The Environmental Protection Agency (EPA) has issued a draft of the 2025 national pollutant discharge elimination system (NPDES) drinking water general permit (DWGP) for wastewater discharges associated with drinking water treatment plants for a specific region of the U.S. that cover six states and 28 tribal nations.

According to the Federal Register notice posted on June 3, 2025, the Clean Water Act (CWA) directs a DWGP to provide coverage for discharges of wastewater from drinking water treatment processes

The Federal Register notice entitled “Proposed Re-Issuance of National Pollutant Discharge Elimination System General Permit for Wastewater Discharges Associated With Drinking Water Production Located in the EPA Region 8 Indian Country and Lands of Exclusive Federal Jurisdiction” says the EPA is seeking comments on the draft of the 2025 NPDES, with July 18, 2025 set as the deadline to file such comments.

EPA Region 8 covers Colorado, Montana, North Dakota, South Dakota, Utah, Wyoming, and the tribal nations, some of which have CWA certification authority. Those tribes are:  

• The Assiniboine and Sioux Tribes.
• The Confederated Salish and Kootenai Tribes.
• The Northern Cheyenne Tribe.
• The Ute Mountain Ute Tribe.
• The Southern Ute Indian Tribe.

However, the EPA has requested documentation from each of those tribes that certify their DWGP complies with the applicable provisions of the CWA, and their respective tribal water quality standards.

The notice says the DWGP provides coverage for discharges of wastewater from drinking water treatment processes. Process flows contributing to the wastewater discharge include: filter backwash; filter to waste; decanted lime sludge dewatering; influent screen backwash and/or miscellaneous wastewater sources associated with drinking water facility operation; and miscellaneous wastewater sources that might include, but are not limited to processed potable water; disinfection of treatment plant pipelines and tanks; and overflow from holding tanks of treated water.

Furthermore, the DWGP also contains two sets of effluent limitations: primary effluent limitations that apply to all discharges, and supplemental effluent limitations that will apply to discharges on an individual basis as necessary to protect water quality. A full description of the geographic scope of coverage is included in the public notice version of the permit.

Under the DWGP process, the EPA will review a facility’s notice of intent for it to be covered under the DWGP as well as to determine the need for implementation of the supplemental effluent limitations and corresponding self-monitoring requirements, the notice says. The permittee will be notified of the applicable effluent limitations and monitoring requirements in the notification of coverage, the notice says.

In addition, the EPA has identified drinking water treatment processes methods that do not qualify for coverage under the DWGP. The wastewater processes not included in the general permit include batch regenerated potassium permanganate iron removal; sodium zeolite softening; and nano filtration and reverse osmosis. A full description of the geographic scope of coverage is included in the public notice version of the permit.

This is at least the second document on NPDES permits for wastewater discharges issued by the EPA since the Supreme Court’s decision in the case “City and County of San Francisco v. EPA,” which was focused on the levels of pollutants in water discharges by entities holding a NPDES permit. The court issued its decision in that case on March 4, 2025, ruling in favor of the plaintiffs saying the EPA did not articulate what actions a permittee must take, or refrain from taking, that would guide permit holders on water discharges.

As a result of that court decision, on April 15, 2025 the EPA issued a document outlining changes to its “Construction General Permit” called “Modification to 2022 National Pollutant Discharge Elimination System (NPDES) Construction General Permit (CGP) for Stormwater Discharges from Construction Activities.”

The deadline to file comments on the DWGP draft document with the EPA is on or before July 18, 2025, and all submissions must include the Docket ID No. EPA–R08–OW–2025–0010. Comments can be sent by the following methods:

• Federal eRulemaking Portal: https://www.regulations.gov. Follow the online instructions for submitting comments.
  
  
• Mail; send hardcopy comments to Wastwater Program, Environmental Protection Agency, Region 8, 1595 Wynkoop St., Denver, Colo. 80202-1129.

Comments received may be posted without change to https://www.regulations.gov, including any personal information provided. For further information, contact Paul Garrison, Wastewater Program, U.S. Environmental Protection Agency, Region 8, Mailcode 8WD–CWW, 1595 Wynkoop St., Denver, Colo. 80202–1129, telephone number: (303) 312–6016, email address: garrison.paul@epa.gov.