Use Attainability Analysis and the Use Revision Process

This interactive diagram is intended to help states, authorized tribes, and territories establish or revise designated uses by addressing the steps and questions they should consider while conducting a Use Attainability Analysis (UAA). In general, a UAA is required when revising designated uses related to protecting aquatic life, wildlife, and recreation in and on the water specified in Clean Water Act (CWA) section 101(a)(2).  However, this diagram may also be helpful when establishing or revising other uses (i.e., "non-101(a)(2) uses"). 40 CFR 131.10 details when a UAA is required and the specific requirements for establishing and revising designated uses.

Please note that while the questions presented in this process diagram are intended to be comprehensive, this 4-step diagram is a starting point for conducting a UAA. Users may need to ask themselves additional questions to more accurately capture case-specific information for a particular UAA.

Select the steps to view details, including tips for use revisions related to combined sewer overflows (CSOs).

Interactive Diagram: Overview of UAA and Use Revision Process

Step 1 Identify the Waterbody Characteristics

Step 2 Analyze the Data

Step 3 Draft the UAA and Regulatory Language

Step 4 Conduct the Rulemaking Process

Potential Resources and Tools

• Waterbody-Specific Resources and Tools
  • Current economic data for communities near the waterbody.
  • UAA protocols for the state, authorized tribe, or territory.
  • Alternatives analyses evaluating activities that could remedy any of the anthropogenic stressors.
  • Approved Long Term Control Plans (LTCP) for any CSOs that discharge into the waterbody.
  • National Pollution Discharge Elimination System (NPDES) permits from any facilities discharging into the waterbody.
  • Total Maximum Daily Loads (TMDL) for the waterbody.
• General Resources and Tools
  • State-Specific Water Quality Standards Effective under the Clean Water Act

  • Final Rulemaking to Update the National Water Quality Standards Regulation

  • Examples of UAAs (Case Studies)
  • Questions and Answers on EPA's Existing Use Policy, Letter to Mr. Derek Smithee, State of Oklahoma Water Resources Board (pdf)(12 pp, 3 MB)
  • Protection of Downstream Waters in Water Quality Standards: Frequently Asked Questions (pdf) (12 pp, 567 K)
  • Spreadsheet Tools to Evaluate Economic Impacts - Private Sector | Public Sector
  • Options for Modernizing Public Hearings for Water Quality Standard Decisions Consistent with 40 CFR 25.5
  • National Water Quality Monitoring Council: EPA USGS Water Quality Portal

Interactive Diagram: Overview of UAA and Use Revision Process

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Step 1 Identify the Waterbody Characteristics

1. Identify the affected waterbody and its characteristics.
2. Describe the stressors limiting attainability of the designated use.
3. Identify the existing uses.

A

• What waterbody is affected?
• What are the applicable designated uses?
• What is the designated use with attainability concerns?CSO Tip
• What are the applicable criteria for the designated use in question?CSO Tip
• Are any of the applicable narrative or numeric criteria for the designated use in question being exceeded?
• What is the geographic scale of the water quality problem?CSO Tip
• Are there spatial or temporal variations within the waterbody?CSO Tip 1CSO Tip 2CSO Tip 3

B

• Explore and identify the stressors limiting attainability of the designated use and document the data resources used.CSO Tip 1CSO Tip 2
  • Are the stressors specific pollutants? If so, what are they and their sources?CSO Tip 1CSO Tip 2
  • Are the stressors habitat-related?
  • Are the stressors natural or anthropogenic?
  • If multiple stressors are identified, which have the greatest influence on attainability of the designated use?CSO Tip
  • What stressors are controllable and why (or why not)? Documenting this is useful to help prioritize resources.

C

• Gather current and historical water quality monitoring data and information on the waterbody's uses.  This includes information such as records, photographs, interviews with town residents or residents adjacent to the waterbody on the public’s use of the waterbody.
  • When did the use-limiting stressors begin?CSO Tip
  • When did they begin to affect the waterbody?
• What are the uses that have actually occurred and what level of water quality has been attained to support those useson or after November 28, 1975?CSO Tip
• Where data may be limited, inconclusive, or insufficient regarding whether the use has occurred or the water quality has been attained, states and authorized tribes have flexibility to evaluate the strength of the available data and information to decide if the uses are indeed existing.

