comments that it is unnecessary to conduct a UAA to remove a sub-category of a use 

specified in section 101(a)(2) of the Act (e.g., secondary contact recreation or a limited aquatic life use). 

EPA’s intent, consistent with CWA sections 101(a)(2) and 303(c)(2), is to require states and authorized 

tribes to continue striving for the goals of the CWA wherever attainable (i.e., protection and propagation 

of fish, shellfish, and wildlife and recreation in and on the water) and ensure that such uses enhance the 

quality of the water. Any decision by a state or authorized tribe to depart from these goals (e.g., by 

removing a sub-category of a use specified in 101(a)(2), such as a secondary contact recreation use or a 

limited aquatic life use) should be a thoughtful, publicly transparent decision that is based on a 

structured scientific assessment of the factors affecting the attainment of the use. The final rule at 

section 131.10(j)(2) makes clear that a UAA is required even when adopting, removing or revising a 

subcategory of a use specified in CWA section 101(a)(2). EPA received comments that the CWA does not 

support the requirements in section 131.10(j) describing when a UAA is required. As discussed above 

EPA is only making clarifying changes to these provisions in the final rule. The provisions themselves 

continue to reflect the same substantive requirement that has been in place since at least 1983 and 

reflects EPA’s longstanding interpretation of the CWA. For more discussion on this topic, see essay 5.i 

regarding the “Rebuttable Presumption” concept. 

With regard to the comment that states should be able to establish refined uses when new or revised 

WQS are being considered for the first time, EPA does not understand the comment as written. 

Nonetheless, EPA clarifies that, per the requirements in section 131.10(j)(1), states and authorized tribes 

may designate a use for the first time that does not include the uses specified in section 101(a)(2) of the 

Act (i.e., a sub-category of such a use or a non-101(a)(2) use), provided that a UAA is conducted and 

demonstrates that the uses specified in section 101(a)(2) of the Act are not attainable and that the state 

or authorized tribe has adopted the HAU. 

EPA disagrees with comments that the language in section 131.10(j)(2) should be revised to require a 

UAA whenever a state “wishes to remove, revise, or modify” a designated use that is specified in section 

101(a)(2) of the Act or a subcategory of such a use. Revising or modifying a use specified in section 

101(a)(2) of the Act does not necessarily require a UAA; for example, a state or authorized tribe may 

modify a broad use designation such as an “aquatic life use” to more accurately describe the aquatic 

ecosystem expected in the water body (e.g., a “coldwater fishery”). Doing so provides a clearer 

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description of the management objectives for the water and may make the designated use more 

effective; however, the modified coldwater fishery use is still a use specified in section 101(a)(2) of the 

Act, and thus no UAA would be required. EPA’s regulation at section 131.10(j) and (k) also reflect that 

whether a UAA is required when “designating a sub-category” of a use specified in section 101(a)(2) 

depends upon whether the criteria would become more or less stringent than what were previously 

applicable. In other words, a UAA is not required when a state or authorized tribe is “upgrading” its

101(a)(2) designated use within the same broad use category to be more specific and require the same 

or more stringent criteria (e.g., the example above of revising “aquatic life use” to “coldwater fishery”

where the criteria would either stay the same or become more stringent). 

EPA disagrees with a commenter’s suggested revisions to section 131.10(j)(2) that remove references to 

the phrase “specified in section 101(a)(2) of the Act.” These revisions would effectively change the 

meaning of section 131.10(j)(2) to imply that a UAA is required when a state or authorized tribe removes 

any designated use or any use sub-category, including non-101(a)(2) uses. As explained above, this is not 

EPA’s intent, and thus EPA disagrees with the comment. EPA also disagrees with the commenter’s 

addition of the phrase “or to remove a use that may provide protections for an existing use” in 

section 131.10(j)(2) is necessary. The prohibition against removing uses that are existing uses is already 

clear in section 131.10(h)(1) and reiterated in section 131.10(g). 

With regard to the comment that the proposed rule, through revisions to sections 131.10(g) and (j), is 

requiring that a UAA address both CWA sections 101(a)(2) and 303(c)(2)(A), this is incorrect. The 

commenter misunderstood the proposal. The final rule revises sections 131.10(g) and (j) so that when 

the provisions are read together, it is clear that the factors at section 131.10(g) are only required to be 

considered when a state or authorized tribe conducts a UAA under section 131.10(j). EPA also disagrees 

with the comment that UAAs should not be limited to uses specified in CWA section 101(a)(2) and 

subcategories of such uses. For further discussion on this topic, see above and response essay 5.h. 

E. Comments on Section 131.10(k) 

EPA’s previously existing regulations at section 131.10(j) explained when a UAA is required and section 

131.10(k) explained when a UAA is not required. Today’s revisions accomplish these same purposes by 

making revisions to ensure that these provisions are inverses of each other to avoid any situations 

where there could be a conflict. See Water Quality Standards Regulations, 48 Fed. Reg. at 51404

(explaining that “In paragraph (j), EPA has defined that States must conduct a Use Attainability Analysis 

if designating uses not specified in Section 101(a)(2) of the Act, when removing a use specified in Section 

101(a)(2) or if modifying uses specified in Section 101(a)(2) by requiring less stringent criteria. Paragraph 

(k) clarifies that States are not required to conduct a Use Attainability Analysis when designating uses 

specified in Section 101(a)(2) of the Act”), see also Water Quality Standards Regulatory Clarification; 

Proposed Rule, 78 Fed. Reg. 51518, 54525 (September 4, 2013). Therefore, EPA’s final rule adds section

131.10(k)(1) and (k)(2) so that they are parallel provisions to section 131.10(j)(1) and (j)(2). Any other 

revisions to the language in section 131.10(k), including the addition of the “first time”, “has previously 

designated” and reference to previously applicable criteria are discussed above. EPA also added (k)(3), 

consistent with its revisions to section 131.10(g) and (k), that a UAA is not required for removals or 

revisions to non-101(a)(2) uses. To avoid any future confusion, EPA also added a reference to the 

requirements provided in section 131.10(a).

EPA’s 1983 regulations, specifically sections 131.10(j) and (k), interpret and implement the CWA through 

requirements that WQS protect the uses specified in CWA section 101(a)(2) unless states and authorized 

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tribes show those uses are unattainable through a UAA consistent with EPA’s regulation, effectively 

creating a rebuttable presumption of attainability. Although EPA made clarifying revisions to the 

language in sections 131.10(j) and (k) as discussed in this essay, the underlying requirement was not a 

subject of this rulemaking and remains unchanged by today’s rule because the edits do not change the 

fundamental requirement to do a UAA where the state’s or authorized tribe’s standards do not reflect

the uses specified in section 101(a)(2) of the Act or where a state or authorized tribe is removing or 

modifying such uses. In addition, EPA kept the same basic structure that section 131.10(j) speaks to 

when a UAA is required and section 131.10(k) speaks to when a UAA is not required. The most 

substantive changes EPA made to sections 131.10(j) and (k) are to make clear that UAAs are not 

required for non-101(a)(2) use removals, which leaves untouched EPA’s “rebuttable presumption” for 

uses specified in section 101(a)(2) of the Act. For additional discussion about the rebuttable 

presumption concept see response essay 5.i.

EPA disagrees with the comment that a UAA should not be required when an existing use is refined; that 

is, replaced by a more specific version of the use. The commenter is confusing existing uses with 

currently designated uses. An existing use is defined as “those uses actually attained in the water body 

on or after November 28, 1975, whether or not they are included in the water quality standard.” Title 40

of the Code of Federal Regulations (CFR) section 131.10(e). If a state or authorized tribe designates a 

sub-category of a use specified in section 101(a)(2) of the Act that requires criteria at least as stringent 

as previously applicable, then a UAA is not required per section 131.10(k)(2). However, if a state or 

authorized tribe is designating a sub-category of a use specified in section 101(a)(2) of the Act that 

requires criteria less stringent than previously applicable, then a UAA is required per section

131.10(j)(2). States and authorized tribes cannot remove a designated use if it is an existing use, per 

EPA’s regulations at section 131.10(h)(1). See also response essay 5.d re existing uses.

EPA acknowledges commenters who expressed confusion over the proposed language in section

131.10(k)(1); specifically, the proposed phrase “or has designated uses for a water body for the first 

time.” EPA recognizes that the language may appear unnecessary, however EPA’s intent with all of 

section 131.10(k) is to clearly mirror the language in section 131.10(j). More specifically, 40 CFR section

131.10(k)(1) is intended to mirror section 131.10(j)(1). This ensures that neither section can be 

interpreted to contradict the other. Please see subsection D of this essay for how EPA interprets the 

phrase “has designated” in the context of section 131.10(j) as that will also explain how it is to be 

interpreted in the context of section 131.10(k).

EPA agrees with comments that the final rule should be more specific about the meaning of the phrase 

“a designated use that is not specified in section 101(a)(2) of the Act” in section 131.10(k)(2) of the 

proposed rule, as such a phrase could be read in several different ways. EPA also agrees with comments 

that the final rule should specify that a UAA is not required to remove or “revise” a use that is specified 

in section 303(c)(2)(A) of the CWA but not specified in section 101(a)(2) of the Act (or subcategory of 

such a use). In response to these comments, in the final rule EPA revised section 131.10(k)(3) as follows: 

“The State wishes to remove or revise a designated use that is a non-101(a)(2) use...” In addition, EPA 

added a definition of “non-101(a)(2) use” to the final rule at section 131.3(q) that reads as follows: 

“Non-101(a)(2) use is any use unrelated to the protection and propagation of fish, shellfish, wildlife or 

recreation in or on the water.” A public water supply use (what commenters refer to as a “drinking 

water use”) is an example of a non-101(a)(2) use that may be removed without a UAA (provided such 

use is not an existing use), although states and authorized tribes must still submit documentation

regarding the water body’s “use and value” consistent with CWA section 303(c)(2)(A) and EPA’s 

implementing regulations to support the state or authorized tribe’s action. See section II.B of the 

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preamble to the final rule for additional discussion on removing or revising non-101(a)(2) uses and 

response essay 5.h. 

As far as whether exempting the removal of non-101(a)(2) uses from the requirement to conduct a UAA 

weakens the existing rule, see Essay 5.h. Note, however, that if tribal treaty or similar rights are at issue, 

the state and EPA would have to examine and ensure that applicable CWA WQS are consistent with 

those tribal rights. In exercising its authority to approve or disapprove state WQS, EPA must ensure that 

its decisions comply with any other applicable law, including federal treaties and statutes. In the several 

cases in which tribal treaty or similar rights have been raised in the context of a WQS action, EPA has 

taken a stepwise approach. First, EPA examines whether the tribal rights apply to the geographic area in 

question. Second, it determines what rights the tribe or tribes retain in the area. Third, it looks at 

whether those rights are affected by the proposed action. Much of this analysis will turn on the nature 

of the particular treaty or similar tribal rights, the type of decision EPA is making, and any assertions 

made by tribes in the course of consultation. Recently, EPA used tribal treaty rights or similar tribal 

reserved rights to inform the type of use that is in place as it reviewed the protectiveness of WQS

criteria. Any removal or modification of a designated use, whether it be a use specified in section

101(a)(2) (or a subcategory of such a use) or a non-101(a)(2) use, may also involve an analysis of such 

rights.

EPA disagrees with comments that the provision allowing states and authorized tribes to remove a non101(a)(2) use, such as a public water supply (referred to by commenter as drinking water) use, without a 

UAA should be deleted from the final rule. States’ and authorized tribes’ decisions regarding non101(a)(2) uses must still be consistent with the CWA and be transparent to both the public and to EPA, 

and any removal or revision of a non-101(a)(2) use is not exempt from an analysis. While the final rule at 

section 131.10(k)(3) makes it clear that a UAA is not required whenever a state or authorized tribe 

removes or revises a non-101(a)(2) use, the final rule also makes it clear that the state or authorized 

tribe must submit documentation justifying how its consideration of the use and value of the water for 

those uses listed in section 131.10(a) appropriately supports the state’s or tribe’s action. As discussed in 

the preambles to the proposed and final rules, as well as EPA’s responses to comments, this 

interpretation is reasonable and consistent with the CWA. See response essay 5.h. and section II.B of the 

final rule for additional discussion on removing or revising non-101(a)(2) uses, as well as additional 

discussion of what a “use and value” analysis might look like.

EPA disagrees with comments that the regulation at section 131.10(k) should be modified to clarify that 

a UAA is not required when a state or authorized tribe is correcting a default use that was assigned to a 

water body with no/insufficient/non-representative data, and in its place assigning a more appropriate 

use category based on new or refined data. EPA rejected this approach and instead, in 1983, codified 

40 CFR 131.10(k), which provides that a state or authorized tribe may forgo a UAA if it includes the CWA 

section 101(a)(2) goal uses in its use designations. EPA determined that such an approach is consistent 

with CWA section 510. See 48 Fed. Reg. at 51,401. Thus, EPA interpreted CWA section 101(a)(2) to 

create a presumption in favor of the uses identified therein – a presumption that could be rebutted 

upon a demonstration that those uses are not attainable. If the “more appropriate use” carries with it 

criteria that are at least as stringent as the criteria for the previously applicable “default use,” then 

section 131.10(k)(2) is clear that a UAA is not required. If it does not, then a UAA would be required, 

consistent with the CWA and EPA’s regulations. In EPA’s experience, revisions to correct a “default use” 

related to aquatic life and/or recreation are often a result of newly obtained or updated data that shows 

there are natural reasons why the designated use is not feasible to attain, such as naturally occurring 

pollutant concentrations or natural physical conditions of the water body. In such cases, the UAA could 

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be based on one of the factors representing unattainability due to “natural” reasons, which are 

sections 131.10(g)(1), 131.10(g)(2), and/or 131.10(g)(5).

F. Other General Comments

EPA acknowledges comments that the final rule should clarify the process and requirements for an 

acceptable UAA and what a “structured scientific assessment” requires and agrees that such clarity can 

be helpful. In section II.B of the preamble to the final rule, EPA discusses what states and authorized 

tribes need to consider when conducting a UAA. EPA will consider providing additional information on 

these topics when revising and/or developing guidance on uses after publication of the final rule. In 

addition, EPA encourages states and authorized tribes to work with their appropriate EPA Regional 

office, as needed, before conducting the UAA. EPA can provide early assistance in determining any 

existing uses and address any policy, legal, and/or technical questions that may arise. Early collaboration 

between states/tribes and EPA Regional representatives should significantly facilitate the UAA and WQS 

review processes. Therefore, it is important for the state or authorized tribe to send EPA the draft UAA 

before any WQS revisions are proposed. An even more effective approach would be to engage EPA 

during the development of a UAA protocol and to exchange information at the beginning, rather than 

the end, of the UAA process. There have been many such successful coordination efforts since EPA sent 

its March 2006 memorandum to the EPA Water Division Directors entitled “Improving the Effectiveness 

of the Use Attainability Analysis (UAA) Process.”

