Water Quality Standards Regulations: Massachusetts

Presented are water quality standards in effect for Clean Water Act (CWA) purposes for this state.

The EPA is posting these standards as a convenience to users and has made a reasonable effort to assure their accuracy. For each document listed under "State Standards in Effect for CWA Purposes", the EPA has made a reasonable effort to identify parts of the standards that are disapproved or are otherwise not in effect for CWA purposes. Additionally, please note the documents may also contain provisions that the EPA does not have the authority and duty to act on under the Clean Water Act because the provisions are not water quality standards.

• What is a New or Revised Water Quality Standard Under CWA 303(c)(3)? - Frequently Asked Questions (pdf) (108.04 KB)

• State Standards in Effect for CWA Purposes
• Federally Proposed or Promulgated Standards

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State Standards in Effect for CWA Purposes

• Massachusetts Surface Water Quality Standards (2023) (pdf) (12.84 MB)
  (Effective May 1, 2023) Surface water quality standards for the state of Massachusetts. Please note that not all parts of this document are effective for Clean Water Act purposes. Refer to cover pages for more information.
• Antidegradation Review Procedure for Discharge Requiring a Permit Under 413 CMR 3.03 (1993) (pdf) (1.09 MB)
• Massachusetts Surface Water Quality Standards Implementation Policy for Mixing Zones (1993) (pdf) (653.49 KB)
• Massachusetts Water Quality Standards Implementation Policy for the Control of Toxic Pollutants in Surface Waters (1980) (pdf) (1.02 MB)

Variances

• Final Variance for the MWRA CSO Control Plan in the Charles River Basin (10/1/2010) (pdf) (545.08 KB)
• Final Variance for CSO Discharges to the Alewife/Upper Mystic Basin (9/1/2010) (pdf) (715.15 KB)

Combined Sewer Overflows and Wet Weather

• Final Administrative Determinations for CSO-Impacted Waters Within the Massachusetts Water Resources Authority (MWRA) Sewer Service Area (1997) (pdf) (512.65 KB)
  The document identifies the water quality classifications that apply to CSO-impacted waters.
• Policy for Abatement of Pollution From Combined Sewer Overflows (1997) (pdf) (987.29 KB)
• Stormwater Management, Volume One: Stormwater Technical Handbook (1997) (pdf) (5.11 MB)
• Stormwater Management, Volume Two: Stormwater Technical Handbook (1997) (pdf) (14.78 MB)

Thermal Discharges

• Memorandum on Thermal Discharge/NPDES Review (6/9/1992) (pdf) (555.93 KB)

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Federally Proposed or Promulgated Standards

• None at this time.