Integrated Lists of Waters & Related Reports

For the upcoming 2028 Integrated Report (IR), MassDEP is working on comprehensive statewide assessments of designated uses, as established in the Massachusetts Surface Water Quality Standards (314 CMR 4.00).  While not available for the current cycle, assessments of the Aquatic Life Use will be included (along with the assessments of other designated uses) into the 2028 IR.

MassDEP has available for public review and comment the DRAFT 2024/2026 Integrated List of Waters (“Integrated Report” or IR), which represents the most recent update on the status of Massachusetts’ waters. This report is submitted to the United States Environmental Protection Agency (EPA) every two years in fulfillment of the reporting requirements of sections 305(b) (Summary of Water Quality Report) and 303(d) (List of Impaired Waters) of the Clean Water Act (CWA).  The development of the 303(d) List (Category 5 of the IR) includes a public review and comment process. Written comments on the draft 2024/2026 IR (provided below) should be submitted no later than 5:00 PM on February 10, 2026 via email to dep.wpp@mass.gov. MassDEP plans to address all public comments in a Responses to Comments document that will be posted with the final IR. A resulting final version of the 303(d) list will be submitted to EPA for approval.

For MassDEP’s 2024/2026 draft IR, quality-controlled data submitted by external groups to DEP prior to the pre-established deadline of 1/18/2023 were reviewed for quality and resulting usable data were considered in IR decision-making for designated uses assessed. External data submitted after the deadline will be reviewed and considered for possible use in a future IR cycle.

MassDEP’s draft 2024/2026 IR consists of the following specific documents and files, submitted to EPA and the public under the requirements of the CWA: 

• Integrated Report (IR), including tables for each category
• IR Appendices 1-5 document, presenting the proposed changes from the 2022 IR, the list of EPA-approved “Actions”, Assessment Units and integrated list categories, impairments added to the 2024/2026 integrated list, impairments removed from the 2024/2026 integrated list, and impairments changed from the prior (2022) reporting cycle.
• IR Appendices 6-38 are watershed-based Assessment and Listing Decision Summary documents for each of the watershed and/or coastal drainage areas updated. Each document contains the supporting data and rationale for each use attainment status update including delisting decisions. Associated maps for each updated watershed and/or coastal drainage area depicting AUs, monitoring stations, dams, discharges, and public beaches are also included to provide spatial orientation as complementary appendices.
• A worksheet summarizing proposed changes from the final 2022 IR to the 2024/2026 IR

MassDEP submitted the proposed final 2022 IR to EPA in May 2023.  In addition to the main narrative report and related appendices (1-5), documentation of the assessment and listing decisions made for the 2022 IR was provided in individual decision summary documents for each watershed and/or coastal drainage area assessed (Appendices 6-26). Each appendix summarized the most recent assessments for each existing assessment unit in the watershed and included a table with all impairments added, removed, or changed between the 2018/2020 and 2022 reporting cycles. Data and information supporting all decisions to remove impairments were included in the decision summaries. Also, Appendix 27 provided a summary of changes from the draft to final IR.

For the 2022 IR, quality-controlled data submitted to MassDEP prior to the pre-established deadline of January 15, 2021, were considered relative to the watersheds that were assessed. Data submitted after the deadline were not considered for the 2022 IR but are being reviewed and considered for use in a subsequent cycle, dependent on the planning for future IR cycles.

On June 30, 2023, MassDEP received a partial approval letter from EPA for the 2022 IR. The letter specified 303(d) list decisions that EPA approved, in addition to decisions related to secondary contact recreation that EPA deferred approving (i.e., “deferred action” on). EPA approved the vast majority of the 303(d) list but deferred action on Secondary Contact Recreation use attainment decisions that met the following two conditions: 1) the waters were not included as impaired or threatened on the 303(d) list submitted by MassDEP, and 2) data and information pertaining to bacteria impairment status for the waters were available. EPA deferred action on these waters until EPA and MassDEP developed a consensus approach for assessing bacteria data and information for the Secondary Contact Recreation use. MassDEP coordinated with EPA on the methodology for utilizing bacteria data for Secondary Contact Use assessment to be implemented in the subsequent IR.

For a geospatial view of current and historic water quality assessment and listing decisions, open WPP’s Water Quality Data Viewer (under the Integrated List of Waters view).  This information can also be viewed using the MassMapper application (select “Regulated Areas” to access the individual data layers for the DEP Integrated List of Waters: rivers, lakes/estuaries, and watersheds) and can be downloaded at MassGIS (URL pending).