One commenter requested clarification on removing a public water supply (referred to by commenter as

drinking water) use that is no longer used for that purpose (e.g., the public water supply intake no 

longer exists). Per section 131.10(h)(1), a state or authorized tribe may not remove a use that is an 

existing use. For additional discussion on existing uses, please see response essay 5.d. Please also see 

EPA’s response to the State of Oklahoma regarding existing use questions at 

http://water.epa.gov/scitech/swguidance/standards/upload/Smithee-existing-uses-2008-09-23.pdf,

which specifically discusses the identification of existing public water supply uses.

Several commenters suggested that EPA modify the definition of a UAA at section 131.3(g) to provide 

flexibility on the level of effort and analysis required in a UAA, as a formal structured scientific 

assessment may not be necessary in all circumstances. One commenter suggested that EPA modify the 

definition of a UAA at section 131.3(g) to include only the uses specified in section 101(a)(2) of the Act.

EPA declines to make such revisions although EPA notes that today’s final rule includes additional 

language in 131.10(g) to make clear that a UAA conducted pursuant to 131.10(j) must demonstrate 

that attaining the use is not feasible because of one of the six factors listed in section131.10(g). EPA’s 

regulations and guidance have been clear that although all UAA’s must be structured scientific 

assessments, the level of effort and analyses varies with case-specific circumstances. Please see the 

case studies that EPA provides on its website at 

http://water.epa.gov/scitech/swguidance/standards/uses/uaa/casestudies_index.cfm. The purpose of 

these case studies is to show the varying degree of analysis that was involved in these UAAs from simple 

to complex depending on the specific facts. In regards to modifying the definition to include only the 

uses specified in CWA section 101(a)(2), EPA’s regulations make clear that a UAA is only required when 

removing or revising uses specified CWA section 101(a)(2) or subcategories of such a use. However, 

UAAs can be valuable tools for a state or authorized tribe to evaluate any designated use, even when 

considering the use and value of a non-101(a)(2) use. For these reasons, EPA is not revising the 

definition of a UAA. 

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Numerous commenters stated that UAAs should be conducted prior to adopting any of the uses 

specified in section 101(a)(2) of the Act. Other commenters suggested that EPA encourage or require 

states and authorized tribes to review the attainability of uses before a total maximum daily load 

(TMDL) is adopted. For a response to these comments, please see response essays, 5.i and 5.j.

EPA disagrees with the comment that it should modify the regulation to clarify that a UAA is not 

required to remove consumption of aquatic organisms by humans, if such organisms are not naturally 

found in the water body. For discussion response to on this comment, please see response essay 5.j.

EPA acknowledges the comment that EPA should encourage states and authorized tribes to take into 

account the difference in risk between primary and secondary contact recreation activities; however, 

this comment is outside the scope of this rulemaking because EPA did not propose or request comment 

how to do UAAs for specific designated uses and such a comment asks EPA to provide certain guidance 

rather than commenting on the regulatory requirements. EPA is currently performing a systematic 

review of the literature to better understand the difference in risk between primary and secondary 

contact recreation uses. This study may provide data and information that is useful to EPA, states, and 

other stakeholders in understanding the level of protection needed for secondary contact recreation 

uses. EPA will consider providing additional information on conducting UAAs in subsequent guidance 

after the final rule is published. For discussion on adopting criteria to protect the HAU, please see 

response essay 5.f.ii.

EPA acknowledges the comments that UAAs should be used in limited circumstances, as well as 

comments that UAAs are underutilized and EPA should encourage more UAAs. EPA refers the 

commenters to the final rule language at sections 131.10(j) and (k). These provisions describe the 

circumstances when a UAA is and is not required. For the reasons described in EPA’s 1983 WQS 

regulation, the preambles to the proposed and final rule, and the responses to public comments on the 

proposed rule, EPA’s regulations reasonably delineate between the scenarios in which a UAA is required 

and when a UAA is not required. Whether UAAs should more used more sparingly or more frequently

than they have been over the last 30-40 years is an issue that is outside the scope of this rulemaking.

EPA agrees with comments that the revisions in section 131.10 are prospective in nature and do not 

require states and authorized tribes to immediately revisit designated uses that are already adopted and 

in effect. However, it is important to remember that states and authorized tribes cannot ignore changes 

in attainability of uses once they are adopted and applicable. 40 CFR section 131.20 requires states and 

authorized tribes to hold public hearings for the purposes of reviewing applicable WQS from time to 

time, but at least once every three years. Specific to uses, the regulations go on to say that “The State 

shall also re-examine any waterbody segment with water quality standards that do not include the uses 

specified in section 101(a)(2) of the Act every 3 years to determine if any new information has become 

available. If such new information indicates that the uses specified in section 101a)(2) of the Act are 

attainable, the State shall revise its standards accordingly.” In addition, EPA’s regulation at section

131.10(i) requires states and authorized tribes to revise its standards to reflect the uses actually being 

attained if the currently applicable WQS specify designated uses less than what is presently being 

attained. Thus, while the revisions to section 131.10 are prospective in nature, states and authorized 

tribes must also comply with the rest of EPA’s WQS regulation. 

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Essay 5.h – Designated Uses: Removing Uses Other than Recreational or 

Aquatic Life Uses

A. General Support

The U.S. Environmental Protection Agency (EPA) appreciates the support expressed by commenters for 

the revisions that clarify that a use attainability analysis (UAA) is not required when states and 

authorized tribes remove or revise non-101(a)(2) uses (i.e., any use that is not related to the protection 

or propagation of fish, shellfish, wildlife or recreation in or on the water). 

B. General Opposition

a. Comments That the Regulation Does Not Limit Use Attainability Analyses to the Uses 

Specified in Section 101(a)(2) of the Clean Water Act

EPA disagrees with comments that the regulatory requirements at section 131.10(j) prior to today’s rule

do not limit UAAs to only the uses specified in section 101(a)(2) of the Act, and by doing so through the 

final rule, EPA is focusing too narrowly on the uses specified in section 101(a)(2) of the Act and 

weakening protections for non-101(a)(2) uses. As explained in the proposal preamble, EPA 

acknowledged that the regulations relating to the UAA requirement as previously written were 

ambiguous and in its 1998 Advance Notice of Proposed Rulemaking (ANPRM) EPA interpreted its 

regulations as requiring demonstration of a 131.10(g) factor for all use removals . However, EPA 

explained the rationale for its regulatory revision in the preamble to the proposed rule (See 78 FR 

54524-25) based on a better interpretation of the Clean Water Act (CWA) and regulation and 

appropriately sought public comments on its proposed revision. Today’s final rule revises sections 

131.10(g) and 131.10(j) so that when the provisions are read together, it is clear that the factors at 

section 131.10(g) are only required to be considered when a state or authorized tribe conducts a UAA 

under section 131.10(j) and not for non-101(a)(2) uses such as public water supply. See Response 

Essay 5.g for additional discussion on the link between sections 131.10(g), (j) and (k).

b. Comments That EPA Is Removing Protections for Non-101(a)(2) Uses

EPA disagrees with comments that the final rule is removing protections for non-101(a)(2) uses such as 

public water supply. In response to comments that there was little discussion over what justification is 

needed to remove a non-101(a)(2) use, EPA added clarifying language in 131.10(a) and (k) explaining 

that when designating and removing non-101(a)(2) uses “states must submit documentation justifying 

how its consideration of the use and value of water for those uses listed in 131.10(a) appropriately 

supports the state’s or authorized tribe’s action.” EPA refers to this documentation as a “use and value 

demonstration.” These requirements are consistent with EPA’s previously existing regulation at 

131.10(a) and 131.6. Section 131.10(a) already provided that states and authorized tribes “must specify 

appropriate water uses to be achieved and protected” and that the “classification of the waters of the 

[s]tate must take into consideration the use and value of water for public water supplies, protection and 

propagation of fish, shellfish and wildlife, recreation in and on the water, agricultural, industrial, and 

other purposes including navigation”). Section 131.6(a) and (b) already provided that states and 

authorized tribes must submit to EPA for review “use designations consistent with the provisions of 

sections 101(a)(2) and 303(c)(2) of the Act” and “[m]ethods used and analyses conducted to support 

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WQS revisions.” As such, today’s rule at 131.10(a) and (k)(3) continue to implement 303(c)(2)(A) by 

ensuring that states’ and authorized tribes’ non-101(a)(2) uses are established taking into consideration 

the use and value of the water “and that standards continue to protect public health or welfare, 

enhance the quality of the water and serve the purposes of the Act, including the objective of the Act.”

These requirements will provide EPA with both a record and standard by which it can reasonably 

exercise its oversight authority when states and authorized tribes designate and remove any use, 

particularly non-101(a)(2) uses. EPA notes that, as previously required, all supporting analyses for a 

water quality standards (WQS) revisions must be made available to the public prior to a hearing (Title 40

of the Code of Federal Regulations (CFR) section 131.20(b)). 

The provisions in section131.10 unchanged by today’s rule continue to apply as they applied prior to 

today’s rule. In response to public comments, EPA is clarifying that the provisions protecting 

downstream waters at section 131.10(b) and prohibiting removal of a designated use if it is an existing 

use at section 131.10(h)(1). The requirements in section 131.10 represent reasonable protections to 

ensure that when states and authorized tribes are designating or removing non-101(a)(2) uses they are 

appropriately justifying their decisions to adopt a particular use consistent with the Act and maintaining 

and restoring water quality consistent with the objective of the Act. EPA disagrees with commenters 

that noted that EPA is removing the existing use requirement. As explained in essay 5.d. EPA did not 

reopen or revise the existing use requirement resides in 131.10(h)(1).

The regulatory factors in section 131.10(g), untouched by this rule, implemented the “wherever 

attainable” language in 101(a)(2).Today’s rule narrows the specified circumstances in which a state must 

demonstrate, through a structured scientific analysis (i.e., a UAA), that one of the factors listed at 

section 131.10(g) precludes attainment of the use, to the circumstances listed in section 131.10(j) which 

involve designation and removal of uses specified in section 101(a)(2) of the Act and subcategories of 

such uses. This narrowing of when the specialized analysis of a UAA must be conducted and the 

requirement to adopt the highest attainable use (HAU) are consistent with EPA’s implementation of the 

CWA to differentiate between the uses specified in CWA section 101(a)(2) and 303(c)(2)(A) given 

303(c)(2)(A)’s requirement that WQS must serve the purposes of the Act, which include the goal for water 

quality that provides for the protection and propagation of fish, shellfish, and wildlife and recreation in and 

on the water, wherever attainable. This approach recognizes that non-101(a)(2) uses are still important 

and worthy of protection and careful consideration but accounts for the nature and variety among the 

non-101(a)(2) uses that justifies more flexibility for states and authorized tribes to describe the use and 

value of such uses after a public process consistent with section 131.20(b). Today’s preamble further

recognizes that while the factors in 131.10(g) may be helpful to guide a state’s or authorized tribe’s 

consideration of non-101(a)(2) uses and provides that UAAs may qualify as a “use and value 

demonstration,” states and authorized tribes are not limited to using these attainability factors when 

making decisions about designating and removing non-101(a)(2) uses consistent with section 131.10(a). 

For example, EPA now recognizes that use and value considerations relating to industrial uses may be very 

different from considerations relating to public water supply and that while the factors relating to 

attainability may be relevant for some non-101(a)(2) designated use decisions, other relevant factors may 

be more appropriate for a state’s or authorized tribe’s consideration of use and value. When discussing the 

factors at 131.10(g), EPA explained in its 1998 ANPRM that “ [t]he use removal criteria were included in 

the regulation to address those circumstances where the attainability of certain uses would be precluded 

by conditions over which the water quality protection provisions in the regulation had little or no control. 

The uncontrollable conditions considered most likely to limit attainability were: natural water quality or 

habitat limitations, irretrievable human caused contamination or conditions, or insupportable economic 

and social costs. These general conditions, then, formed the basis for the six use removals.” [at cite to 

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36754]. Therefore, narrowing of the UAA requirement provides states and authorized tribes with 

reasonable discretion to consider other factors that may be relevant when considering non-101(a)(2) uses. 

EPA notes that consideration of the use and value for non-101(a)(2) uses would take into account 

considerations consistent with the requirement in 303(c)(2)(A) that standards “shall be such as to protect 

public health or welfare or enhance the quality of the water.”

C. Comments Related to Highest Attainable Use

EPA disagrees with comments stating that the HAU concept should apply to all uses and not solely to the 

uses specified in section 101(a)(2) of the Act. EPA clarifies that the concept of “attainability” comes 

directly from the language of CWA section 101(a)(2) and the purpose of the HAU requirements is to 

establish designated uses that continue to serve the purpose of the act for water quality protecting the 

uses specified in CWA section 101(a)(2), even where the uses specified in CWA section 101(a)(2) are 

demonstrated to be unattainable. Section 101(a) of the CWA provides that the ultimate objective of the 

Act is to restore and maintain the chemical, physical, and biological integrity of the Nation’s waters. The 

interim goal expressed in CWA section 101(a)(2) is water quality that provides for the protection and 

propagation of fish, shellfish, and wildlife and recreation in and on the water “wherever attainable.” In 

order to ensure that states and authorized tribes adopt WQS that serve the Act’s goal of water quality 

that provides for the uses specified in section 101(a)(2) of the Act to the extent attainable and enhance 

the quality of the water, the final rule requires that where states and authorized tribes adopt new or 

revised WQS by demonstrating that a use specified in section 101(a)(2) of the Act or a subcategory of 

such a use is unattainable, based on a required UAA, they must adopt the HAU. EPA’s 1983 regulations 

established the basis for the rebuttable presumption of the uses specified in section 101(a)(2) of the Act,

wherever attainable, and established the requirement to conduct a UAA and the six factors in 131.10(g). 

Today’s rule continues the 1983 approach to implementing the CWA to differentiate between the uses 

specified in CWA section 101(a)(2) and 303(c)(2)(A) by clarifying in rule that the requirement to conduct 

a UAA only applies to the circumstances specified in section 131.10(j) and that the requirement to adopt 

the HAU is only triggered when the state or authorized tribe is adopting a new or revised WQS based on 

a required UAA. These requirements are a key component to ensuring that WQS provide a sound 

foundation that continues to serve that 101(a)(2) goal. While EPA recognizes that all designated uses are 

important and warrant careful consideration when a state or authorized tribe is designating or revising 

uses for a waterbody, EPA is implementing the Act to provide specialized requirements relating to 

designation and revision of the uses specified in 101(a)(2) and subcategories of such uses to best 

achieve that statutory goal. Please see EPA’s discussion in section B of this essay for further discussion 

on why the regulations provide additional, specialized requirements for the uses specified in CWA 

section 101(a)(2) and subcategories of such uses.

EPA disagrees with the commenters who stated that the HAU requirement appears to override the 

classification of waters on the 303(d) list that are impaired. The former is about use attainability (i.e., a 

prospective consideration of whether a use may be attainable in the future) for purposes of establishing 

objective desired condition for the specified water body through the designation of a use, whereas the 

latter is about whether a water body is currently meeting or attaining its WQS. A water body that is not 

currently attaining its WQS and still requires a total maximum daily load (TMDL) is considered impaired 

and in most cases would be placed on a 303(d) list for TMDL development. A water body that is 

appropriately designated at its HAU may still be on the CWA 303(d) list as impaired because it isn’t 

meeting the HAU (i.e., the desired condition for the waterbody, “whether or not [it] is being attained” 

(see section 131.3(e)). The TMDL process can facilitate identification of targets and activities necessary 

to implement in order to achieve the HAU. Therefore, the HAU requirement works to ensure that water 

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quality goals reflected in a state’s or authorized tribe’s WQS provide a strong foundation for CWA 

implementing programs, including those under CWA section 303(d). See Response Essay 5.j for 

additional discussion on the link between the use refinement process and TMDL development.

