July 2015 EPA 820-S-15-002

Summary of WQS Regulatory Revisions Final Rule

Designated Uses

Final Revision: Amends §131.10(g) to provide that 

where a state/tribe removes or revises a use specified 

in CWA section 101(a)(2) or a subcategory of such a 

use that is not attainable, the highest attainable use 

(HAU) shall be adopted in its place.

HAU is defined 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 subcategories of such a use are not attainable.”

The final rule also amends §131.10(g), §131.10(j), and 

§131.10(k) to clarify when a use attainability analysis 

(UAA) is and is not needed. The final rule defines the 

term “non-101(a)(2) use” and amends §131.10(a) to 

clarify that for such uses while a UAA is not required, 

the state/tribe mustsubmit documentation justifying 

how its consideration of the use and value of water for 

those uses listed in §131.10(a) appropriately supports 

the state/tribal action. 

Goal: Provide clear requirements and ensures

appropriate WQS are in place to help restore and 

maintain robust aquatic ecosystems and promote 

resilience to emerging water quality stressors.

Administrator’s Determination 

Final Revision: Amends §131.22(b) to add a 

requirement that an Administrator’s 

Determination must be signed by the 

Administrator (or duly authorized delegate) 

and include a statement that the document 

is an Administrator’s determination for 

purposes of section 303(c)(4)(B) of the Act.

Goal: Allow EPA and states/tribes to 

communicate directly and specifically on 

areas where WQS improvements should be 

considered and establish a more transparent 

process for the Administrator to announce

determinations made under section 

303(c)(4)(B) of the Act.

Triennial Reviews

Final Revision: Amends §131.20(a) to clarify the 

“applicable water quality standards” that must 

be reviewed triennially. The final rule also 

requires that if a state or tribe chooses not to 

adopt new or revised criteria for any parameters 

for which EPA has published new or updated 

criteria recommendations under CWA section 

304(a), they must explain their decision when 

reporting the results of their triennial review to 

EPA under CWA section 303(c)(1) and 40 CFR 

131.20(c).

Goal: Ensure public transparency and clarify 

existing requirements, so that states and tribes 

update WQS when necessary and consider the 

latest science as reflected in the CWA section 

304(a) criteria recommendations.

EPA finalized updates to the federal water 

quality standards (WQS) regulation at 40 

CFR Part 131 that interprets part of the 

Clean Water Act (CWA). The updates result 

in a better-defined pathway for states, 

territories, and authorized tribes to 

improve water quality and protect high 

quality waters through enhancements in 

the regulation’s effectiveness, WQS 

transparency, and opportunities for 

meaningful public engagement at the state, 

territorial, tribal and local levels.

EPA initially proposed revisions to the WQS 

regulation on September 4, 2013. 

The basic structure of the water quality 

standards regulation (40 CFR part 131) was 

last revised in November 1983. EPA added 

tribal provisions in 1991, “Alaska rule” 

provisions in 2000, and BEACH Act rule 

provisions in 2004.

The requirements have provided a strong 

foundation for water quality-based controls, 

including water quality assessments, impaired 

waters lists and total maximum daily loads, 

under CWA section 303(d), as well as for 

water quality-based effluent limits in 

discharge permits under CWA section 402. 
July 2015 EPA 820-S-15-002

Summary of WQS Regulatory Revisions Final Rule

The final rule also includes other changes to 

correct mistakes and inconsistencies in Part 

131.

For more information and to access 

supplemental documents and the docket for 

this rulemaking, see EPA’s WQS website at: 

http://water.epa.gov/lawsregs/lawsguidance

/wqs_index.cfm.

WQS Variances

Final Revision: Adds §131.14 to provide a 

comprehensive regulatory structure for and 

explicitly authorize the use of WQS variances. The 

final rule clarifies:

 (1) that a WQS variance is a water quality

 standard subject to EPA review and approval or 

 disapproval.

 (2) how WQS variances relate to other CWA 

 programs and specifies the information that the 

 state/tribe must adopt in any WQS variance, 

 and/or the water body or waterbody segments 

 to which the WQS variance applies, and a

 quantifiable expression of the highest attainable 

 condition.

 (3) that states/tribes must submit to EPA

 supporting documentation that demonstrates 

 why the WQS variance is needed and justifies the 

 term and interim requirements. 

 (4) that states/tribes must reevaluate WQS 

 variances longer than five years on an 

 established schedule with public involvement.

Goal: Promote the appropriate use of WQS 

variances when applicable WQS are not attainable in 

the near-term but may be attainable in the future, 

and provide regulatory certainty to states, tribes, the 

regulated community, stakeholders, and the public in 

making progress toward attaining designated uses

and criteria that protect such uses.

Antidegradation

Final Revision: Amends provisions of §131.12 to 

specify that states/tribes:

 (1) may identify high quality waters on either 

 a parameter-by-parameter approach, or 

 on a waterbody-by-waterbody approach that 

 does not exclude water bodies from Tier 2 

 protection solely because water quality does 

 not exceed levels necessary to support all of 

 the CWA section 101(a)(2) uses. When using 

 the water body approach, states/tribes must 

 involve the public in any decisions pertaining 

 to when to provide Tier 2 protection, and the 

 factors considered in such decisions.

 (2) must evaluate a range of practicable 

 alternatives that would prevent or lessen the 

 degradation associated with the proposed 

 activity. When the analysis of alternatives 

 identifies one or more practicable 

 alternatives, the state/tribe must only find 

 that the lowering is necessary if one of those 

 alternatives is selected for implementation. 

 (3) must provide an opportunity for public 

 involvement during the development and any 

 subsequent revisions of antidegradation 

 implementation methods (whether or not 

 those methods are adopted into rule), and to 

 make the methods available to the public.

Goal: Promote public transparency and enhance 

antidegradation implementation through clearer 

requirements and expectations.

Provisions Authorizing the Use of 

Permit-Based Compliance Schedules 

Final Revision: Adds §131.15 to clarify that a 

permitting authority may only issue compliance 

schedules for water quality-based effluent 

limitations in National Pollutant Discharge 

Elimination System permits if the state or tribe

has authorized the use of such compliance 

schedules in their WQS or implementing 

regulations. The final rule requires that such 

authorizing provisions must be approved by 

EPA as WQS under CWA section 303(c).

Goal: Clearly articulate in regulation what must 

be done for states and tribes to be able to 

utilize permit compliance schedules, consistent 

with the CWA and the EPA Administrator’s 

decision in In the Matter of Star-Kist Caribe, 

Inc., and ensure public transparency on 

state/tribal decisions to allow permit 

compliance schedules.