State-Specific Water Quality Standards Effective under the Clean Water Act (CWA)

Modernizing Public Hearings for WQS Reviews

The document suggests how states and authorized tribes can conduct online public hearings in lieu of in-person public hearings, consistent with federal public hearing requirements.

EPA has compiled state, territorial, and authorized tribal water quality standards that EPA has approved or are otherwise in effect for Clean Water Act purposes.  This compilation is continuously updated as EPA approves new or revised WQS.

Please note the water quality standards may contain additional provisions outside the scope of the Clean Water Act, its implementing federal regulations, or EPA's authority. In some cases, these additional provisions have been included as supplementary information.

EPA is posting the water quality standards as a convenience to users and has made a reasonable effort to assure their accuracy. Additionally, EPA has made a reasonable effort to identify parts of the standards that are approved, disapproved, or are otherwise not in effect for Clean Water Act purposes.

Please contact the appropriate Regional EPA Water Quality Standards coordinator for questions about water quality standards for a particular state, tribe, or territory.

On this page:

Select Water Quality Standards Information for a Specific State, Territory, or Tribe

Each state, territory, and authorized tribe has a page on this website containing information about their relevant WQS, including those in effect for CWA purposes.  Other information may also be included (for example, contact information, federal promulgations, etc.).  Select the state on the map or using the Select state, territory, or authorized tribe selector.

MapAlabama Alaska Arizona Arkansas California Colorado Connecticut Delaware Washington, DC Florida Georgia Hawaii Idaho Illinois Indiana Iowa Kansas Kentucky Louisiana Maine Maryland Massachusetts Michigan Minnesota Mississippi Missouri Montana Nebraska Nevada New Hampshire New Jersey New Mexico New York North Carolina North Dakota Northern Mariana Islands Guam Ohio Oklahoma Oregon Pennsylvania Puerto Rico Rhode Island South Carolina South Dakota Tennessee Texas Utah Vermont Virginia Washington West Virginia Wisconsin Wyoming US Virgin Islands American Samoa


Search State, Territory, or Authorized Tribe Criteria

Criteria: A Key Component of Water Quality Standards

Criteria are one of the three components of a water quality standard (WQS): criteria, designated uses, and antidegradation requirements.

  • Water quality criteria are the limits on magnitude, duration, and frequency for specific parameters that support the waterbody's designated uses.  Parameters can be chemical (e.g., concentrations of particular substances, conductivity, etc.) or physical (e.g., temperature, flow conditions, clarity, etc.).
  • Designated uses are the expressed goals for using the waterbody, including support of aquatic life, human health (e.g., fish consumption, public water supply etc.), and recreational uses (e.g., swimming, boating, etc.).
  • Antidegradation requirements provide a framework for maintaining and protecting water quality that has already been achieved.

Together, these components enable the following:

  • Comparisons of monitoring data to determine whether a waterbody’s designated uses have been attained (or are impaired).
  • Formulation of quality-based, effluent limitations in discharge permits for maintaining (or restoring) attainment of a waterbody’s designated uses.
  • Calculation of total maximum daily loads of pollutants for restoring and maintaining a waterbody’s designated uses.

For more detailed information about WQS and how they are used, visit the links.

EPA has extracted numeric criteria data for pollutants and other parameters from state, tribal, and territorial WQS regulations in effect for CWA purposes and organized them into this criteria search tool. This tool also includes the following criteria that EPA has recommended or promulgated:

Important!

  • The numeric criteria data summarized in this tool are not a substitute for those in the source WQS regulations that EPA has approved or are otherwise in effect for CWA purposes.
  • The tool points to the source regulations that provide contextual details such as duration, frequency, and other nuances as to how the criteria are applied.
  • Narrative criteria - which are not included in this search tool - are included in the source WQS regulations that were used for the numeric criteria.

How to Use this Tool

Using this tool, you can identify water quality criteria from the following two search perspectives:

Both perspectives organize criteria using the magnitude values of parameters as related to each state's application of the parameter.  The source linking the criterion to EPA-approved state regulation is also included.

Application

Criteria applications are generally direct or indirect expressions of the related designated uses which depend on the particular state's regulations.  Direct applications explicitly specify the designated uses to which the criterion applies (e.g., water supply).  Indirect applications indicate one or more waterbodies or classes of waterbodies to which the criterion applies; the actual designated uses for these waters are identified elsewhere in the state’s regulations or other supporting documents.

Note: Names for a specific designated use can vary between states.  For example, drinking water supply, municipal supply, and potable water supply are names for the same designated use.

Parameter

A parameter is a specific characteristic of the water body; it can be chemical (e.g., concentrations of particular substances, conductivity, etc.) or physical (e.g., temperature, flow conditions, clarity, etc.).

Note: Parameter names can vary from state to state.  For example, silvex is the same parameter as 2,4,5-trichlorophenoxy proprionic acid.  EPA has made a reasonable effort to link pollutants with their synonyms so  you'll be presented with a more complete listing of a pollutant's criteria across states.

For chemical parameters, a link is provided to the chemical on EPA's CompTox Chemicals Dashboard. The dashboard is a comprehensive source for chemistry, toxicity, and exposure information for over 875,000 chemicals.

Magnitude

Currently, only criteria magnitudes for parameters are summarized in the tool.  Durations, frequencies, and other factors may be included in the state's regulation.

Note: Magnitudes for site-specific criteria may be presented as a range in the tool.  Criteria for the individual sites are included in the state regulation.

Source

To provide context and details for the specific criterion (or criteria), each row has a button that links to the PDF page what's printed on the document itself. of the state regulation in-effect for CWA purposes.  These source documents are also located on the state's WQS Information page.

Search Criteria by State, Territory, or Authorized Tribe

Select the state, territory, or authorized tribe to generate the criteria table.  Each criterion has a button that links to the source regulation to provide appropriate context.

Note: Selecting the button should open the regulation to the PDF page what's printed on the document itself.. Otherwise, the source button indicates the appropriate page as indicated by the PDF file viewer.


 
 

Search Criteria by Parameter

To select a parameter, start typing it into the box.   Doing so will generate a list of parameters included in the tool's database.  For parameters that are chemical substances, you can also select pollutants using its CAS Number without any dashes (e.g., 93721 — not 93-72-1).

Once you see your parameter-of-interest, select it to generate the criteria table. In many cases, the table will include parameters listed under different names (synonyms) depending on the state, territory, or authorized tribe.  Each criterion has a button that links to the source regulation to provide appropriate context.

Note: Selecting the button should open the regulation to the PDF page what's printed on the document itself.. Otherwise, the source button indicates the appropriate page as indicated by the PDF file viewer.

 
 

Download Criteria Spreadsheet

Data from the search tool are available for download as a "flat" spreadsheet file to help support custom searches and analyses.

Contact Us to ask a question, provide feedback, or report a problem.
Last updated on July 18, 2024