D. Comments Related to Use Attainability Analyses and Existing Uses

EPA disagrees with comments suggesting that a UAA be conducted whenever a state or authorized tribe 

adopts new or revised WQS based on a CWA section 101(a)(2) use, in order to ensure attainability of 

such use(s). As described in section II.B of the preamble to the final rule, EPA’s prior existing WQS 

regulation at 40 CFR Part 131 interprets and implements CWA sections 303(c)(2)(A) and 101(a)(2) 

through requirements that WQS protect the uses specified in CWA section 101(a)(2) unless states and 

authorized tribes show those uses are unattainable through a UAA, effectively creating a rebuttable 

presumption of attainability. As such, a UAA is required in the context of CWA 101(a)(2) uses when a 

state or authorized tribe either removes or revises a use specified in section 101(a)(2) of the Act (or a 

sub-category of such use). 40 CFR 131.10(k) provides when a UAA is not required. During the 1983 

rulemaking, there was considerable comment regarding whether and, if so, when UAAs should be 

required. See 48 Fed. Reg. at 51,401. Some commenters, like those commenting today, suggest a UAA 

be conducted whenever a state or authorized tribe adopts new or revised WQS based on a CWA section 

101(a)(2) use, in order to ensure attainability of such use(s), so that recreation uses “in and on the 

water,” for example, could be designated only when the state or authorized tribe had affirmatively 

demonstrated that such uses were attainable. See id. EPA rejected this approach and instead, in 1983, 

codified 40 CFR 131.10(k), which provides that a state or authorized tribe may forgo a UAA if it includes 

the CWA section 101(a)(2) goal uses in its use designations. EPA determined that such an approach is 

consistent with CWA section 510. See 48 Fed. Reg. at 51,401. Thus, EPA interpreted CWA 

section 101(a)(2) to create a presumption in favor of the uses identified therein – a presumption that 

could be rebutted upon a demonstration that those uses are not attainable. While today’s rule made 

edits to 131.10 (j) and (k), such revisions did not substantively change the fundamental requirements in 

these provisions established in the 1983 regulations. Edits made in today’s rule to 131.10(j) and (k) were 

made to improve readability, provide clarity in the distinction between the two clauses of (j)(2) by 

specifying that (j)(2)’s reference to less stringent criteria refers to previously applicable criteria, revise 

the language to ensure that both provisions do not conflict and are true inverses of each other 

consistent with the 1983 regulations, and to add a reference to 131.10(a).

EPA disagrees with a commenter who states that removing the UAA requirement would allow states or 

authorized tribes to remove designated uses, including non-101(a)(2) uses, for any reason, such as if the 

state or authorized tribe does not want to regulate sources of pollution. As discussed above, 131.10(a) 

now makes explicit that states and authorized tribes must submit to EPA documentation justifying how 

its consideration of the use and value of water appropriately supports the state’s or authorized tribe’s 

designation or removal of uses. A UAA may be used to satisfy this requirement. In addition this “use and 

value demonstration” must be provided to the public prior to a public hearing. While there is discretion 

provided to states and authorized tribes when providing a use and value demonstration to remove or 

revise non-101(a)(2) uses, the state or authorized tribe must still meet the applicable regulatory 

requirements. Therefore, EPA disagrees that states and authorized tribes will be able to designate and 

remove uses “arbitrarily” or “for any reason” because states and authorized tribes will need to engage in 

careful consideration consistent with the specified requirements at section 131.10 and address public 

comments on such considerations to ensure that their WQS actions regarding use revisions, particularly 

designations and removal of non-101(a)(2) uses, are appropriately supported in their documentation 

submitted to EPA.

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EPA received a comment asking “Is it possible to remove a designated use even though it has never

reached the existing use standard or is no longer used for that use.” As discussed above, EPA’s provision 

at section 131.10(h)(1) prohibits the removal of a designated use if it is an existing use. However, EPA 

also provides a clear interpretation of the definition of an existing use in 131.3(e). Please see the 

preamble to the final rule and response essay 5.d. for additional discussion on determining the existing 

use. Please also see EPA’s 2008 letter at 

http://water.epa.gov/scitech/swguidance/standards/upload/Smithee-existing-uses-2008-09-23.pdf for a 

specific discussion on determining the existing use for public water supply uses.

E. Other Comments

EPA acknowledges a commenter’s concerns with assumptions made in a state-specific hydrology 

protocol, as well as an associated expedited UAA work sheet. Comments addressing states specific 

situations are outside the scope of this rulemaking which is national in scope. EPA will work with specific 

states and authorized tribes, as necessary, to determine what changes are necessary to meet the 

requirements of the final rule.

EPA acknowledges commenters who suggest that the removal of non-101(a)(2) uses, such as a public 

water supply use or agricultural use, and associated criteria may have the unintended consequence of 

affecting uses specified in section 101(a)(2) of the Act. For example, a state may choose to remove an 

agricultural use that is protected by chloride and sulfate criteria. The removal of such criteria may

negatively impact the aquatic life use, as the aquatic life in the specified water body are also sensitive to 

these pollutants, and the state has not adopted criteria for chloride and sulfate to specifically protect 

the aquatic life use. EPA is finalizing a specific definition for non-101(a)(2) uses to clearly distinguish 

these uses from the uses specified in 101(a)(2) of the Act and subcategories of uses specified in 

101(a)(2) of the Act. EPA has found that some have interpreted EPA’s use of the term non-101(a)(2)

uses, in the past, to also mean subcategories of uses specified in 101(a)(2) which has led to confusion.

EPA’s formal adoption of a definition is intended to avoid this confusion. While EPA’s definition of a non101(a)(2) use is framed in the context of a use that is “unrelated to the protection and propagation of 

fish, shellfish, wildlife or recreation in or on the water” it is important to understand that the association 

of a criterion for a parameter or constituent that does affect the protection and propagation of fish, 

shellfish, wildlife or recreation in or on the water does not convert a non-101(a)(2) use to a use specified 

in 101(a)(2) (or a subcategory of such a use). 40 CFR 131.11(a) requires states and authorized tribes to 

adopt criteria that protect the designated use and that such criteria must contain sufficient parameters 

or constituents to protect the designated use. Therefore, continuing with the example, to the extent 

that there are criteria for certain parameters or constituents that protect the aquatic life use and will be 

removed by removing the agricultural use, states and authorized tribes must also adopt the criteria for 

these parameters or constituents (to protect the aquatic life use) in the same action or conduct a UAA 

demonstrating that the aquatic life use is not attainable before EPA can approve the removal of the 

agricultural use and corresponding criteria as consistent with the CWA and EPA’s regulation.

For a response on comments that states and authorized tribes should not be required to look at future 

attainable uses based on considerations such as the potential effectiveness of best management 

practices (BMPs), please see response essay 5.f.i.

EPA acknowledges a comment received regarding variances and non-101(a)(2) uses. See Response 

Essay 8.g.iv for discussion on the type of documentation required to demonstrate the need for a WQS 

variance for non-101(a)(2) uses. 

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Attainability

Essay 5.i – Designated Uses: EPA’s Regulations and Rebutting the 

Presumption of Attainability

A. Comments on EPA’s Statutory and Legal Authority

Comments raised issues concerning the U.S. Environmental Protection Agency’s (EPA’s) regulations 

dealing with section 131.10(j) and (k), which the net effect of these two provisions is to require that 

water quality standards (WQS) provide for uses specified in section 101(a)(2) of the Act unless those 

uses have been shown to be unattainable consistent with EPA’s regulations. For ease of reference, EPA 

has historically referred to these provisions as establishing a “rebuttable presumption” approach when 

states are adopting new or revised designated uses. Commenters argue that this approach is not 

supported by the Clean Water Act (CWA). Commenters provided multiple rationales in support of their 

position, such as 1) the “rebuttable presumption” ignores the plain language of section 101(a)(2) of the 

Act (i.e., “wherever attainable, an interim goal of water quality which provides for the protection and 

propagation of fish, shellfish, and wildlife and provides for recreation in and on the water” (emphasis 

added)); 2) the “rebuttable presumption” inappropriately usurps the authority given to states and 

authorized tribes by Congress to designate their own uses; 3) the “rebuttable presumption” turns an 

abstract goal into a requirement and it is inappropriate to assume the uses specified in section 101(a)(2) 

of the Act are attainable on all waters, as many waters were designated without consideration for 

attainability. 

EPA’s 1983 regulations, specifically section 131.10(j) and (k), interpret and implement the CWA through 

requirements that WQS protect the uses specified in CWA section 101(a)(2) unless states and authorized 

tribes show those uses are unattainable through a use attainability analysis (UAA) consistent with EPA’s 

regulation, effectively creating a rebuttable presumption of attainability. Although EPA made clarifying 

revisions to the language in section 131.10(j) and (k), as discussed in response essay 5.g, the underlying 

requirement was not a subject of this rulemaking and remains unchanged by today’s rule. The revisions

do not change the fundamental requirement to do a UAA where the state/authorized tribal standards 

do not reflect uses specified in section 101(a)(2) or where a state or authorized tribe is removing or 

modifying related uses. In addition, EPA kept the same basic structure that section 131.10(j) sets forth 

when a UAA is required and section 131.10(k) sets forth when a UAA is not required. The most 

substantive changes EPA made to section 131.10(j) and (k) are to make clear that UAAs are not required 

for non-101(a)(2) use removals, which leaves untouched the underlying requirements of the 1983 

regulations for uses specified in section 101(a)(2) of the Act. It is unclear what commenters mean when 

stating that today’s rule “codifies” or “advanced” the rebuttable presumption. To the extent that they 

mean that today’s rule somehow changes the regulations to fundamentally require something new, EPA 

disagrees. In the proposal preamble, the background section explained the existing requirements in 

EPA’s 1983 regulations to provide context for a discussion of the clarifying revisions in the proposed 

rule. EPA is providing an explanation regarding the regulations that effectively create a rebuttable 

presumption in this response to comment for much the same purpose and to dispel any confusion and 

misunderstanding regarding EPA’s revisions in the final rule.

The Agency’s decades-long interpretation of the CWA and EPA’s regulatory provisions at (j) and (k) as 

effectively creating a rebuttable presumption dates back to when EPA promulgated those regulations in 

1983. EPA did not receive any facial challenges to those regulations promulgated in 1983. EPA’s 1983 

preamble explained that “[u]nder the final regulation, whenever States have set or set uses for a water 

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Attainability

body which do not include all of the uses specified in Section 101(a)(2) of the Act, they must conduct a 

UAA to demonstrate that the uses are unattainable.” Water Quality Standards Regulations, 48 Fed. Reg. 

51400, 51409 (November 8, 1983). EPA has implemented the regulations consistent with its authorities 

by acting on the relevant goal use being addressed by the state or authorized tribe in its new or revised 

WQS. For example, if the state or authorized tribe designates a waterbody for secondary contact 

recreation in the first instance, then the state or authorized tribe would only need to do a UAA to justify 

that primary contact recreation is not attainable. During the 1983 rulemaking, there was considerable 

comment regarding whether and if so, when UAAs should be required. See 48 Fed. Reg. at 51,401. Some 

commenters asserted that EPA should require UAAs only when a state or authorized tribe intends to 

designate a use specified in CWA section 101(a)(2), so that section 101(a)(2) uses of the Act could be 

designated only when the state or authorized tribe had affirmatively demonstrated that such uses were 

attainable. EPA rejected this approach and instead, in 1983, codified Title 40 of the Code of Federal 

Regulations (CFR) section 131.10(k), which provides that a state or authorized tribe may forgo a UAA if it 

includes the CWA section 101(a)(2) goal uses in its use designations. EPA determined that such an 

approach is consistent with CWA section 510. See 48 Fed. Reg. at 51,401.

Moving forward from 1983, EPA has taken actions based on this interpretation numerous times over the 

years. In 1997, EPA promulgated a “cold water biota” aquatic life use for specified water bodies in Idaho 

that EPA had earlier disapproved. In the preambles to the proposed rule, EPA discussed the 

requirements of the regulations and how they effectively create a rebuttable presumption as follows:

Section 101(a)(2) of the Clean Water Act states the national goal of achieving by July 1, 1983, 

‘‘water quality which provides for the protection and propagation of fish, shellfish, and wildlife 

and * * * recreation in and on the water,’’ wherever attainable. These national goals are 

commonly referred to as the ‘‘fishable/swimmable’’ goals of the Clean Water Act. Section 

303(c)(2)(A) requires water quality standards to ‘‘protect the public health and welfare, enhance 

the quality of water, and serve the purposes of this Act.’’ EPA’s regulations at 40 CFR Part 131 

interpret and implement these provisions through a requirement that water quality standards 

provide for fishable/swimmable uses unless those uses have been shown to be unattainable, 

effectively creating a rebuttable presumption of attainability... Proposal, 62 FR 23004, 23006, 

April 28, 1997. 

...As stated in the proposed rule, in designating beneficial uses, EPA is relying on the rebuttable 

presumption implicit in the CWA and EPA’s regulations at 40 CFR part 131, that in the absence of 

data to the contrary, ‘‘fishable’’ uses are attainable. As discussed above, the record supports the 

reasonableness of this presumption, and none of the comments rebutted it with respect to any of 

the water bodies for which EPA is promulgating designated uses....

Final rule, 62 FR 41162, 41166, July 31, 1997. 

EPA’s 1983 regulation and its interpretation of section 131.10(j) and (k) were challenged along with 

EPA’s action in Idaho. See Idaho Mining Association, Inc. v. Browner, et al., 90 F.Supp.2d 1078, 1092 

(D. Idaho 2000). The court entertained an “as-applied” challenge to the regulation and upheld both the 

1983 regulation and “the rebuttable presumption stemming therefrom.” Id. at 1097. Specifically, the 

Idaho Mining Association challenged EPA’s reliance on its interpretation of the regulations effectively 

creating a rebuttable presumption in the Agency’s promulgation of aquatic life use designations in 

Idaho.

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In EPA’s brief in support of its motion for summary judgment and in response to plaintiff’s motion for 

summary judgment, EPA explained that:

...EPA’s regulations reasonably implement the applicable sections of the CWA. Although Plaintiff 

is correct that the CWA does not mandate the attainment of fishable/swimmable uses on all 

waters, the Act is not indifferent to this goal. (citation omitted). The overriding purpose of the 

Act is “to restore and maintain the chemical, physical, and biological integrity of the Nation’s 

waters” through reduction and eventual elimination of the discharge of pollutants into those 

waters by 1985. 33 U.S.C. §1251(a) & (a)(1) (emphasis added). Congress intended, “wherever 

attainable,” to “provide[] for the protection and propagation of fish, shellfish, and wildlife and 

provide[] for recreation in an on the water.” 33 U.S.C. §1251(a)(2). The Act exists to force 

reductions in pollution and thus improve the quality of the Nation’s waters, not simply to 

administer the status quo.

