Data source

Section 303(d) of the Federal Clean Water Act requires states to identify waterbodies that fail to meet water quality standards even after technology-based pollution controls are applied. Massachusetts submits a biennial Integrated List of Waters to EPA on April 1 of even-numbered years, combining a full 305(b) water quality assessment with the required 303(d) impaired waters listing. EPA typically reviews and approves submissions within 6–18 months.

The Integrated List is the primary tool for tracking water quality outcomes in Massachusetts. It forms the basis for TMDL (Total Maximum Daily Load) development — legally required cleanup plans that set the maximum amount of a pollutant a waterbody can receive while still meeting standards. Every waterbody listed as impaired in Category 5 must have a TMDL developed for it.

EPA maintains the national ATTAINS (Assessment, Total Maximum Daily Load Tracking and Implementation System) database, which stores all state 303(d) submissions. MA’s approved list cycles and EPA correspondence are documented on the EPA Region 1 Impaired Waters page. Individual waterbody conditions can be explored via EPA’s How’s My Waterway tool.

Assessment categories:

Category	Meaning
1	Fully Supporting all designated uses
2	Attaining standards (some minor concern)
3	Insufficient information to assess
4A	Impaired — TMDL completed and approved
4B	Impaired — addressed through other required plans
4C	Impaired — addressed through alternative control requirement
5	Impaired — TMDL needed (the “303(d) list” proper)

Data available in AMEND: Reporting cycles 2010, 2012, 2014, 2016, 2018, and 2022. The 2020 cycle was not published by MassGIS. The 2024/2026 cycle is in draft as of April 2026 and will be added when EPA approves the MA submission.

This data is sourced from MassGIS (Massachusetts Bureau of Geographic Information), which publishes each approved cycle as shapefiles with tabular attribute files.

The data from MassGIS has been archived on this site, last updated on 12 April 2026 10:23 am (latest cycle: 2022). AMEND checks weekly and will automatically incorporate new data when MassGIS publishes a new cycle; because data is only released biennially, no new data will appear between cycles.

Download archive

• 303(d) impairments (all cycles) — one row per assessment unit × designated use × impairment cause × cycle

Data visualization

Trend in impaired waters over time

Causes of impairment (2022)

Data table

A random sample of 10 rows from the full dataset is shown below for illustration.

Cycle	Waterbody	Watershed	Water Type	Use	Attainment	Cause	Category
2010	Buttonwood Park Pond	Buzzards Bay	FRESHWATER LAKE	Aquatic Life	Not Assessed		3
2010	Little Rocky Pond	Buzzards Bay	FRESHWATER LAKE	Aesthetic	Not Assessed		3
2012	Notown Reservoir	Nashua	FRESHWATER LAKE	Public Water Supply	Not Assessed		3
2012	Tighe Carmody Reservoir	Connecticut	FRESHWATER LAKE	Public Water Supply	Not Assessed		3
2014	Parker Pond	Millers	FRESHWATER LAKE	Primary Contact Recreation	Not Supporting	Aquatic Plants (Macrophytes)	4A
2014	Round Pond (East)	Cape Cod	FRESHWATER LAKE	Secondary Contact Recreation	Not Assessed		4A
2016	Pratts Pond	Blackstone	FRESHWATER LAKE	Secondary Contact Recreation	Not Assessed		3
2016	Sawmill Brook	Charles	RIVER	Primary Contact Recreation	Not Supporting	Organic Enrichment (Sewage) Biological Indicators	5
2018	Shaw Brook	Westfield	RIVER	Fish Consumption	Not Assessed		2
2018	Egypt River	Parker	ESTUARY	Fish Consumption	Not Assessed		5