Interactive Diagram: Overview of UAA and Use Revision Process

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Step 2 Analyze the Data

1. Identify feasible activities and/or controls to address the stressors and determine if the designated use and criteria are attainable.
2. Identify the highest attainable use (HAU).

A

• What activities and/or controls to address the stressors have already been tested, implemented and/or require further study?CSO Tip
• Is the applicable designated use and criteria attainable after implementing various activities and/or controls already underway?CSO Tip
• If not, are there any additional activities and/or controls, such as those found in an integrated plan, watershed plan, or TMDL, to address the stressors that could mitigate the waterbody impacts and to what degree?
• Which of these activities and/or controls would result in attaining the applicable designated use and criteria?CSO Tip
  • Are there known methods (activities and/or controls) to remedy any of the identified stressors?
  • Have any such activities and/or controls already been implemented in other situations? If so, for how long and to what level of success?
  • Has the state or authorized tribe done an alternatives analysis to evaluate and compare the activities and/or controls that could remedy any of the identified stressors? If not, consider conducting such an analysis. Although not required, it would facilitate determining which activities and/or controls could attain the designated use and whether such activities and/or controls are feasible.CSO Tip
• Are any of these activities and/or controls feasible for this situation/analysis? Is any additional information needed to make this determination? If so, identify how to obtain that information and whether that information can be obtained for this analysis.
• If there are no feasible activities and/or controls that could be implemented to attain the applicable designated use and criteria, identify which factor at 40 CFR 131.10(g) precludes attainment of the designated use and criteria.CSO Tip 1CSO Tip 2

B

• Based on previous steps, determine which activities and/or controls could address the stressors to the waterbody and reverse the impacts to some degree thereby improving water quality conditions, even if not attaining the currently applicable designated use and criteria. Consider how changes in precipitation impact the effectiveness of these activities.CSO Tip
• When determining the HAU, consider changes in precipitation as a result of climate change that could lead to unattainability of the designated use.
• Determine the use and the associated criteria that could be attainable with implementation of these feasible activities and/or controls despite the impact of the identified factor or stressor. Use the analysis done to document why this is the HAU.CSO Tip

Interactive Diagram: Overview of UAA and Use Revision Process

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Step 3 Draft the UAA and Regulatory Language

1. Document the findings from Steps 1 and 2.
2. Draft regulatory language for the use revision based on that UAA information.

A

• Explain how the state, authorized tribe, or territory evaluated the attainability of the designated use.
• Document the stressors which limit the attainability of the designated use.
• Document the existing uses and the data used to determine the existing uses.
• Name the feasible activities and/or controls that would address the stressors impacting the attainability of the designated use and the extent to which they would address the stressors.
• Explain why the feasible activities and/or controls would not lead to attainment of the designated use.
• Identify and demonstrate which 131.10(g) factor precludes attainment of the designated use.
• Explain how the state, authorized tribe, or territory determined the HAU.

B

• Replace the unattainable designated use with the HAU.CSO Tip

Interactive Diagram: Overview of UAA and Use Revision Process

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Step 4 Conduct the Rulemaking Process

1. Engage with EPA to ensure all needed components are included in the UAA package prior to public outreach.
2. Engage EPA for pre-proposal review and discussion (in addition to being engaged throughout the process, this crucial step allows for yet another opportunity for issues to be raised to be resolved in a timely fashion).
3. Propose use revisions with the supporting UAA and ensure that all public participation requirements have been met (e.g., public notice, public hearing).
4. Address public comments and make any corresponding revisions.
5. Adopt final use revisions into the WQS regulations and submit them along with the UAA to EPA.
6. After receiving the complete WQS revisions package including the UAA, EPA will review the revisions for approval or disapproval. The statutory timeframe for review and EPA action is 60 to 90 days. The use revision becomes effective for CWA purposes upon EPA approval.