Plaintiff is also correct that the CWA does not mandate how attainability is to be evaluated. 

(citation omitted). Rather the Act emphasizes that water quality standards should help achieve 

the purposes of the Act, and it provides a list of factors to consider in establishing such 

standards. (citations omitted).

The lack of statutory specificity does not justify Plaintiff’s leap in logic that EPA exceeded its 

authority by requiring fishable/swimmable designated uses unless a UAA shows that such uses 

are unattainable (i.e., the rebuttable presumption). To the contrary, the Supreme Court has held 

that, where a statute is subject to multiple interpretations, the interpretation of the agency 

charged with enforcing the statute is entitled to substantial deference.

In Chevron U.S.A., Inc. v. Natural Resources Defense Council, Inc., 467 U.S. 837 (1984), the 

Supreme Court reviewed EPA’s interpretation of “stationary source” under the Clean Air Act.

EPA’s regulations allowed multiple pollution-emitting devices with a single plant to be treated as 

one “stationary source,” as if they were under a single “bubble.” The Clean Air Act required 

permits for “new or modified major stationary sources” of air pollution, but did not further 

define “stationary source.” Id. at 840. Because “Congress itself had not commanded [a] 

definition,” id. at 841, and because EPA’s definition was reasonable, the Court upheld EPA’s 

regulation. The Court explained that review of agency regulations implementing a statute is a 

two-step inquiry:

First, always, is the question whether Congress has directly spoken to the precise 

question at issue. If the intent of Congress is clear, that is the end of the matter; for the 

court, as well as the agency, must give effect to the unambiguously expressed intent of 

Congress. If, however, the court determines Congress has not directly addressed the 

precise question at issue, the court does not simply impose its own construction of the 

statute, as would be necessary in the absence of an administrative interpretation.

Rather, if the statute is silent or ambiguous with respect to the specific issue, the 

question for the court is whether the agency’s answer is based on a permissible 

construction of the statute.

Chevron, 468 U.S. at 842-43.

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In the case at bar, Congress has not “directly spoken to the precise question at issue,” 

specifically, what showing should be required for a water body to avoid (or receive) a particular 

designated use, including “fishable/swimmable.” The statute provides only a list of factors to 

consider and an admonition that WQS “shall be such as to ... serve the purposes of [the Act].” 

CWA section 303(c)(2)(A). Of the range of regulatory choices that can be imagined (e.g., 

fishable/swimmable uses must be demonstrated not to be attainable; best guess designations 

based on available data; fishable/swimmable uses must be demonstrated not to be attainable),

EPA’s regulations are reasonable and consistent with the statute’s overall purpose of restoring 

and maintaining the integrity of the Nation’s waters, and the more specific goal of attainable 

101(a)(2) uses wherever possible. See 48 Fed. Reg. 51,409 [col. 3] (EPA’s response to comments 

when adopting the 1983 final rule).

EPA Op. Br. 19-21.

EPA’s reply brief also explained that:

...By allowing designation uses less protective than “fishable/swimmable” but requiring a UAA to 

justify such designations, EPA’s regulations do not bar the designation of any of the uses listed in 

CWA Section 303(c)(2)(A) [citation omitted]. Rather, EPA’s regulations simply ensure that 

fishable/swimmable uses will not be written off unless they are truly not attainable.

Nothing in CWA Section 303(c)(2)(A) prohibits such a balancing of uses. The sentence 

highlighted by Plaintiff reads:

Such [revised or new water quality] standards shall be established taking into 

consideration their use and value for public water supplies, propagation of fish and 

wildlife, recreational purposes, and agricultural, industrial, and other purposes, and also 

taking into consideration their use and value for navigation.

(citation omitted). Nothing in this sentence, or this section of the CWA specifically states how 

these various and sometimes conflicting uses shall be balanced and weighed against each other. 

Nor does this sentence say anything about what ends the standards should accomplish. Thus 

even if the Act said nothing else about designated uses, the statute’s silence permits EPA, 

following Chevron and its progeny, to adopt reasonable approaches to striking a balance among 

these uses. (citation omitted).

But the Act does, in fact, give some general guidance regarding the balance to be struck among 

the listed uses. The sentence prior to the on[e] highlighted by Plaintiff explains:

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.

33 U.S.C. §1313(c)(2)(A). The clear direction of these three objectives is toward more protective, 

not less protective water quality standards. As we showed in our opening brief that “the 

purposes of [the CWA] referenced in this sentence expressly include attaining fishable and 

swimmable uses whenever possible.” (citation omitted). The objective of “enhance[ing] the 

quality of water similarly favors more protective designated uses, as does the objective of 

protecting public health. Indeed, only the reference to public welfare is conceived broadly to 

include uses that tend to degrade water quality...In sum, the Act leaves EPA to set minimum 

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requirements for weighing the listed uses and it supports EPA’s determination to strike a 

balance that favoring “fishable/swimmable” uses absent solid evidence that those uses are not 

attainable.” 

EPA Reply Br. 19-21.

The court agreed with EPA’s arguments and upheld both the EPA’s regulation and the interpretation:

...In this case, the Court agrees with Defendants that Congress has not directly spoken to the 

precise question at issue, i.e. “what showing should be required for a water body to avoid (or 

receive) a particular designated use.” (citations omitted). Instead, Section 303(c)(2)(A) of the 

CWA merely provides a list of competing factors/uses to be considered when establishing water 

quality standards without providing any specific guidance as to how those factors should be 

weighed or balanced against one another. In light of this ambiguity, the Court must proceed to 

the second step of the Chevron inquiry and determine whether the EPA’s presumptive 

fishable/swimmable use interpretation is a permissible construction of the statute. For the 

following reasons, the Court finds that it is.

In promulgating its 1983 regulations and the challenged rule, the EPA did not unreasonably 

exclude any of the factors contained in section 303(c)(2)(A) from consideration. Instead, it 

merely exercised its discretion to balance those factors in favor of a fishable/swimmable use 

designation unless a UAA demonstrates that such uses are not attainable. In the Court’s view, 

the EPA’s presumptive use interpretation is consistent with Congress’ express directive that 

water quality standards be such as to “protect the public health or welfare, enhance the quality 

of water and serve the purposes of [the CWA].” Section 303(c)(2)(A), 33 U.S.C. § 1313(c)(2)(A). 

Undeniably, one of the over-arching purposes of the CWA is to achieve fishable/swimmable uses 

wherever attainable. Section 101(a)(2), 33 U.S.C. § 1251(a)(2). Thus, although Congress 

recognized that the achievement of fishable/swimmable uses will not always be possible, it 

clearly indicated an intent that states move toward more protective water quality standards to 

preserve the nation’s waters for human uses as well as for aquatic life. The EPA’s regulations at 

40 C.F.R. § 131.10(j) and (k), and the rebuttable presumption stemming therefrom, are plainly 

consonant with this intent and represent a “reasonable accommodation of conflicting policies 

that were committed to the agency’s care by” section 303(c)(2)(A) of the CWA. (citations 

omitted.) Accordingly, the Court finds that the EPA’s presumptive use interpretation is a 

permissible construction of the statute and is therefore entitled to deference from this Court....

Based upon the foregoing, the Court concludes that the EPA permissibly relied upon a 

rebuttable presumption of fishable/swimmable use attainability in promulgating the challenged 

rule. The use of the rebuttable presumption in favor of fishable swimmable uses was not a new 

and unauthorized interpretation of the CWA but was instead a reasonable interpretation of the 

EPA’s existing regulations at 40 C.F.R. § 131.10(j) and (k). Furthermore, although the CWA does 

not require fishable/swimmable use designations for all waters of the United States, the EPA 

clearly acted within the bounds of its statutory authority in creating the presumption to further 

the mandatory goals and purposes of the Act. Thus, the Court finds that the actions of the EPA 

in relying on the rebuttable presumption in this case were neither arbitrary and capricious nor 

an abuse of discretion... 

Idaho Mining Association, Inc. v. Browner, et al., 90 F.Supp.2d 1078, 1097-98, 1107 (D. Idaho 2000). 

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In subsequent decisions, EPA applied the same interpretation of its regulations. In 1998 and 2002, EPA 

proposed two WQS rules in Alabama that were never finalized. These proposed rules included a “fish 

and wildlife” use (i.e., uses specified in section 101(a)(2)) for certain waters where EPA had disapproved 

an “agricultural and industrial water supply” use. The disapproval found that the State had not provided 

an adequate demonstration that the use specified in section 101(a)(2) was infeasible to attain (i.e., the 

State had not adequately rebutted the presumption that the use specified in section 101(a)(2) was

attainable). Again, the preambles to the proposals discussed EPA’s regulations establishing a rebuttable 

presumption:

As discussed in section II.A., above, EPA regulations effectively establish a “rebuttable 

presumption” that “fishable/swimmable” uses are attainable and therefore should apply to a 

water body unless it is affirmatively demonstrated that such uses are not attainable. EPA 

adopted this approach in order to help achieve the national goal articulated by Congress that, 

“wherever attainable,” water quality provide for the “protection and propagation of fish, 

shellfish and wildlife” and for “recreation in and on the water.” CWA 101(a). While facilitating 

achievement of Congress’ goals, the “rebuttable presumption” approach preserves States’ 

paramount role in establishing water quality standards in weighing any available evidence 

regarding the attainable uses of a particular water body. The rebuttable presumption approach 

does not restrict the discretion that States have to determine that “fishable/ swimmable” uses 

are not, in fact, attainable in a particular case. Rather, if the water quality goals articulated by 

Congress are not to be met in a particular water body, the regulations simply require that such a 

determination be based upon a credible, “structured scientific assessment” of use attainability.... 

63 FR 10799, 10800, March 5, 1998. See also 67 FR 65256, 65258, October 23, 2002.

In 2003, EPA promulgated a primary contact recreation designated use in Kansas for 1,056 waters, a 

secondary contact recreation designated use for 230 waters, and an aquatic life designated use for one 

water body to replace non-101(a)(2) use designations that EPA had previously disapproved. The 

preamble to the final rule included similar text to the Alabama preambles quoted above. See 68 FR 

40428, 40430 (July 7, 2003). 

In 2004, EPA promulgated a primary contact recreation designated use for coastal waters in Puerto Rico

to replace a Class SC designated use that included only secondary contact recreation. EPA took the 

action in response to a court order that found that an EPA Region 2 letter to the territory constituted a 

section 303(c)(4)(B) Administrator’s determination that federal standards were necessary. The preamble 

included similar text to the Alabama preamble text quoted above. See 69 FR 3514, 3516 (January 26, 

2004). 

Therefore, it is clear that interpretation originates from EPA’s 1983 regulations effectively establishing a 

rebuttable presumption approach and EPA has consistently applied this interpretation in its own 

promulgations. It is important to note that the EPA’s regulation does not actually establish any 

designated uses effective for CWA purposes in and of itself. Rather, the regulations serve as the baseline 

goal use that the state or authorized tribe starts from consistent with 303(c)(2)(A) and 101(a)(2). States 

and authorized tribes must either adopt the uses specified in CWA section 101(a)(2) or rebut the 

presumption that such uses are attainable in one or more of the situations described in section

131.10(g). However, the applicable WQS are always those standards adopted by the states or authorized 

tribes and approved by EPA or those WQS promulgated by EPA for a state or authorized tribe. See 

40 CFR 131.21(c) and (e). Please see also subsection B of this essay for additional discussion.

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A few commenters cited to National Wildlife Federation v. Gorsuch, 693 F.2d 156, 178 (D.C. Cir 1982) 

that upheld EPA’s interpretation that dams are not required to obtain CWA section 402 permits. The 

commenters quoted language from the decision providing that “[a]s any student of the legislative 

process soon learns, it is one thing for Congress to announce a grand goal, and quite another for it to 

mandate full implementation of that goal. Read as a whole the Clean Water Act shows not only 

Congress’ determined effort to clean up our polluted lakes and rivers, but also its practical recognition of 

the economic, technological, and political limits on total elimination of all pollution from all sources. . . . 

Caution is always advisable in relying on a general declaration of purpose to alter the apparent meaning 

of a specific provision.” First, commenters ignored key statements that provide context for these 

quotes: 

Undeniably, Congress’ strong statement of its objective must color EPA’s and our interpretation 

of specific provisions of the Act. But, as any student of the legislative process soon learns, it is 

one thing for Congress to announce a grand goal, and quite another for it to mandate full 

implementation of that goal. Read as a whole, the Clean Water Act shows not only Congress’ 

determined effort to clean up our polluted lakes and rivers, but also its practical recognition of 

the economic, technological, and political limits on total elimination of all pollution from all 

sources. The Act contains numerous requirements that cost be taken into account in 

establishing effluent limits, as well as assorted exemptions from those limits. Moreover, the 

purposes section, in its own right, suggests that Congress recognized that the substantive 

provisions of the Act fall short of completely achieving the announced goals of the Act. Congress 

hedged the purposes section by making it apply only as “consistent with the provisions of this 

[Act],” and explicitly distinguished between the congressional “policy” to eliminate discharge of 

toxic pollutants and the presumably weaker “goal” of eliminating discharge of all pollutants.

Id. The court’s opinion makes clear that it was only considering the sole issue of “whether certain daminduced water quality changes constitute a ‘discharge of a pollutant’ as that term is defined in 502(12) 

of the Act” and did not consider the specific provision at issue in this rulemaking, section 303(c)(2)(A), 

that explicitly directs that WQS shall serve the purposes of the Act. Id. at 162. Importantly, D.C. Circuit

determined that the lower court had failed to give enough deference to EPA’s construction of the Act, 

characterized its decision as “narrow” and held that EPA’s interpretation is both reasonable and entitled 

to great deference. Id. at 162, 183. Finally, the court in Idaho Mining considered this case and noted that 

plaintiff’s reliance on this case “ignores section 303(c)(2)(A) of the CWA which expressly provides that 

water quality standards must be established taking into consideration the purposes of the Act.” Idaho 

Mining, 90 F.Supp.2d at 1098.

Commenters pointed to specific statements from the legislative history relating to section 101 to 

support their argument that the goal is merely aspirational, not a requirement. EPA acknowledges that 

the goals and objectives of the Act were vigorously debated and discussed in the legislative history but 

the resulting statute retaining the objective and goals provides evidence that Congress intended these 

goals to serve essential purposes in implementing the Act, and in particular implementing 303(c)(2)(A) 

which explicitly links the “purposes” of the Act to WQS. It is evident from the quote cited by the 

commenters that the focus of that particular Senator’s comments relate to the goal in 101(a)(1), which 

focuses on eliminating the discharge of pollutants by 1985, not the goal in 101(a)(2). In addition, the 

quote makes clear that the Senator’s comments were also focused on the relevant timetables as not 

being “an absolute requirement to be fully implemented as of a magic date.” 

