An official website of the United States government.

This is not the current EPA website. To navigate to the current EPA website, please go to This website is historical material reflecting the EPA website as it existed on January 19, 2021. This website is no longer updated and links to external websites and some internal pages may not work. More information »

Federal Water Quality Standards Applicable to Maine

In December 2016, EPA issued final federal Clean Water Act water quality standards (WQS) that apply to water bodies under the state of Maine’s jurisdiction. These WQS included human health criteria (HHC) for 96 toxic pollutants to protect a now-withdrawn sustenance fishing designated use in waters in Indian lands and a phenol criterion to protect human health from consumption of water plus organisms in waters outside of Indian lands in Maine.

On August 13, 2020, EPA proposed to withdraw these HHC following its approval of replacement criteria submitted by the state that protect applicable designated uses.

On this page:

Final Rule

In December 2016, EPA promulgated HHC for 96 toxic pollutants for waters in Indian lands and six additional WQS for waters in Indian lands:

  • Recreational and shellfishing bacteria criteria to protect human health;
  • Tidal temperature, pH, and ammonia criteria to protect aquatic life;
  • A mixing zone policy; and
  • Clarification that natural conditions provisions cannot be applied to HHC.

EPA also promulgated two WQS for all waters in Maine including waters in Indian lands:

  • Dissolved oxygen criteria for Class A waters to protect aquatic life; and
  • Clarification that the Clean Water Act does not allow the commissioner of the Maine Department of Environmental Protection to waive compliance with WQS in case of oil spills.

Finally, EPA promulgated one WQS (phenol criteria to protect human health) for waters in Maine outside of Indian lands.

These federal WQS address various disapprovals of Maine’s standards that EPA issued in February, March, and June 2015.

Top of Page

Withdrawal of Certain Federal Water Quality Criteria Applicable to Maine

On December 3, 2020, EPA finalized the withdrawal of certain existing federal water quality criteria - clearing the way for Maine to implement its human health water quality criteria for toxic pollutants. This final action follows Maine’s adoption of human health criteria that EPA determined are based on sound science and protective of the State’s designated uses. The withdrawal of existing federal criteria enables Maine to implement those EPA-approved human health criteria.

Public Hearings

EPA offered two online public hearings so that interested parties could provide oral comments on EPA's proposed rule.

Comments on the Proposal

The comment period closed on October 19, 2020.

Top of Page

You may need a PDF reader to view some of the files on this page. See EPA’s About PDF page to learn more.