2021 Triennial Review of Maine’s Water Quality Classifications and Related Standards

Triennial Review of Maine's Water Quality Standards


Maine's water quality standards describe what uses, such as recreation or fishing, are appropriate for which waterbodies, and which criteria and antidegradation measures are in place to protect those uses. More information on Maine's water quality standards can be accessed on DEP's Water Quality Standards page, which provides links to existing Maine statutes and rules.

The federal Clean Water Act (§303(c)(1); 40 CFR Part 131.20 - federal rules, off-site) requires that states periodically, but at least once every 3 years, hold public hearings for the purpose of reviewing water quality standards and, as appropriate, modifying and developing standards. This process in known as the Triennial Review. Maine Statute contains similar language in 38 M.R.S.§464.3.B.

The Department is now in the process of conducting a Triennial Review, which is expected to extend into 2022 for any required legislation. To start the process, on January 6, 2020 a request to submit proposals on changes to Maine's water quality standards was sent to recipients at Non-Governmental Organizations, municipalities, tribes, state and federal agencies, etc. Submission guidelines including a timetable were included in the mailings. In addition, the Department also issued a press release to announce the start of the process.

Following internal review, the Department developed recommendations for changes to existing water quality standards and received public comment in the spring of 2021. During the summer and fall of 2021, the Board of Environmental Protection conducted a public hearing and received public comment on the Department’s revised recommendations. In December 2021, the Board voted on final revised recommendations , and on January 4, 2022, the Board submitted the final revised recommendations and revised responses to comments on changes to existing standards to the Maine Legislature as the institution responsible for making statutory changes. Ultimately, the U.S. Environmental Protection Agency must give final approval to any changes made by the State of Maine.

Proposals for Updates to Maine Water Quality Standards

The Department received proposals to change water quality standards, including water quality classifications, from the U.S. Environmental Protection Agency (USEPA) and stakeholders, and also developed its own proposals.

Proposals for updates to water quality standards (WQS). The USEPA and three stakeholders submitted proposals:

    • Expand existing recreational WQS for Class GPA by including standards for cyanotoxins.
    • Update regulations for surface water quality criteria for toxic pollutants relating to the protection of aquatic life (aluminum, ammonia, copper and selenium, ambient water physical characteristics).
    • Update lower end of freshwater range for pH from 6.0 to 6.5.
    • Expand regulations relating to water temperature in tidal waters.
    • Eliminate applicability of natural conditions clause to water quality criteria intended to protect human health (toxics, bacteria).
    • Clarify that statute on waiver or modification of protection and improvement laws does not apply to WQS.
    • Expand mixing zone policy.
    • Update recreational water quality criteria for Classes B, C, SB and SC to be applicable year-round.
    • Add National Shellfish Sanitation Program shellfishing criteria to Class SA.
  • Citizen Proposal
    • Develop acid rain-based WQS.
    • Supporting documents are available on request.
  • Friends of Graham Lake
    • Develop turbidity WQS.
    • Supporting documents are available on request.
    • Expand bacteria reporting units in all classifications to include 'MPN'.

The Department developed 3 proposals:

  • Clarify aquatic life standards for Class B, C, GPA, SB and SC waters.
  • Expand definition of Outstanding National Resource Waters to include waters in National Monuments.
  • Update upper end of freshwater range for pH from 8.5 to 9.0.

Proposals for upgrades of water quality classifications. The USEPA and three stakeholders submitted proposals (numbers refer to items in Figure 1):

    • (11) Upgrade to Class B: Long Creek (Westbrook).
  • Grow L/A and Friends of Merrymeeting Bay
    • (1) Upgrade to Class B: Androscoggin River from Gulf Island Pond to the mouth of the Androscoggin in Merrymeeting Bay at a line between Pleasant Pt. (Lewiston, Auburn, Lisbon, Durham, Topsham, Brunswick).
    • Supporting documents are available on request.
    • LD 676, An Act to Reclassify Part of the Androscoggin River to Class B, was submitted to the 130th Legislature.
  • The Nature Conservancy
    • (4) Upgrade to Class A: Donnell Pond – tributaries (T9 SD BPP, T10 SD BPP, Franklin, Sullivan)
    • (5) Upgrade to Class AA: East and West Branches Penobscot River - tributaries in Katahdin Woods and Waters National Monument (WELS: T5 R7, T5 R8, T4 R7, T4 R8, T3 R7, T3 R8, T2 R8; Soldiertown TWP/T2 R7 WELS).
    • (19) Upgrade to Class AA: Southwest Branch St. John River (T9 R17 WELS, T10 R16 WELS, Big Ten Township).
    • (20) Upgrade to Class AA: Upper West Branch Penobscot River and tributaries (WELS: T5 R11, T4 R10, T4 R11, T3 R10, T3 R11, T2 R9, T2 R10, T2 R12, T1 R9, T1 R10, T1 R11, T1 R12, TA R11; Nesourdnahunk TWP, Mt. Katahdin TWP, Rainbow TWP, Shawtown TWP).
  • Friends of the Presumpscot River
    • (16) Upgrade to Class B: Presumpscot River from Saccarappa Falls to Head of Tide at Presumpscot Falls (Westbrook, Portland, Falmouth).
    • Supporting documents are available on request.