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Another commenter focused on a discussion in the legislative history addressing the language used in 

the statute regarding goals and policies. That discussion appears to be focusing on the no discharge goal, 

not the interim goal or section 303(c)(2)(A) at issue here. 

Finally, commenters included citations and discussions of cases involving rebuttable presumptions to 

support an argument that to the extent EPA’s regulations establish a rebuttable presumption, such a 

rebuttable presumption is inconsistent with case law. EPA disagrees with these comments and notes 

that similar arguments were raised in the Idaho Mining litigation and there EPA explained that: 

..the ‘presumption’ used by EPA was not of the evidentiary sort in which “Fact 1 implies Fact 2.” 

Rather administrative agencies, including EPA, commonly adopt regulatory schemes that set 

forth requirements for avoiding or obtaining a given regulatory outcome (citations 

omitted)...EPA’s presumption established the baseline regulatory outcome that would apply 

absent sufficient evidence to the contrary. Under the Clean Water Act, there needs to be some 

standard against which EPA judges the adequacy of designated uses. EPA’s regulations are, at 

least, a reasonable choice within the range of possible options.

EPA Op. Br. 23. EPA also noted in its reply brief that the rebuttable presumption at issue here involves 

statutory interpretations governed by Chevron. EPA Reply. Br. 8-9. 

The court in Idaho Mining agreed:

Plaintiff argues that even if the EPA did have statutory authority to adopt the rebuttable 

presumption at issue, the EPA exceeded that authority when it applied the presumption in this 

case. Specifically, Plaintiff asserts that the presumption was unlawful because there was no 

sound factual connection between the facts giving rise to the presumption and the presumed 

facts. Furthermore Plaintiff contends that there was no meaningful opportunity to rebut the 

presumption. Thus, Plaintiff argues that the EPA’s presumptive use interpretation cannot stand.

With respect to its first assertion, Plaintiff primarily relies on Holland Livestock Ranch v. U.S.,

714 F.2d 90, 92 (9th Cir.1983), for the proposition that an agency presumption is not valid unless 

a “ ‘sound factual connection’ exists between the facts giving rise to the presumption and the 

facts then presumed.” Plaintiff argues that in this case, that “sound factual connection” is totally 

lacking. Specifically, Plaintiff contends that the EPA’s aquatic life use presumption is premised 

on nothing more than a “finding that where there is surface water then aquatic life uses are 

attainable.” (IMA’s Memorandum in Support of Motion for Summary Judgment, Docket # 17, 

p. 17) (footnote omitted). Plaintiff again argues that the EPA created the presumption merely as 

a means of avoiding its obligation to conduct the required analyses to support the aquatic life 

use designation. Thus, Plaintiff submits that the presumption is ultra vires and should be 

invalidated by this Court. See Holland Livestock, 714 F.2d at 92 (“Administrative presumptions 

should not replace proof needlessly.”); Atchison, Topeka & Santa Fe Ry. Co. v. ICC, 580 F.2d 623, 

629 (D.C.Cir.1978) (“The Commission is not free, as the legislature may be, to formulate a 

presumption that derives rationality from policy considerations of its own choosing ....”); Pacific 

Gas, 506 F.2d at 38-39 (“An agency cannot escape its responsibility to present evidence and 

reasoning supporting its substantive rules by announcing binding precedent in the form of a 

general statement of policy.”).

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In response, Defendants argue that Plaintiff’s reliance on Holland Livestock, etc. is misplaced. As 

Defendants point out, most of the cases cited by Plaintiff involve evidentiary presumptions 

rather than regulatory presumptions such as the presumption relied upon by the EPA in this 

case. Defendants argue that the rebuttable presumption of fishable/swimmable attainability is 

not the sort of presumption in which one fact implies the other. Rather, Defendants contend 

that the rebuttable presumption it is a regulatory scheme designed to obtain or avoid a 

particular regulatory outcome. Defendants cite several cases in which such regulatory 

presumptions have been upheld. See e.g., Downer v. United States ex rel. Dept. of Agriculture,

97 F.3d 999, 1005 (8th Cir.1996); Bersani v. Robichaud, 850 F.2d 36, 39 (2d Cir.1988). 

Furthermore, Defendants maintain that the rebuttable presumption is merely an interpretation 

of existing regulations and that the Court’s analysis should therefore by guided by Chevron, 

supra.

Again, the Court agrees with Defendants’ position as to this issue. Contrary to Plaintiff’s 

assertions, the rebuttable presumption on which the EPA relied in promulgating the challenged 

rule was not a new or novel regulatory requirement created by the EPA specifically for the 

purposes of the 1997 rulemaking. In fact, as has been previously discussed, the EPA actually 

adopted the rebuttable presumption in favor of fishable/swimmable uses in 1983 with the 

promulgation of its regulations at 40 C.F.R. § 131.10(j) and (k). See discussion at Section II.A.1., 

supra. Thus, unlike the presumptions in the cases cited by Plaintiff, the rebuttable presumption 

in this case came about as a direct result of the EPA’s statutory authority to develop rules that 

reasonably implement the CWA. Furthermore, the rebuttable presumption of 

fishable/swimmable attainability is not, as Plaintiff contends, an evidentiary presumption that 

replaces proof needlessly; for individual states are always given the opportunity to submit 

evidence in the form of a UAA demonstrating that a particular water body is not capable of 

attaining fishable/swimmable uses. Cf. Holland Livestock, 714 F.2d at 92 (invalidating agency 

presumption, that cattle with unrestricted access to public lands have in fact trespassed on the 

public lands, where agency attempted to use the presumption as the sole evidence to establish 

a claim of trespass). Rather, it is an interpretive rule designed to further the policies of the CWA 

by providing for fishable/swimmable use designations unless a UAA affirmatively demonstrates 

that such uses cannot be attained. Insofar as the rule represents a permissible construction of 

the CWA and a reasonable accommodation of the conflicting policies contained therein, the 

EPA’s statutory interpretation is entitled to deference from this Court. Chevron, 467 U.S. at 

844-45, 104 S.Ct. at 2782-83. 

90 F. Supp.20 at 1098-99. The commenters argue that the number of total maximum daily loads (TMDLs) 

in effect undermines the reasonableness of applying the regulations as a rebuttable presumption. EPA 

disagrees as TMDLs represent just a portion of the water subject to the CWA. More importantly, states 

and authorized tribes have long operated under the 1983 requirements that identify the uses specified 

in section 101(a)(2) of the Act as a starting place but allow states and authorized tribes to adopt other 

uses if it demonstrate the uses specified in section 101(a)(2) (or subcategories of such uses) are not 

attainable. The regulations allow states and authorized tribes the discretion to weigh evidence relevant 

to whether uses specified in section 101(a)(2) of the Act or subcategories of such uses are attainable in a 

particular case. As discussed above, EPA’s long standing view is that such an approach of starting with 

the uses specified in section 101(a)(2) of the Act instead of a blank slate is a more effective way of 

ensuring that WQS are consistent with 303(c)(2)(A) and the directive that WQS shall serve the purposes 

of the Act.

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As evidenced from the discussion above, EPA has previously addressed questions, like those raised by 

commenters today, relating to its authority for its regulations and interpretation regarding the

rebuttable presumption. Consistent with its prior position, EPA disagrees with comments challenging its 

authority. 

In addition, EPA disagrees with the commenter who took the position that Idaho Mining case was 

wrongly decided consistent with the discussions above. EPA notes that commenter is incorrect in stating 

that the court in Idaho Mining did not address EPA’s regulations and interpretation as well as its specific 

action in Idaho. The commenter also incorrectly states that the decision did not “contemplate or 

support the blanket application of a rebuttable presumption to all waters of the United States, as EPA is 

attempting in this rulemaking,” and cites to the unreported decision in Associated Indus. of Alabama v. 

Train, 9 ERC 1561 (N.D. Ala. 1976). The court in Idaho Mining did, in fact, address this issue and case 

specifically:

Defendants argue that the Train case is also distinguishable from the case at bar because the 

Train court never addressed the EPA’s authority to establish federal use designations under the 

current statute. Specifically, Defendant directs the Court’s attention to those provisions of the 

current CWA which provide that water quality standards should be such as to serve the 

purposes of the Act, including the achievement of fishable/swimmable uses wherever those 

uses are attainable. See 33 U.S.C. §§ 1251(a)(2) and 1313(c)(2)(A). Furthermore, Defendants 

argue that the Train case is inapplicable here because the “fish and wildlife” use designation at 

issue in that case was a “blanket minimum” designation and was, therefore, actually an 

irrebuttable presumption. Finally, Defendant argues that the analyses employed by the court in 

Train is inadequate in light of subsequent decisions, such as the Supreme Court’s decision in 

Chevron, supra, which specifically address the appropriate standard to be employed when 

reviewing an agency’s interpretation of a statute which it administers. The Court agrees.

Idaho Mining, 90 F.Supp.2d at1095-99.

The commenter goes on to argue that “[t]he primary question left unresolved by this decision is, if 

Congress did in fact intend for such a blanket presumption to exist for all waters of the United States, 

why did it not explicitly set it out in the CWA.” The Idaho Mining court acknowledged this void. Idaho 

Mining., 90 F. Supp. 2d at 1088 (providing that “the CWA does not itself create a rebuttable 

presumption that [fishable and swimmable] uses are always attainable”). As discussed above, the court 

clearly addressed this issue when it found that “[f]urthermore, although the CWA does not require 

fishable/swimmable use designations for all waters of the United States, the EPA clearly acted within the 

bounds of its statutory authority in creating the presumption to further the mandatory goals and 

purposes of the Act.” Id. at 1107. Therefore, EPA disagrees that the court in Idaho Mining left these 

issues unresolved.

Commenters cite to section 302(b) as being relevant to today’s rule. While this section is outside the 

scope of this rulemaking, EPA notes that its longstanding interpretation of this provision applies to the 

adoption of effluent limitations more stringent than necessary to meet WQS.

One commenter argues if Congress believed that all waters must be designated for uses specified in 

section 101(a)(2) of the Act that such uses would have been in place in 1972. EPA’s requirements have 

changed over the years but the UAA requirement has existed in its current form since 1983. See 

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preamble to 1982 proposed and 1983 final preambles (47 FR 9234, October 29, 1982; 48 FR 51400, 

November 8, 1983.) 

EPA received comments that EPA’s rebuttable presumption has or will result in National Pollutant 

Discharge Elimination System (NPDES) permits and TMDLs based on WQS that a water body is not 

capable of meeting. As discussed in this essay, rebutting the presumption of attainability is a pre-existing 

requirement stemming from the 1983 regulations that remain fundamentally unchanged by today’s 

rule. To the extent the commenters are making assertions about the past, such claims are unsupported 

by the comments. To the extent the commenters are making assertions about the future, such claims 

are speculative. As such, these comments are outside the scope of this rule, and do not require EPA 

response. States and authorized tribes continue to have the discretion to demonstrate that the uses 

specified in CWA section 101(a)(2) are unattainable or, as an alternative, to maintain their WQS to serve 

the 101(a)(2) goal and objective of the CWA.

B. Other Comments Related to the Rebuttable Presumption Approach in EPA’s 

Regulations

EPA has long explained that its regulations that effectively establish a rebuttable presumption approach 

are an essential foundation for effective implementation of the CWA as a whole. EPA’s 1998 Advance 

Notice of Proposed Rulemaking (ANPRM) explained that “[t]his approach preserves States’ and 

[authorized] Tribes’ paramount role in establishing water quality standards, in this instance, in weighing 

any available evidence regarding the attainable uses of a particular water body. The rebuttable 

presumption approach does not restrict the discretion that States and Tribes have to determine that 

“fishable/swimmable” uses are not, in fact, attainable in a particular case. Rather, if the water quality 

goals articulated by Congress are not to be met in a particular water body, the regulations simply 

require that such a determination be based upon a credible, “structured scientific assessment” of use 

attainability.” (63 FR 36749, July 7, 1998).

EPA disagrees with comments that the rebuttable presumption concept creates a “de facto” use 

designation. As discussed above, the regulations do not require states and authorized tribes to

necessarily adopt the uses specified in section 101(a)(2) of the Act for all waters of the U.S., nor does it 

automatically designate the uses specified in section 101(a)(2) of the Act for all waters of the U.S. in the 

absence of state or tribal action. Rather, it presumes that such uses are attainable unless demonstrated 

to be unattainable, per EPA’s regulations. EPA disagrees with the commenter that EPA’s regulations limit 

states’ and authorized tribes’ ability to revise use designations related to the uses specified in section 

101(a)(2) of the Act even when, as the commenter asserts, were adopted with “insufficient 

information.” EPA’s prior existing regulations provide a reasonable avenue for removing those uses that 

are demonstrated to be unattainable.

C. Comments on Burden

In response to commenters that contend that “a presumption of this kind, if promulgated, would place a 

significant additional burden on States,” EPA notes that is has not changed the requirements relating to 

what a state or authorized tribe must do when conducting a UAA, including a demonstration that it is 

not feasible to attain a use specified in section 101(a)(2) of the Act due to one of the regulatory factors.

All of those requirements remain unchanged by today’s rule. Therefore, there is no incremental burden 

associated with this rulemaking related to the “presumption of this kind.” 

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EPA generally disagrees with commenters who stated that the rebuttable presumption is always difficult 

to overcome, and that it places a large burden on state resources by creating a de facto use designation 

that the CWA 101(a)(2) uses are attainable unless demonstrated otherwise through a UAA. As discussed 

in subsection B of this essay, the rebuttable presumption does not actually create a de facto use 

designation that is automatically applicable. Rather, it is a basis for state/tribal WQS actions or EPA 

promulgations. EPA has approved designated use changes based on UAAs that range from simple to 

complex. Whether a UAA will be simple or complex will vary on a case-by-case basis based on a number 

of factors, such as the type of water body involved, the size of the segment(s) and/or the number of 

water bodies involved (if doing a categorical UAA), the characteristics of the water body, the designated 

use being changed and the relative degree of change, the factual showing needed to make a 

demonstration that attaining the designated use is not feasible using one or more of the factors 

specified in section 131.10(g), the level of public interest/involvement in the designated use decision, 

etc. A discussion of some examples displaying the various spectrum of UAAs is available at 

http://water.epa.gov/scitech/swguidance/standards/uses/uaa/index.cfm. For discussion regarding cost 

burden due to the final rule, see EPA’s economic analysis (EA) final rule (which did not analyze cost or 

burden associated with the rebuttable presumption approach in general because, as discussed above,

regulations that effectively create the presumption have existed since 1983, and thus any cost or burden 

related to it is not attributable to this final rule). See also response essay 12.a for a discussion on costs 

and burden of the final rule. 

D. Comments on Link to Use Attainability Analyses and Total Maximum Daily 

Loads

Some commenters contend that UAAs should be conducted prior to adopting any of the uses specified 

in section 101(a)(2) of the Act. In finalizing its 1983 requirements, EPA rejected this approach of 

requiring the state to affirmatively demonstrate that the uses specified in 101(a)(2) of the Act are 

attainable and instead codified 40 CFR section 131.10(k), which provides that a state or authorized tribe 

may forgo a UAA if it includes the section 101(a)(2) goal uses in its use designations. EPA determined 

that such an approach is consistent with section 510. See 48 Fed. Reg. at 51,401. In response to the 

commenters who suggest that EPA encourage or require states and authorized tribes to review the 

attainability of designated uses before a TMDL is developed and adopted, EPA does not agree or 

disagree and notes that TMDL processes may be coordinated with use refinement processes before, 

during or after a TMDL is conducted. The timing of such coordination is at the discretion of the state or 

authorized tribe. For additional discussion on these specific issues, please see response essay 5.j.

