by Michael Howell
The Upper Missouri Waterkeeper, Flathead Lakers and the Confederated Salish and Kootenai Tribes filed a lawsuit in January 2026 challenging the Environmental Protection Agency’s (EPA) approval of Montana’s repeal of science-based, numeric water quality standards for nitrogen and phosphorus. The suit argues that replacing these standards with “vague, unenforceable” rules (via HB 664) violates the Clean Water Act (CWA) and threatens Montana’s water quality, fisheries, and public health.
The Montana Department of Environmental Quality (MDEQ) submitted HB664’s revision of nutrient criteria to EPA for review by letter dated May 6, 2025, just one day before adopting the changes, which require EPA approval according to federal law.
This prompted Upper Missouri Waterkeeper to petition EPA to conduct rulemaking, disapprove HB664 for CWA purposes, and impose all necessary nutrient water quality standards based on best available science, by letter dated June 4, 2025. But on October 3, 2025, EPA issued an “Action Letter” approving HB664.
Most states, including Montana, used “narrative standards” involving observation of such things as algae blooms, degraded fisheries, and unsafe drinking water to determine when a waterbody was “impaired.” In 2014, Montana adopted numeric standards for determining when a wadable stream was impaired for nutrients, one of the first states to do so. This provided a science-based numerical criteria for declaring a waterbody impaired with a high degree of accuracy and in time to take corrective action to prevent the growth of harmful algae blooms and degraded fisheries, degradation that is often difficult and costly to reverse.
Since that time, according to MDEQ’s latest Water Quality Integrated Report which assessed the water quality in 23,111 miles of perennial streams – almost half the streams in Montana – and 521,088 acre feet of water in lakes and reservoirs – about three quarters of the lakes under state jurisdiction – it was found that 68,354 acres of lakes (13%) and 5,066 miles (22%) of the state’s assessed rivers and streams are impaired for nitrogen and 73,324 acres (14%) of the lakes and 5,349 miles (23%) of its assessed rivers are impaired for phosphorous.
Upper Missouri Waterkeeper Guy Alsentzer told the Bitterroot Star that the number one thing he would say is that, “The federal government is supposed to be the backstop to rein in states to use science to tell how we protect fishable, swimmable, drinkable water. The problem here is that EPA is not doing its job to use science to inform the goal posts for waterway protection and restoration.”
“Montana’s rollback of numeric standards is unprecedented,” he said. “Never before, in the 53-year history of the Clean Water Act, has a state adopted strong, science-based numeric nutrient standards and then reversed course due to political pressure from polluting industries. EPA doesn’t get to rubber-stamp the State of Montana’s illegal water quality rollbacks for polluters and pretend there is no risk. The law requires agencies to understand how gutting water pollution control standards would impact the state’s clean water resources, including threatened and endangered species, before making a decision. EPA didn’t do their homework before hastily approving the state government’s giveaway to polluters.”
According to Coby Gierke, Executive Director of Flathead Lakers, the decision to adopt numerical nutrient standards was based on decades of science demonstrating clear links between nutrient pollution and algal blooms, degraded fisheries, and unsafe drinking water.
“Clean water is the backbone of the Flathead watershed; it sustains our economy, our communities, and our way of life. It is not worth risking the famously clean waters of the Flathead — waters that generations of Montanans have relied on for drinking, swimming, fishing, and cultural connection — so that polluters can more easily meet regulatory requirements,” it stated in the group’s press release.
MDEQ Director Sonja Nowakowski stated before the House Natural Resources Committee last February that, “House Bill 664 outlines one of my favorite things that the legislature is able to do … and that is time travel. We are going back in time. This bill repeals the numeric criteria but it returns us to the 2013 processes that recognize and retain the flexibility of 30 years of science done by DEQ’s highly qualified staff.”
The Montana legislature’s first attempt at “time travel” in 2021, Senate Bill 358, was a failure. Adopted prior to EPA approval, when it was reviewed EPA rejected the changes because eliminating the numeric criteria and leaving on narrative criteria was done, “without adequate information to demonstrate that the narrative criteria alone protects the designated uses.”
The current lawsuit argues that current reversal of course by the EPA suffers from the same deficiency.
In its recent letter of approval, EPA references “a wealth of new information that the state could use to translate the narrative criteria for CWA implementation purposes.” But plaintiffs argue that, “The alleged new science and analyses were not submitted as part of the package under 40 C.F.R. § 131.6 and could not have been properly submitted because they were never codified.” MDEQ initiated a nutrient monitoring group composed of scientists, conservation organizations, municipalities and industrial users to help design rules for implementing the vague narrative regulations currently on the books; those efforts floundered for years and were eventually closed down.
Plaintiffs also claim that although the state has initiated consultation with the U.S. Fish and Wildlife Service to ensure that its changes to nutrient criteria do not jeopardize the continued existence of endangered and threatened species or destroy or adversely modify designated critical habitat, that has not been completed.
Plaintiffs are requesting the Court to determine and declare that EPA’s October 3, 2025 approval of Montana’s elimination of numeric nutrient standards is arbitrary, capricious, and otherwise not in accordance with law. They are also seeking a declaration that it violates the Endangered Species Act because EPA failed to complete consultation as required prior to approving the revision and because EPA made an irreversible or irretrievable commitment of resources by approving the changes after initiating but before completing consultation.
They ask the Court to enter an order vacating and setting aside EPA’s October 3, 2025 approval of Montana’s revised nutrient water quality standards and direct EPA to complete consultations with the U.S. Fish and Wildlife Service and to finalize federal water quality standards for nutrients in Montana that comply with the Clean Water Act within a reasonable time period.
Leave a Reply