The Department developed 13 proposals (numbers refer to items in Figure 1 below):

  • (2) Upgrade to Class B: Cambolasse Stream (Lincoln)
  • (3) Upgrade to Class AA: Chain Lakes Stream (Wesley)
  • (6) Upgrade to Class A: East and West Branches Nezinscot River – tributaries (Buckfield, Hartford, Paris, Peru, Sumner, West Paris, and Woodstock)
  • (7) Upgrade to Class AA: Fletcher Brook and tributaries (T36 MD BPP, T37 MD BPP, T42 MD BP)
  • (8) Upgrade to Class AA: Houston Brook and tributaries (Elliotsville TWP, T7 R9 NWP, Katahdin Iron Works TWP)
  • (9) Upgrade to Class A: Little Androscoggin River (upper) – tributaries (Greenwood, Woodstock, Albany TWP)
  • (10) Upgrade to Class AA: Little Narraguagus River (T28 MD BPP)
  • (12) Upgrade to Class AA: Magazine Brook (T37 MD BPP, T42 MD BP)
  • (13) Upgrade to Class A: Medunkeunk Stream – tributaries (Medway, TA R7 WELS, Woodville, T2 R9 NWP, Chester, T2 R8 NWP)
  • (14) Upgrade to Class A: Mount Blue Stream and tributaries (Weld, Avon)
  • (15) Upgrade to Class AA: Orbeton Stream above Toothaker Pond Rd and tributaries (Mount Abram TWP, Redington TWP, Madrid TWP, Sandy River Plt, Phillips)
  • (17) Upgrade to Class A: Schoodic and Scutaze Streams – tributaries (T4 R9 NWP, Ebeemee TWP, Lake View Plt, Brownville, Medford)
  • (18) Upgrade to Class AA: South Branch Sandy River and Cottle Brook – tributaries (TWP 6 North of Weld, Phillips)
Figure 1. Overview Map Showing Locations of Proposals for Classification Upgrades
Key Segment Current Class Proposed Class
1 Androscoggin River (below Gulf Island Pond) C B
2 Cambolasse Stream (below Rt. 2) C B
3 Chain Lakes Stream A AA
4 Donnell Pond tributaries B A
5 East and West Branch Penobscot River tributaries in Katahdin Woods and Waters National Monument A AA
6 East and West Branches Nezinscot River tributaries B A
7 Fletcher Brook and tributaries A AA
8 Houston Brook and tributaries A AA
9 Little Androscoggin River (upper) tributaries B A
10 Little Narraguagus River A AA
11 Long Creek (Westbrook) C B
12 Magazine Brook A AA
13 Medunkeunk Stream tributaries B A
14 Mount Blue Stream and tributaries B A
15 Orbeton Stream and tributaries A AA
16 Presumpscot River (below Saccarappa Falls) C B
17 Schoodic Stream and Scutaze Stream tributaries B A
18 South Branch Sandy River and Cottle Brook and tributaries A AA
19 Southwest Branch St. John River A AA
20 West Branch Penobscot River (upper) and tributaries A AA

Statutory error corrections. During the proposal review process, the Department discovered two errors in statute that it proposes to correct:

  • Correct spelling mistake in waterbody name: 38 M.R.S. Section 468.1.C.2: correct 'Finnard Brook' to 'Finnerd Brook'.
  • Correct erroneous statutory section and clarify name:
    • 38 M.R.S. Sections 467.1.B.2.d and 467.1.B.2.e: Cushman Stream and Meadow Brook in Woodstock are incorrectly listed as tributaries to the Little Androscoggin River when they are in fact tributaries to the Androscoggin River; move to Sections 467.1.D.10 and 467.1.D.11.
    • 38 M.R.S. Section 467.1.D.11: correct 'Cushman Stream' to 'Cushman Stream (unnamed tributary to Meadow Brook at Cushman Hill Road)'

DEP Review Process

The Department reviewed all proposals that were submitted, considering a number of factors. For water quality standard changes, factors included: complexity of proposal, impact on licensed dischargers (incl. hydropower facilities) or other permit holders, extent of change, relationship to other WQS, and implementation considerations. For classification changes, the following factors were considered: water quality standards attainment status, data availability and interpretation, value of waterbody as endangered species habitat (Atlantic salmon), land use in the watershed, presence of conservation land, impact on licensed dischargers (incl. hydropower facilities) or other permit holders, and classification of adjacent water bodies. Where appropriate, Department staff also ran water quality models to inform the decision-making process. Documentation containing the Department's current recommendations on all proposals, i.e. those recommended for action by DEP and those not recommended for action.

Public Input Phase

On April 26, 2021, the Department initiated the public input phase on Triennial Review proposals. At a virtual meeting on Friday, May 21, the Department provided an overview of the proposals and offered an opportunity to provide input. Presentation from meeting (pdf, 6MB)

Written comments were accepted until May 26, 2021. The Department reviewed all comments received and updated prior recommendations as necessary. A responses to comments document is available 

The Triennial Review has now concluded the major steps at the Board of Environmental Protection. The Department presented its revised recommendations to the Board at the Board’s regular meeting on August 5, 2021 in Augusta and requested that the Board schedule a public hearing. The public hearing on the revised recommendations occurred on October 7, 2021 in Augusta; participation by Zoom videoconference was enabled. The public comment period on the Triennial Review recommendations extended from August 18 through October 25, 2021. The transcript from the public hearing and collated comments received are available.  A responses to comments document is also available. A work session between the Department and Board on public comments received and revised recommendations occurred on December 2, 2021 (rescheduled from November 18, 2021). Following further deliberations, the Board amended the final recommendations and voted on final revised recommendations on December 16, 2021. A revised responses to comments document is also available. On January 4, the Board submitted the final revised recommendations and revised responses to comments to the Maine Legislature for consideration in the next legislative session.

Questions regarding the current process may be directed to Susanne Meidel.

Other Important Documentation

Related pages