EPA disagrees with comments that the regulation will no longer require states and authorized tribes to 

justify an upgrade to a use specified in section 101(a)(2) designated use. The regulation never required 

states and authorized tribes to conduct a UAA when “upgrading” to a use specified in section 101(a)(2). 

The regulation is established to ensure that states and authorized tribes are evaluating attainability of 

the uses specified in CWA section 101(a)(2) before adopting uses other than uses specified in section 

101(a)(2)) or uses that do not protect the uses specified in section 101(a)(2) of the Act. Once a UAA is 

done and demonstrates that such uses are not attainable under today’s rules the state or authorized 

tribe must adopt the highest attainable use (HAU) as defined in section 131.3(m). During the triennial 

review process, section 131.20(a) ensures that states and authorized tribes are reevaluating the 

attainability of such waters at least once every three years through a public hearing process to 

determine whether new information has become available to indicate that the uses specified in section 

101(a)(2) of the Act are attainable and, if so, upgrade their uses accordingly. However, when upgrading a 

designated use to a use specified in section 101(a)(2), a UAA is not required in the final rule as specified 

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in section 131.10(k)(2). If uses specified in section 101(a)(2) of the Act are not fully attainable, then 

under EPA’s prior existing regulations, a state or authorized tribe must upgrade its uses to protect what 

is presently being attained. See 40 CFR 131.10(i). For additional discussion on this specific issue, please 

see response essay 5.c.

E. Comments on Hierarchy Created by Rebuttable Presumption

EPA generally disagrees with the comment that the rebuttable presumption is, in effect, creating 

“preferred” (i.e., the uses specified in section 101(a)(2) of the Act that are presumed attainable) and 

“non-preferred” (i.e., non-101(a)(2)) uses. The CWA itself specifically calls for the protection and 

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

uses) as the national goal, wherever attainable; however, this does not mean that non-101(a)(2) uses 

are not important or ever appropriate, nor does it mean that non-101(a)(2) uses may be removed 

without adequate documentation or public process (consistent with CWA requirements, specifically 

section 131.10(a)). The final rule makes revisions to section 131.10(a) to explicitly require a state or 

authorized tribe to submit documentation justifying how its consideration of the use and value of water 

for those uses listed in section 131.10(a) (which include both the uses specified in section 101(a)(2) of 

the Act, as well as non 101(a)(2) uses) appropriately supports the state’s or authorized tribe’s action to 

remove any of those uses. For additional discussion on this issue, please see response essays 5.k. and 

5.h.

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Essay 5.j. – Designated Uses: General Comments

A. Reviewing the Attainability of Uses

The U.S. Environmental Protection Agency (EPA) acknowledges several commenters’ suggestions that 

EPA encourage or require states and authorized tribes to review the attainability of designated uses 

before a total maximum daily load (TMDL) is established. States and authorized tribes may coordinate 

their TMDL processes with their designated use refinement process before, during, or after a TMDL is 

established. The timing of such coordination is at the discretion of the state or authorized tribe. It is

important, however, that the information collected is shared, as the stakeholder process and analyses 

used for a use attainability analysis (UAA) and the development of a TMDL can play a large role in 

informing each other. See essay 5.i for further discussion.

To effectively make use of the resources dedicated to these processes, states and authorized tribes 

should consider evaluating the attainability of their designated uses during the TMDL development 

process. Such an approach may have a number of benefits. By designating a use known to ultimately be 

attainable for an impaired waterbody (and associated scientifically sound criteria to protect that use), a 

state or authorized tribe can develop TMDLs using the most appropriate targets. TMDLs developed to 

meet appropriate water quality standards (WQS) will result in the development of appropriate waste 

load allocations for point sources and load allocations for nonpoint sources (NPS). These allocations will, 

in most cases, ultimately affect proposed controls. In addition, the information gathered to develop a 

TMDL, and the allocations in a TMDL, may point to the need for a designated use change (and possibly 

a UAA).

In addition to ensuring appropriate targets, coordinating the designated use refinement and TMDL 

development processes may allow for a more collaborative approach where states/authorized tribes 

and stakeholders can discuss issues that may influence both processes. This method provides a forum 

for affected parties, who may be the same for both processes, to discuss the ways in which to best 

identify and achieve appropriate WQS and meet local needs. This approach may be particularly helpful 

where a UAA can assist in finding other unknown causes or sources of impairment. Finally, with a 

collaborative approach, states and authorized tribes can evaluate designated uses and develop TMDLs in 

a coordinated fashion to spur cross-program information exchange (e.g., water quality data, formulation 

of multi-stakeholder teams and workgroups). This approach may also yield a current and historical 

assessment of the effectiveness of modeling tools, best management practices (BMPs), resources, and 

partnerships. A coordinated process may also allow a state or authorized tribe to combine public 

participation requirements for establishing a TMDL and revising a state/tribal WQS, as needed.

As mentioned earlier, states and authorized tribes have discretion to determine whether to do the 

designated use refinement and TMDL development processes sequentially or simultaneously. If a state 

or authorized tribe chooses to do them sequentially, there are a number of factors that it may want to 

consider in determining the order. In particular, it is important for states and authorized tribes to 

consider the time needed to adopt revised WQS should a use re-designation be appropriate. Many 

state/authorized tribal regulation adoption processes can take two to three years to effect a change. 

Depending on TMDL-development schedule, a state or authorized tribe may not have the flexibility to 

wait several years to finalize a TMDL. However, if a UAA is completed after a TMDL is finalized, the TMDL 

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may need to be revised to reflect the newly refined use. States and authorized tribes should consider 

ways to reduce the overall workload when determining the appropriate sequence.

For discussion relating to the definition of existing uses and a response to comments that states and 

authorized tribes should evaluate the attainability of existing uses, please see response essay 5.d.

EPA disagrees with the comment that UAAs should be conducted prior to adopting any of the uses 

specified in section 101(a)(2) of the Act. For a response to this comment, please see the response essay 

5.i about the “rebuttable presumption.” See also comment response essay 5.h.

EPA acknowledges the comment that it should encourage or require states and authorized tribes to 

review the attainability of designated uses during the triennial review of WQS. EPA’s prior existing 

regulations at 131.20(a) provided that for “[a]ny water body segment with water quality standards that 

do not include the uses specified in section 101(a)(2) of the Act shall be re-examined every three years 

to determine if any new information has become available. If such new information indicates that the 

uses specified in section 101(a)(2) of the Act are attainable, the State shall revise its standards 

accordingly.” In the preamble to the proposed rule, EPA “recommends that states and tribes consider 

the HAU during a triennial review. If new information becomes available during a triennial review to 

indicate that a use higher than what is currently designated is attainable, states and tribes should revise 

their WQS to reflect the HAU” (78 FR 54524). EPA considered requiring states and authorized tribes to 

always adopt the highest attainable use (HAU) in section 131.20(a) as part of their triennial review 

process; however, in an effort to limit the burden on states and authorized tribes EPA instead limited 

the HAU requirement to only instances where a UAA is required per section 131.10(j). EPA does not 

believe such a provision is counter to the goals of the Clean Water Act (CWA) because EPA’s regulation 

at section 131.10(i) also requires that “where existing water quality standards specify designated uses 

less than those which are presently being attained, the State shall revise its standards to reflect the uses 

actually being attained.” Title 40 of the Code of Federal Regulations (CFR) section 131.20(a) clearly 

requires states and authorized tribes to revise their WQS in instances where new information indicates 

that uses specified in section 101(a)(2) of the Act are attainable; therefore, EPA does not view the word 

“should” as being in conflict. For additional discussion in triennial review, please see response essay 6.g.

B. Flexibilities

Multiple commenters suggested that EPA provide greater flexibility in the context of designating uses 

and assessing use attainability, to account for location-specific characteristics (e.g., arid states with a 

large number of intermittent or ephemeral streams).

EPA agrees with the comments that states and authorized tribes should have flexibility in methods used 

to evaluate attainability of designated uses. While EPA’s regulations provide specialized requirements 

for uses specified in section 101(a)(2) of the Act and subcategories of such uses, including the 

requirement to demonstrate that such a use is not feasible because of one of the six regulatory factors, 

there are other WQS mechanisms available that may allow a state or authorized tribe to deal with 

pollutant specific or location specific challenges to attainability more effectively than revising or 

removing a designated use. Such mechanisms include adopting a WQS variance and/or establishing sitespecific criteria. Where a designated use cannot be attained immediately but there is no uncertainty 

around the ultimate attainability of the designated use, permit compliance schedules (CS) may be the 

most appropriate mechanism to give dischargers time to come into compliance with their permit 

requirements. In addition to these mechanisms and in response to comments, to streamline a state’s or 

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authorized tribe’s efforts to designate more accurate uses, the state or authorized tribe may conduct a 

categorical UAA if it can identify multiple waters or waterbody segments with similar characteristics and 

constraints on attainability. This efficient approach may reduce regulatory and process burden by 

allowing the state or authorized tribe to involve its public in one effort that uses a single analysis to 

represent many sites. To use such an approach, however, it is critical to have enough information about 

each particular site to reliably place it into the category. The public is an integral resource for obtaining 

sufficient information to reliably include waters in the categorical UAA. Such information can be 

obtained from the public during the public hearing process as well as the triennial review process or any 

other process the state or authorized tribe establishes to obtain public feedback.

EPA agrees with comments stating that the degree of analysis necessary when showing that a 

designated use is, or is not, attainable may vary based on the characteristics of different waterbodies 

and, in some situations. In addition, whether a UAA and/or associated new or revised WQS can be 

“expedited” is likely to depend upon a particular state’s or authorized tribe’s administrative process. As 

discussed earlier, in some situations, a categorical UAA may be appropriate and may streamline the 

administrative process enough that use revisions can be adopted and approved quicker than if the state 

or authorized tribe conducts a separate UAA for each water body or waterbody segment and adopts 

each individual use change in separate actions. In regards to the degree of analysis, EPA emphasizes that 

a UAA is defined under EPA’s regulations as a “structured scientific assessment” and therefore must 

provide an adequate scientific and technical rationale in the administrative record to support the 

resulting designated use change consistent with CWA requirements and EPA regulations. States and 

authorized tribes may use state/tribal/regional-specific guidance documents, a certain protocol, or 

standard operating procedures (SOPs) when conducting the UAAs. Regardless of the methods used, 

EPA’s review is based upon whether the ultimate WQS revision meets the requirements of the CWA and 

federal regulations. EPA has approved designated use changes supported by UAAs that range from 

simple to complex. Whether the UAA will be simple or complex will vary on a case-by-case basis based 

on a number of factors, such as the type of water body involved, the size of the segment(s) or the 

number of water bodies involved (if doing a categorical UAA), the characteristics of the water body, the 

designated use being changed and the relative degree of change, the factual showing required to make 

a demonstration that attaining the designated use is not feasible using one or more of the factors 

specified in section 131.10(g), the level of public interest/involvement in the designated use decision, 

etc. A discussion of some examples displaying the varying spectrum of UAAs is available at 

http://water.epa.gov/scitech/swguidance/standards/uses/uaa/index.cfm. 

C. Use Attainability Analyses and Section 131.10(g) Factors

While EPA agrees that UAAs should not be required when states and authorized tribes adopt new or 

revised non-101(a)(2) uses, EPA disagrees with the commenter that a UAA should not be required when 

a state or authorized tribe is adopting new or revised designated uses that are “less” than the uses 

specified in CWA section 101(a)(2) (i.e., subcategories of uses specified in section 101(a)(2) of the Act). 

Please see response essay 5.h. for additional discussion about non-101(a)(2) uses. EPA disagrees that 

states and authorized tribes should be allowed to use their discretion to determine when a UAA is 

necessary in all cases. The commenter suggests that perhaps UAAs could be reserved for large, 

important water bodies or for waters with low flow. EPA acknowledges that the analysis included in a 

UAA may vary depending on the waterbody and the relevant attainability issues, but changing the 

regulations in such a way would be overly complex and difficult for states and authorized tribes to 

implement. In addition, EPA’s prior existing regulations allowed states and authorized tribes to address 

low flow issues in certain circumstances. See 131.10(g). That said, EPA disagrees that states and 

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authorized tribes should be able to avoid a UAA all together and not have to consider the attainability of 

the use consistent with EPA’s regulations. As discussed in essay 5.g, EPA’s final rule revisions to 

131.10(j), which specifies when a UAA is required, were refinements and are consistent with the 1983 

requirements and EPA’s implementation of those requirements. Please see response essay 5.g. for a 

thorough discussion of how section 131.10(j) and (k) continues to implement the CWA in the same way 

that was intended when the 1983 WQS regulations were adopted. Allowing states and authorized tribes 

full discretion to determine when a UAA is or is not required would be inconsistent with the intent of 

EPA’s implementing regulations to ensure that states’ and authorized tribes WQS continue to serve the 

water quality goal in section 101(a)(2) of the Act wherever attainable, because states and authorized 

tribes would not necessarily evaluate attainability before removing a designated use and could thus 

remove an attainable use resulting moving water quality away from the CWA objectives.

EPA agrees with the commenter who understands the final rule as requiring states and authorized tribes 

to conduct a UAA for any water body that does not protect humans when consuming aquatic organisms, 

consistent with EPA’s interpretation of CWA sections 101(a)(2) and 303(c)(2)(A). Please see response 

essay 5.k. for additional discussion on the legal rationale for EPA’s interpretation. If a state or authorized 

tribe wishes to demonstrate that a waterbody segment designated for aquatic life cannot attain fish or 

shellfish consumption and therefore does not require human health criteria to protect for such 

consumption, then it must conduct a UAA and meet the requirements of section 131.10. If the state or 

authorized tribe pursues removing protection for humans when consuming aquatic life, the UAA must 

demonstrate why it is infeasible to attain such a designated use based on one or more of the factors at 

section 131.10(g). If the state or authorized tribe adopts new or revised WQS based on this UAA, it 

would also have to identify and adopt the HAU in its place, consistent with section 131.10(g). It is 

important to note that if a state or authorized tribe believes that the designated use should be removed 

because there are no aquatic organisms present in the water that are consumed by humans, it must 

describe how it determined what it considers to be consumable aquatic organisms and why when 

demonstrating that such a use is not attainable.

EPA agrees with the comment that the factors at section 131.10(g) are not directly applicable to 

whether individuals or members of the pubic consume certain aquatic organisms. The factors at 

131.10(g) relate to whether consumption of organisms is attainable. For example, if a state or 

authorized tribe believes that consumption of organisms is not attainable because there is no 

consumable aquatic life in the water, it may be able to demonstrate that the use is not attainable based 

on, for example, 131.10(g)(5) because physical factors preclude such aquatic organisms from being in 

the water body.

