Montana, a state celebrated for its pristine natural beauty, including its abundant waterways, high-alpine lakes, and world-renowned trout streams, now finds itself at a crossroads concerning environmental protections for these vital resources. The state is the birthplace of major rivers like the Missouri and is home to Flathead Lake, the largest natural freshwater lake west of the Mississippi River. However, recent legislative actions, with the Environmental Protection Agency’s (EPA) approval as of October, signal a significant rollback of protections for these invaluable aquatic ecosystems.

Historically, Montana has been a frontrunner in regulating water pollution. In 2014, it became the first state in the nation to implement numeric water-quality standards for dissolved nitrogen and phosphorus in wadable streams and certain river segments. These nutrients, often originating from mining operations, municipal wastewater discharges, and agricultural runoff, are key drivers of nutrient pollution. When present in excessive amounts, they can fuel rapid algal growth, leading to a cascade of detrimental environmental effects. These slimy green blooms not only mar the aesthetic appeal of waterways but also deplete dissolved oxygen essential for aquatic life, potentially causing widespread fish die-offs. Furthermore, dense algal mats can block sunlight from reaching deeper waters and release toxins that pose serious health risks to humans and animals ingesting contaminated water.

Water-quality standards, as defined by the EPA, are crucial objectives set by states and tribes to ensure their waters are safe for both human consumption and the sustenance of aquatic life. These standards guide a state’s environmental policy, influencing everything from the mobilization of cleanup efforts to the issuance of permits for point-source polluters—entities that discharge wastewater through pipes or ditches. Water-quality standards can be established either numerically, by setting precise upper limits for pollutants before adverse effects manifest, or narratively, by describing the desired condition of clean waterways based on observable degradation parameters.

This year, however, a trio of bills passed by the Montana Legislature repealed the state’s numeric nutrient standards, reverting to existing narrative standards. Environmental advocacy groups and water-quality experts widely consider narrative standards to be less protective than their numeric counterparts. The fundamental difference lies in their preventative capacity: numeric standards act proactively, compelling polluters to treat their waste before any noticeable degradation occurs. In contrast, narrative standards are typically invoked only after water quality has already deteriorated, making them reactive rather than preventive. Numeric standards offer quantifiable and therefore enforceable benchmarks for maximum pollution levels, whereas narrative standards are more subjective, granting greater discretion to both polluters and regulatory bodies.

The shift to narrative standards has introduced considerable uncertainty regarding their practical implementation. Scott Bosse, the Northern Rockies regional director for the nonprofit American Rivers, highlighted this ambiguity, noting that it remains unclear how Montana’s Department of Environmental Quality (DEQ) will officially enact these new regulations. The DEQ, however, maintains that narrative standards can be a more efficient approach to pollution prevention. The department plans to evaluate each water body on a case-by-case basis, tailoring anti-pollution strategies to the unique hydrological and ecological characteristics of the local environment.

Andy Ulven, chief of the DEQ’s Water Quality Planning Bureau, stated that the department is "really trying to find the best site-specific controls." Under the revised framework, the DEQ will rely on indicators such as the health of sensitive aquatic species, like mayflies, the prevalence of algal growth, and dissolved oxygen levels to inform water policy. While dissolved nitrogen and phosphorus will still be considered, Ulven emphasized the need to "look at the bigger picture" to ensure effective water management.

Critics, however, remain unconvinced, arguing that the 2025 legislation is vague and overly broad. Nine environmental watchdog groups have publicly called for a moratorium on wastewater discharge permits until a more concrete plan for implementing the narrative standards is established. This request stems from concerns that without clear guidelines, the permitting process could become less rigorous, potentially exacerbating existing pollution issues.

This is not the first attempt by Montana to dismantle its numeric nutrient standards. The EPA previously rejected similar proposals in 2020 and 2022, citing concerns that the proposed changes would violate the Clean Water Act. This year, however, the agency made an abrupt policy reversal, approving the new rules on October 3rd, coinciding with a period of government shutdown.

Despite establishing numeric criteria for nutrient pollution in 2014, Montana had not consistently enforced them. Instead, the DEQ frequently extended existing permits without requiring upgrades to meet the new standards. Currently, over two dozen permit renewals are pending, affecting major urban centers like Billings and Missoula, as well as towns such as Kalispell and Whitefish, whose waters flow into the ecologically significant Flathead Lake.

The implementation of the previous numeric standards would have necessitated substantial investments in upgrading the state’s generally outdated wastewater treatment infrastructure. Guy Alsentzer, executive director of Upper Missouri Waterkeepers, argued that such upgrades are crucial for the long-term health of Montana’s waterways and the well-being of its residents. He acknowledged the financial challenges, stating, "Nobody wants to pay for it," but underscored that "you don’t mess with your goalposts if you have an implementation problem."

Compounding these concerns, over 35% of Montana’s river miles and 22% of its lakes are officially designated as impaired due to pollution from sewage, industrial waste, and agricultural fertilizers. Environmental organizations fear that issuing a new wave of permits under the relaxed narrative standards could effectively open the floodgates to further nutrient contamination.

Since the approval of the new standards on October 3rd, Montana has advanced only one new permit renewal. This permit is for the Sibanye-Stillwater platinum and palladium mine, situated along the East Boulder River in the southern part of the state. The mine’s original 2023 permit imposed strict numeric limits on nitrogen pollution, a byproduct of dynamite usage, which the company was to meet within a decade. However, the revised permit, still undergoing the approval process, permits a more than fifty-fold increase in the amount of nitrogen the mine operators can release. This case is being closely watched as a significant test case for how rivers will fare under the new narrative standard regime.

Montana’s decision to weaken its water-quality standards occurs amidst a broader trend of increased challenges to the Clean Water Act nationwide. Recently, federal proposals have aimed to remove federal protections from a substantial portion of the nation’s wetlands, further signaling a shift in environmental regulatory priorities.

As federal environmental protections are being scaled back, critics argue that states should be intensifying their efforts to safeguard their natural resources. Montana’s successful repeal of its stricter pollution standards is likely to embolden other states to pursue similar rollbacks, especially given the EPA’s apparent receptiveness. "One of the take-home messages here is that the states will see EPA as receptive to these rollbacks of Clean Water Act protections," commented Andrew Hawley, a staff attorney at the Western Environmental Law Center.

Consequently, Montana’s waterways are becoming increasingly vulnerable to pollution. Scott Bosse of American Rivers expressed dismay at the decision, stating, "It’s so mind-boggling to me that both the state and the EPA would want to put Montana’s clean water at risk by shifting to narrative standards. We’re basically slitting our own throat." The long-term implications of this regulatory shift for the state’s iconic aquatic ecosystems and the communities that depend on them remain a significant concern.