Revisions to Water Quality Standards from the 2025 Legislature Remain Under Federal Review
Last week, Upper Missouri Waterkeeper filed a 60-day Notice of Intent to Sue to the Environmental Protection Agency (EPA) for its failure, under the Clean Water Act (CWA) Section 303(c)(3), 33 U.S.C. § 1313(c)(3), to approve or disapprove Montana’s revised water quality standards. The agency has failed to review and act on House Bill 664, House Bill 685, and House Bill 736 – passed during the 2025 Legislative Session and signed by the Governor this spring – despite a statutory deadline requiring approval within 60 days or denial within 90 days.
“It’s been over sixty days since we petitioned the EPA to disapprove Montana’s unlawful weakening of laws to protect clean water. During this time, our rivers and streams continue to suffer from unchecked pollution and government inaction,” said Guy Alsentzer, Executive Director of Upper Missouri Waterkeeper. “The EPA’s failure to act swiftly and decisively undermines its responsibility to protect public health and the environment. We are left with no choice but to move forward with legal action to compel the EPA to fulfill its duty and protect Montana’s clean water..”
In late April, Waterkeeper advised EPA of the pending legislation and the likelihood the bills would pass. After the bills were signed, in June, Waterkeeper filed a formal rulemaking petition to the EPA calling on the agency to recognize that the “recently adopted statutory changes to the State of Montana’s water quality standards under Montana House Bill 664, House Bill 685, and House Bill 736, do not meet the requirements of the Clean Water Act,” noting that the new laws “fail to protect aquatic life, fisheries, recreational, and other existing and designated uses of Montana waters.”
House Bill 664 attempts to eliminate science-based numeric nutrient water quality criteria for undefined narrative standards. House Bill 685 would weaken nondegradation policy decisions for new or expanded pollution sources. House Bill 736 would establish an open-ended trading regime for water pollution without necessary sideboards to protect local waterway health or existing uses of rivers.
The Clean Water Act requires EPA to review and approve water quality standards before they are effective. EPA’s decision to approve must be done within 60 days. 33 U.S.C. § 1313(c)(3). Where EPA disapproves a standard it must, within 90 days, inform the state of how to correct the standard and direct the state to correct the standard within 60 days.
The 60-day NOI requests EPA fulfill its mandatory duty to act on Montana’s revised water quality standards, disapprove the revisions, and implement its own regulations setting water quality standards pursuant to Clean Water Act Section 303(c)(3) and (c)(4), because the state’s revised standards are contrary to requirements of the Clean Water Act and EPA rules.
This same issue arose in 2021 after the Montana Legislature passed Senate Bill 358, which attempted to eliminate numeric nutrient criteria and apply new, narrative nutrient standards. There, as here, EPA failed to take its mandatory action on revisions within 90 days, resulting in a lawsuit from Waterkeeper. Ultimately, EPA disapproved of Montana’s SB 358 in May 2022, reaffirming the validity of numeric nutrient criteria for all CWA purposes.
Since EPA’s May 2022 Action Letters affirming the binding nature of numeric nutrient criteria for all CWA purposes, new evidence demonstrates Montana has refused to apply numeric nutrient criteria in pretty much every instance. Most recently, DEQ denied an impairment petition for the Big Hole River and refused to apply numeric nutrient criteria in its decision-making. There is also a growing backlog of administratively continued NPDES permits with nutrient effluent limits, and DEQ has failed to issue pending TMDL restoration plans or biannual Integrated Reports, which require nutrient assessments, since 2022. While DEQ continues to avoid implementing numeric nutrient criteria, pollution problems in Montana’s waterways worsen; it’s urgent that EPA immediately disapprove of Montana’s revised water quality standards.
Yesterday’s 60-Day Notice of Intent to Sue sends a clear message that EPA must follow the law and exercise its authority to take formal action on Montana’s unscientific rollback of clean water protections. Waterkeeper believes that this issue can and should be resolved without litigation only if EPA complies with the CWA and promptly denies the offending water quality revisions.