EPA agrees that it is important for EPA regional offices to work with states and authorized tribes on the 

development of UAAs, but disagrees with the comment that UAAs may slow down or stop the process of 

evaluating beneficial uses. EPA encourages states and authorized tribes to work with their appropriate 

EPA Regional office, as needed, regarding uses and UAAs before submitting the WQS revision and the 

UAA. EPA can provide early assistance in determining existing uses and address any policy and technical 

questions that may arise. Early collaboration between states and authorized tribes and EPA Regional 

representatives will significantly facilitate the UAA and WQS review processes. Therefore, it is important 

for the state or authorized tribe to send EPA the draft UAA before any WQS revisions are proposed. An 

even more effective approach would be to engage EPA during the development of a UAA protocol, 

guidance, or standards operating procedures (SOPs) and to exchange information at the beginning, 

rather than the end, of the UAA process. There have been many such successful coordination efforts 

since EPA sent its March 2006 memorandum to the EPA Water Division Directors entitled “Improving 

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the Effectiveness of the Use Attainability Analysis (UAA) Process.” For additional discussion on the 

economic impact of UAAs, see response essay 12.b.

EPA disagrees with the comment that indicates that states and EPA Regions are “not developing or 

approving UAAs”, despite the existence of the March 2006 memorandum. The commenter did not 

provide any specific data regarding the failure of states and EPA Regions to develop and/or approve 

UAAs for EPA to respond to. However, EPA notes that it does not and would not force a state or 

authorized tribe to conduct a UAA and downgrade its 101(a)(2) designated uses (consistent with CWA 

section 510). Such a decision is at the discretion of the state or authorized tribe, as long as its actions 

satisfy minimum CWA and federal requirements. Where states and authorized tribes submit a 

designated use revision based on a UAA, EPA must approve or disapprove it in a timely manner. EPA can 

only approve a use change if it meets the requirements of the CWA, and EPA’s implementing regulation.

EPA received comment on the topic of designating uses where there is a “tributary rule” in place. Some 

states and authorized tribes have regulations, often preceding EPA’s 1983 WQS regulations, which allow 

the state or authorized tribe to apply the designated use of a larger downstream water to its smaller 

upstream unclassified tributaries. This is often used where a state or authorized tribe does not 

specifically name very small waters in their WQS but covers them in their WQS by applying a blanket 

“general default” set of WQS (usually with narrative protections). For example, if downstream “River Z” 

is designated for primary contact recreation, the state or authorized tribe would use the designation 

from “River Z” for any CWA implementation purposes on these small tributaries. States and tribes often 

refer to such a regulation as a “tributary rule.” However, using a tributary rule does not actually 

designate the use for those upstream tributaries. EPA generally expects that the tributary rule is used on 

smaller waters where there are no permitted point source discharges and that if such a discharger 

becomes permitted, the state or authorized tribe will specifically designate uses for that tributary, 

consistent with EPA’s regulations at section 131.10. EPA agrees with the commenter that where a state 

or authorized tribe is designating a specific use for a water body rather than continuing to rely on 

protection from a “tributary rule,” then this situation is considered designating a use “for a waterbody 

for the first time” as specified in section 131.10(j). In this instance, section 131.10(j) would specify that a 

UAA must be conducted whenever “The State designates for the first time ...uses that do not include the 

uses specified in section 101(a)(2) of the Act.” This is reasonable because where the upstream tributary 

is being protected for a subcategory of a use specified in section 101(a)(2) of the Act because that is the 

designation of the downstream water, the presumption was never rebutted for the tributary itself. 

Therefore, the state or authorized tribe must rebut the presumption and demonstrate that the uses 

specified in CWA section 101(a)(2) are not attainable before designating anything less than the uses 

specified in CWA section 101(a)(2). Where the designated use of the downstream water protects the 

uses specified in section 101(a)(2), then there is no practical difference to whether the new designation 

is “for the first time” or a “revision” as the UAA will need to demonstrate that the use specified in CWA 

section 101(a)(2) is not attainable.

EPA acknowledges the comment that EPA should provide guidance that hydrology is not the only factor 

determining attainability. EPA refers the commenter to section 131.10(g), which provides six factors that 

states and authorized tribes may choose from when conducting a UAA in accordance with 131.10(j). 

While these factors in 131.10(g) were unchanged by today’s rule, EPA notes that it will consider 

providing additional guidance on the factors subsequent to publication of the final rule.

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D. Highest Attainable Use

EPA disagrees with the comment that the HAU should be based purely on a state’s best professional 

judgement (BPJ), as well as the data and information that a state determines is the best available. For a 

response to this comment, please see response essays 5.f.i and 5.k.

EPA disagrees with the comment that EPA should be narrowing states’ and authorized tribes’ discretion 

when determining how to reflect the HAU in WQS. The commenter does not provide a clear example of 

what discretion EPA should narrow. EPA’s regulations provide a nationally consistent framework for how 

states and authorized tribes are to designate uses. Refining that framework, todays’ final rule revisions 

require adoption of an HAU, establish regulatory definitions for HAU and non-101(a)(2) uses, and clearly 

specify what is required to remove designated uses. These rules reasonably balance the need for 

national consistency with allowing states and authorized tribes to designate uses appropriate for their 

site specific situation. EPA does not have evidence nor does the commenter provide evidence showing 

that EPA’s regulations as proposed and finalized will lead to inconsistent implementation of the federal 

regulations. EPA’s preamble and response essays 5.f.i. and 5.k. discuss areas of states and authorized 

tribal discretion relating to these issues. As an example, the preamble to the final rule discusses that, 

states and authorized tribes can choose different approaches that align with their specific needs, as long 

as the approach chosen results in WQS revisions that are consistent with the CWA and section 131.10. 

Please see response essays 5.f.i and 5.k. discussing states’ and authorized tribes’ discretion as it relates 

to the HAU requirement.

EPA disagrees with the comment that states and authorized tribes must adopt a new use category or 

sub-category of use in order to protect the HAU, if existing use categories would not adequately protect 

a water body’s HAU. EPA’s regulations do not require this result but it is true a state or authorized tribe 

may need to adopt a new use category or subcategory in order to protect the HAU. EPA’s rule and 

preamble are clear that states and authorized tribes must adopt the HAU and that “Where a state or 

authorized tribe does not already have a statewide use in their regulation that is protective of the HAU, 

the state or authorized tribe will need to find an approach that meets the requirements of the CWA and 

§ 131.10(g).” Please see response essays 5.f.i. and 5.k. for a fuller discussion of where states and 

authorized tribes have discretion and where they do not in regards to designating uses and the HAU. 

EPA acknowledges the commenter who stated that EPA should explicitly recognize that the HAU may 

not be fishable or swimmable. It is unclear what the commenter meant by this statement. If the 

commenter is stating that the HAU may not be the full use specified in section 101(a)(2) of the Act, but 

rather a sub-category of such a use requiring less stringent criteria (e.g., a limited warm water fishery 

rather than a warm water fishery, or a secondary contact recreation use rather than a primary contact 

recreation use), then the EPA agrees, provided that the adoption of the HAU meets the requirements of 

the CWA and EPA’s regulation. If the commenter is asking EPA to recognize that it may be possible for a 

state or authorized tribe to demonstrate that there is no modified use that is both closest to the uses 

specified in section 101(a)(2) of the Act and attainable, based on the factors in section 131.10(g) that 

preclude attainment of the use (i.e., there is no HAU at all), then -- in that scenario -- EPA agrees that a 

state or authorized tribe may remove the use specified in section 101(a)(2) of the Act and not adopt a 

lesser use (i.e., a HAU) in its place. See the definition of “highest attainable use” at 131.3(m). EPA also 

clarifies that states and authorized tribes are not required to determine whether one broad use category 

is better than another (e.g., to determine that a recreation use is better than an aquatic life use). Rather, 

the intent of the HAU provision is to require states and authorized tribes to adopt a modified use within 

the same broad CWA section 101(a)(2) use category as described in 131.3(m).

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E. Other Comments

EPA acknowledges the suggestion that EPA amend the final rule to include a default use designation 

process. EPA is unclear what the commenter means by a “default use designation process,” but to the 

extent that the commenter is suggesting EPA promulgate the uses specified in section 101(a)(2) of the 

act as default uses to apply to the water bodies for which states or authorized tribes have not yet 

designated any uses (i.e., unclassified waters), EPA disagrees with the comment, at this time, because 

state/authorized tribal-specific designated uses are beyond the scope of this rulemaking. It is very 

important for states and authorized tribes to designate uses for all of their waters of the U.S. because 

states and authorized tribes are tasked with this primary role under the CWA in the first instance and 

such designated uses and the criteria to protect such uses serve the basis for CWA implementing 

programs, many of which states or authorized tribes play a key role. While EPA interprets and 

implements the CWA to create a rebuttable presumption that uses specified in section 101(a)(2) of the 

Act are attainable unless a state or authorized tribe affirmatively demonstrates through a UAA that such 

uses are not attainable, the regulation does not automatically designate the uses specified in CWA 

section 101(a)(2) for all waters. Please see response essay 5.i. for additional discussion on the rebuttable 

presumption. However, the EPA Administrator may determine that new or revised WQS are necessary 

for one or more waters, per CWA section 303(c)(4)(B) and section 131.22, and may propose and 

promulgate new or revised WQS if he/she determines that such WQS are necessary. Please see 

response essays 4.a. through 4.e. for additional discussion on Administrator’s determinations.

EPA acknowledges a commenter’s request for additional discussion on the link between designated and 

existing uses, as well as additional discussion on determining whether a use is an existing use. In 

response, EPA will consider providing additional guidance on this issue after the final rule is published. 

For additional discussion on existing uses, please see response essay 5.d.

For discussion on EPA’s expectations regarding the specificity of use categories, please see response 

essay 5.f.i. For a discussion on defining an existing use, please see response essay 5.d.

EPA acknowledges the comments that it should adhere to the language of section 101(a)(2) of the CWA 

in the context of the final revisions to section 131.10(j). EPA has done so, and the commenters did not 

provide any specific example of how EPA is not adhering to the language of section 101(a)(2).See 

response essay 5.g. for further discussion about 131.10(j).

In response to one commenter, EPA recognizes that some states and authorized tribes have adopted 

state/tribal regulations guiding how they will adopt, revise, or refine designated uses. EPA recommends 

that such states and authorized tribes evaluate their program for consistency with the final regulations. 

States and authorized tribes should work with their EPA regional office as they evaluate their own 

programs to determine what revisions, if any, are necessary.

For discussion on how EPA describes WQS to include antidegradation requirements, please see response 

essay 10.a and 6.g.

Comments regarding water survey techniques and assessments to evaluate aquatic life uses are outside 

the scope of this rulemaking as EPA did not propose regulatory language or request comment on the 

techniques a state or authorized tribe uses to gather data regarding its designated uses.

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To the extent that a comment excerpt is repeating statements from the proposed rule, CWA or preexisting federal regulations, EPA is not responding. Where necessary, EPA corrected any factual 

misstatements. 

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Essay 5.k – Designated Uses: EPA’s Legal Authority

A. Comments regarding EPA’s Authority for the Highest Attainable Use

Requirement

Some commenters questioned the U.S. Environmental Protection Agency’s (EPA’s) authority for the 

highest attainable use (HAU) requirement as being inconsistent with the Clean Water Act (CWA), 

usurping the primary authority and discretion of states and authorized tribes to consider the “use and 

value” of their waters and designated uses under 303(c)(2)(A). EPA acknowledges that states and 

authorized tribes have the primary authority and responsibility to adopt water quality standards (WQS). 

The CWA does not, however, vest sole discretion to the states and authorized tribes to decide on 

appropriate designated uses. The CWA gives EPA an important oversight role and authorizes EPA to 

adopt regulations for implementing the statute. While CWA section 303(c)(2)(A) does require states and 

authorized tribes to establish use designations “taking into consideration” the waters’ use and value for 

a variety of purposes, including public water supplies, propagation of fish and wildlife, recreational 

purposes, and agricultural uses, that same section also directs that “[s]uch standards shall be such as to 

protect the public health or welfare, enhance the quality of water and serve the purposes of [this Act].”

As discussed below, EPA’s regulation requiring the adoption of the HAU when removing a CWA section 

101(a)(2) use is consistent with this directive and reasonably establishes requirements to serve the 

purposes of the Act and enhance the quality of the water. 

EPA’s 1983 regulations established requirements that WQS protect the uses specified in section 

101(a)(2) of the Act unless those uses are shown to be unattainable. The HAU requirement applies after 

the state or authorized tribe has demonstrated that uses specified in section 101(a)(2) of the Act (or 

subcategories of such uses) are not fully attainable but the water body at issue can still support some 

level of protection related to the uses specified in section 101(a)(2) of the Act (i.e., subcategory of a use 

specified in section 101(a)(2) of the Act). As mentioned above, the statutory language in section

303(c)(2)(A) requiring that WQS “shall be such as to enhance the quality of the water and serve the 

purposes of [the Act]” again, provides direction. Generally speaking, the focus of this language is toward 

more protective, not less protective, WQS. Most importantly and relevant to the HAU requirement, the 

CWA 101(a)(2) and 303(c)(2)(A) make clear that states and authorized tribes are to move toward WQS

that protect the uses specified in section 101(a)(2) of the Act wherever those uses are attainable and 

toward the ultimate goal of maintain and restoring the chemical, physical and biological integrity of the 

nation’s waters. EPA disagrees with commenters that the HAU requirements “renders meaningless the 

statutory comment to consider ‘use and value’” and that that “requiring the HAU for every water 

segment would bias the consideration of ‘use and value’ of a water.” It would be inconsistent with the 

CWA given the directive in sections 303(c)(2)(A) and 101(a)(2) goal to allow states and authorized tribes 

to base their designated use decisions solely on consideration of the “use and value” and not protect 

waters for the goal uses where attainable.

Today’s regulation explicitly requires that the HAU be adopted where the state or authorized tribe has 

not demonstrated that the goal’s uses (or subcategories of such uses) are unattainable. This regulation is

reasonable for a number of reasons. First, designated uses are the foundational building block for the 

WQS program. The "use" of a water body is the most fundamental articulation of its role in the aquatic 

and human environment. All of the water quality protections established by the CWA follow from the 

water's designated use. Therefore, an explicit provision requiring states and authorized tribes to adopt 

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the HAU lays the foundation for WQS that continue to “serve” the specific goal of providing for the 

protection and propagation of the uses specified in section 101(a)(2) of the Act and “serve” the statute’s 

overall purpose of restoring and maintaining the integrity of the Nation’s waters as well as the directive 

that WQS enhance the quality of the water. Absent the protection provided by the HAU requirement, a 

state’s or authorized tribe’s (1) failure to adopt any use related to the protection and propagation of 

fish, shellfish, and wildlife, and recreation in or on the water (and thus no criteria) where a waterbody is 

currently attaining or could feasibly attain such a use (even if limited or modified) or (2) adoption of a

designated use less protective than the HAU level (and associated water quality criteria that are less 

protective) could result in the degradation of water quality that would be contrary to the objectives of 

the Act. Such a result would adversely affect aquatic ecosystems and the health of the public recreating 

in or on such waters. Without such protections reflected in the state’s or authorized tribe’s designated 

uses, there will not be a requirement for protective criteria and therefore the CWA implementing 

programs will not be implemented in a manner to achieve those levels of protection. EPA recognizes 

that in some instances the HAU may reflect the status quo (e.g., a subcategory of a use specified in 

101(a)(2) of the Act), but identifying the status quo as the water quality goal will ensure that some water 

quality related to the 101(a)(2) goals are, at a minimum, maintained and would prevent further 

degradation. The HAU requirement employs a step-wise approach to ensure that as states and 

authorized tribes adopt and remove uses that protect for uses specified in 101(a)(2) that they fully 

consider and adopt such uses “wherever attainable.” 

Second, establishing an explicit requirement in the regulations provides a decision-making framework 

that is clear and sets a level playing field for all states and authorized tribes. The rule also provides a 

framework for states and authorized tribes to engage with the public during the public hearing process 

as they adopt new or revised goal uses. In addition, the HAU requirement provides EPA with an 

objective standard by which it can reasonably exercise its oversight authority to ensure that states and 

authorized tribes are considering the relevant information necessary to adopt WQS consistent with 

303(c)(2)(A).

Third, the HAU requirement (as well as the use attainability analysis [UAA] requirement) only apply 

when a state or authorized tribe is revising its designated uses in one of the ways specified in section 

131.10(j). Once such uses are justifiably revised consistent with the relevant requirements, EPA’s 

regulations do not require a UAA or HAU if and when a state or authorized tribe upgrades the 

designated uses for a particular waterbody. See 131.10(k)(2). The regulatory requirements focus on 

revisions that are not protecting for the use specified in section 101(a)(2) of the Act. Specifically, the 

HAU requirement, which serves as a mechanism to ensure that state/authorized tribal WQS maintain

water quality protections for designated uses related to the uses specified in section 101(a)(2), where 

attainable, is a reasonable approach to implementing the CWA consistent with EPA’s oversight 

authority. EPA disagrees with the commenter that argues the lack of a UAA or HAU requirement to 

upgrade a use is “an authorization to the states to be arbitrary and capricious.” In these circumstances 

any new or revised designated uses would still need to meet all the other applicable requirements, 

including 131.10(a) which provides that “[i]f adopting new or revised designated uses other than the 

uses specified in section 101(a)(2) of the Act, or removing designated uses, States must submit 

documentation justifying how their consideration of the use and value of water for those uses listed in 

this paragraph appropriately supports the State’s action.” However, it is important to note that when a 

state or authorized tribe is “upgrading” to adopt the full uses specified in section 101(a)(2), neither a 

UAA nor a use and value demonstration is required. Please see response essay 5.i. for additional 

discussion.

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Finally, the HAU appropriately preserves the primary role of states and authorized tribes in establishing 

designated uses. EPA disagrees with comments that the HAU requirement undermines states’ and 

authorized tribes’ authority to make an appropriate HAU determination. The HAU requirement does not 

restrict the discretion that states and authorized tribes have to weigh evidence relevant to whether uses 

specified in section 101(a)(2) of the Act or subcategories of such uses are not attainable in a particular 

case. In addition, today’s rule specifically provides that there is no required HAU “where the State 

demonstrates that the relevant use specified in section 101(a)(2) of the Act and sub-categories of such a 

use are not attainable.” Title 40 of the Code of Federal Regulations (CFR) section 131.3(m). Similarly, the 

HAU requirement does not remove the discretion that states and authorized tribes have to weigh 

evidence relevant to what is attainable in a particular case. The regulations just require that if a state or 

authorized tribe adopts new or revised WQS based on a required UAA, the state or authorized tribe

must then adopt the “modified aquatic life, wildlife, or recreation use that is both closest to the uses 

specified in section 101(a)(2) of the Act and attainable, based on the evaluation of the factor(s) in 

§ 131.10(g) that preclude(s) attainment of the use and any other information or analyses that were used 

to evaluate attainability.” 

EPA disagrees with commenters that argued that by promulgating the HAU requirement EPA is turning 

the “goals” of the Act into independent requirements. One commenter pointed to the specific language 

in section 101(a) of the CWA that provides that the goals are to be implemented “consistent with the 

provisions of this Act.” The commenter then goes on to note that the language in 303(c)(2)(A) expressly 

gives states the authority to establish uses for waters, “taking into consideration their use and value” for 

a variety of uses. This comment ignores the directive in 303(c)(2)(A) that WQS shall “serve the purposes 

of this Chapter.” EPA is appropriately considering the objective of the Act and the goal as set forth in 

section 101(a)(2) to interpret the statutory language that already exists in CWA section 303(c)(2)(A) in 

developing an appropriate regulatory framework for achieving the objective and 101(a)(2) goal and 

ensuring that “standards shall be such as to protect the public health or welfare, enhance the quality of 

water and serve the purposes of [this Act].”

Today’s rule makes clear that the UAA requirement does not apply to non-101(a)(2) uses. This is a 

significant change from EPA’s previous interpretation laid out in the Advance Notice of Proposed 

Rulemaking (ANPRM) that specified that a UAA is required regardless of the use in question. As 

discussed further in response essay 5.h., EPA is implementing CWA sections 303(c)(2)(A) and 101(a)(2) 

to differentiate between the uses specified in section 101(a)(2) of the Act (and subcategories of such a 

use) and non 101(a)(2) use. As such, today’s rule clearly specifies that the specialized requirements for 

designating or removing uses at section 131.10(g) are not requirement when designating or removing 

non 101(a)(2) uses. Such specialized requirements are specific for uses specified in 101(a)(2) of the Act 

and subcategories of such uses because they are set apart from the CWA 303(c)(2)(A) uses by the goals 

of CWA section 101(a)(2). Rather than being required to conduct a UAA, today’s rule added clarifying 

language in 131.10(a) and (k) explaining that when designating and removing non-101(a)(2) uses “states 

must submit documentation justifying how its consideration of the use and value of water for those uses 

listed in 131.10(a) appropriately supports the state’s or authorized tribe’s action.” This means for non101(a)(2) uses, states and authorized tribes have discretion to weigh the use and value of the designated 

uses so long as their decisions are appropriately supported and meet other applicable CWA

requirements. EPA notes that for non-101(a)(2) uses decisions involving the public health or welfare or 

impact on the quality of the water, that such consideration of the use and value would be consistent 

with requirement in 303(c)(2)(A) that standards “shall be such as to protect public health or welfare or 

enhance the quality of the water.” See essay 5.h. for additional discussion.

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A commenter also questioned EPA’s authority to create a preference for certain designated uses by a 

rulemaking action and argues that today’s rule represents a “fundamental change in the structure of the 

CWA” after contrary administration and implementation. EPA disagrees with this comment. Please see 

response essay 5.h. and 5.j. for a response.

A commenter noted that today’s rule would be the first time EPA would require the HAU. As explained 

in the preamble to the proposed rule (78 FR 54523, September 4, 2013), in order to comply with 40 CFR 

131.6(a) states and authorized tribes will need to adopt designated uses that continue to serve the 

101(a)(2) goal by protecting for the HAU unless the state or authorized tribes has shown that no use 

specified in 101(a)(2) or no subcategory of such uses are attainable. Today’s rule allows for more 

effective implementation by clearly and explicitly articulating the requirement in EPA’s regulation and 

adding a definition. Please refer to the final rule Economic Analysis (EA) for information related to EPA’s 

estimates of burden and costs related to the HAU requirement.

Other commenters contend that because the CWA doesn’t mandate that states and authorized tribes 

develop sub-categories of 101(a)(2) uses, the HAU concept is an intrusion on state flexibility and 

authority. EPA disagrees with these comments. EPA acknowledges that the implementation of the HAU

provision may require the state or authorized tribe to adopt a sub-category. While under EPA’s 1983 

regulation in 131.10(c), subcategories are optional, EPA explained when promulgating that rule that, 

“EPA is attempting to convey the concept that some use classifications included in the Act and in State 

standards are so broad that they do not adequately describe to the public the actual use to be 

protected. The final rule provides that a State may, because of physical, chemical, biological, and 

economic factors, wish to adopt sub-categories of a use and set criteria appropriate to protect a 

particular use sub-category.” Water Quality Standards Regulations, 48 Fed. Reg. 51400, 51409-10 

(November 8, 1983). The requirement to adopt uses to reflect what is attainable that relate to physical, 

chemical, biological and economic factors provided in 131.10(g) is at the heart of the HAU requirement

and as discussed above, such a step-wise approach protects what is attainable to ensure that WQS 

enhance the quality of the water and serve the purpose of the Act. For additional discussion on HAU, 

please see response essays 5.f, 5.f.i, and 5.f.ii.

EPA notes that today’s final rule preamble clarifies how EPA’s prior existing regulations interact with this 

new HAU requirement: “Section 131.10(c) provides that states and authorized tribes “may adopt subcategories of a use...” (emphasis added). This provision generally allows states and authorized tribes to 

adopt sub-categories of the uses specified in the CWA. Today’s rule is finalizing revisions to § 131.10(g) 

to specify that when a state or authorized tribe conducts a UAA required by § 131.10(j), and the state or 

authorized tribe revises its WQS to something other than a use specified in section 101(a)(2) of the Act, 

the state or authorized tribe must adopt the highest attainable modified aquatic life, wildlife, and/or 

recreation use (i.e., a sub-category of an aquatic life, wildlife, and/or recreation use). Where a UAA is 

not required by § 131.10(j), the state or authorized tribe retains discretion to choose whether to adopt 

sub-categories of uses per § 131.10(c).”

One commenter argues that the rule works against 305(b) and 101(b). The commenter cites to 305(b) to 

support an argument that “Congress' intent that costs and benefits be considered in working toward the 

goals of the Act.” The comment goes on to say that “[i]t requires states to submit biennial reports that 

include, among other things, estimates of the "economic and social costs" necessary to achieve the 

objectives of the Act and the "economic and social benefits" of such achievements.” Section 305(b) is 

not addressing adoption of WQS at issue in this rulemaking. EPA notes that its prior existing regulations

allowed for use removals where water quality based controls would result in substantial and widespread 

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social and economic impacts. EPA disagrees with comments that today’s rule is contrary to CWA section 

101(b). EPA acknowledges that states and authorized tribes have primary authority and responsibility to 

adopt WQS but CWA section 303(c) prescribes specific requirements for WQS and provides EPA with an 

important oversight role.

For all the reasons discussed above, EPA’s HAU requirement is consistent with the statute and reflects a 

permissible construction of the statute and therefore EPA is finalizing a rule including the HAU 

requirement.

B. Comments Related to EPA’s Position That Consumption of Aquatic Life Uses 

Are Included under the Uses Specified in Section 101(a)(2) of the Act

EPA disagrees with comments that it is expanding the uses considered under section 101(a)(2) of the 

CWA and that consumption of aquatic life is not a use specified in section 101(a)(2). As discussed in the 

preamble to the proposed rule, since 1992 EPA has publicly articulated its interpretation that the goals 

of the CWA are not only to protect for the propagation of fish, shellfish, and wildlife, but the health of 

the public when consuming fish, shellfish, and other aquatic life.1 Based on the CWA section 303(c)(2)(A) 

requirement that WQS protect public health, EPA interprets the CWA to mean that the uses under 

section 101(a)(2) of the Act are intended to protect public health, as well, and thus includes providing 

for the protection of aquatic communities and human health related to consumption of this aquatic life. 

In other words, not only can the aquatic life thrive in a water body, but when caught, they can also be 

safely eaten by humans.2 In the National Toxics Rule, for example, EPA specified that all waters 

designated for even minimal aquatic life protection (and therefore a potential consumption exposure 

route) are protected for human health.3 EPA also described its interpretation in the October 2000 

Human Health Methodology.4 Consistent with this interpretation, most states and authorized tribes 

have adopted human health criteria as part of the protection for aquatic life uses, as the purpose of the 

criteria is to limit the amount of a pollutant in aquatic species prior to consumption by humans. 

However, states and authorized tribes may also choose to adopt human health criteria as part of their 

protection for recreational uses, recognizing that humans will consume fish and shellfish after fishing, 

which many states and authorized tribes consider to be a recreational use. EPA leaves this flexibility to 

states and authorized tribes as long as the waters are protecting humans from adverse effects of 

consuming aquatic life, unless it has shown that consumption of aquatic life is unattainable, consistent 

with EPA’s regulation.

C. Other Comments

Others commenters contend that the HAU requirement will make the UAA process more burdensome 

and complicated and less likely to result in a state or authorized tribe ever obtaining a credible and 

defensible change to its uses. EPA acknowledges that the adoption of the HAU may require additional 

work on the state’s or authorized tribe’s part but, as discussed, the regulatory requirements are 

reasonable because they limit the HAU to what was used to evaluate attainability to demonstrate that 

the use is not attainable and provide states and authorized tribes with discretion regarding how to 

 

1 78 Fed. Reg. 54522.

2 http://water.epa.gov/scitech/swguidance/standards/upload/2000_10_31_standards_shellfish.pdf. 3 57 Fed. Reg. 60859 (December 22, 1992).

4 http://water.epa.gov/scitech/swguidance/standards/criteria/health/methodology/index.cfm; see pages 4-2 

and 4-3.

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reflect the HAU in their WQS so long as it is consistent with CWA requirements and EPA’s regulation. 

Please see response essay 5.f.i. for additional discussion on any burden that determining an HAU might 

have. To address the concern that the proposed definition will make the UAA process less likely to ever 

result in a state or authorized tribe obtaining a credible and defensible change of designated uses, the 

final rule revised the definition of HAU. The final HAU definition makes clear that the HAU is the use that 

results from the process of determining what is attainable and thus informed by the more objective UAA 

analysis. Finally, EPA believes that the HAU requirement will facilitate moving use changes through the 

public participation process because it will allow the public to assist the state or authorized tribe in a 

collaborative manner to determine the HAU rather than focusing on fighting whether the previously 

designated use is in fact unattainable. Please see section II.B of the final rule preamble and response 

essays 5.e. and 5.f., 5.f.i, and 5.f.ii for additional discussion. 

In regards to the comment questioning the legal authority of EPA to regulate nonpoint source (NPS) 

pollution through the evaluation and use of best management practices (BMPs), or otherwise, EPA’s 

requirement at 131.10(d) existed prior to this action to revise EPA’s rule. EPA did not propose any 

revisions to this provision or to 131.10(h)(2). While EPA discussed these provisions in the preamble, EPA

only took comment on interpretations expressed in the discussion. EPA did not reopen these provisions. 

Nor does the comment address any interpretation expressed. Regarding the comment made, EPA points 

out that its WQS regulations do not regulate NPS pollution nor do they require states to regulation NPS 

pollution. This comment goes beyond the scope of this rulemaking.

Some commenters argued that EPA’s proposal reflects EPA’s intent to re-write the entire 131 

regulations and therefore the entire part is subject to comment. EPA strongly disagrees and provides its 

explanations in essays 1.c. and 3.a.

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