Lawsuit Seeks to Hold Government Accountable for Ignoring Public Participation and Environmental Review of Major Water Infrastructure Project
Today, Upper Missouri Waterkeeper announced a lawsuit against the Montana Department of Environmental Quality (DEQ) for its approval of a major new sewer pipeline in Big Sky without any public processes, as is afforded citizens in the Constitution, and for failing to conduct necessary environmental review under the Montana Environmental Policy Act (MEPA) for a project critical to water quality in the Gallatin River.
“Massive infrastructure projects being approved behind closed doors, without public participation, is antithetical to democracy,” said Guy Alsentzer, Executive Director of Upper Missouri Waterkeeper. “DEQ is stacking the deck by considering pieces of a regional wastewater system in isolation. The public deserves – and the Montana Constitution guarantees – a transparent decisionmaking process that reviews the whole picture. DEQ knows well a Big Sky sewer pipeline is integral to a pending new municipal-scale discharge permit application, yet the public is being shut out of any meaningful public participation on critical sewage infrastructure decisions. This is wrong and illegal.”
The lawsuit was filed following the 30-day deadline for the public to file a legal challenge from when they know, or should have known, that the government has failed to provide public notice or participation opportunities on a matter of significant public interest. In this case, Waterkeeper learned of DEQ’s June 2025 sewer pipeline approval through a Right to Know Request that was fulfilled in mid-November 2025. Among the documents disclosed by the agency was an extensive record of years of dialogue between DEQ and local sewer districts about what has been called the Gallatin Canyon Sewer Project.
The Pipeline Project is self-described in the application as a first and essential component of the Gallatin Canyon Sewer Project. The Pipeline Project entails approximately 5,000 feet of two pipelines – a sewage line and a treated effluent line – from a primary lift station and a secondary lift station, adjacent to Highway 64 and running parallel to reaches of the West Fork Gallatin River. The Pipeline Project’s application to DEQ explicitly describes the Project’s purpose as: serving sewage collection in Big Sky’s Canyon Area; a sewage conveyance structure up to Big Sky’s Meadow Area for wastewater treatment by the Big Sky County Water & Sewer District; and conveyance of treated wastewater back to the Canyon Area for disposal through a related groundwater discharge permit, sought by the Gallatin Canyon Water & Sewer District and currently being considered by DEQ.
Key Issues Challenged in the Lawsuit:
- Violation of public participation rights: The approval of the pipeline was done entirely behind closed doors, denying the public and stakeholders any notice, much less a voice, on a project of likely significant public interest and major consequences for the Gallatin River and downstream water users.
- Failure to Conduct a Comprehensive Environmental Review: DEQ also failed to perform any MEPA review for the Pipeline Project, much less a holistic review of the Gallatin Canyon Sewer Project, despite their self-proclaimed interdependence and the fact that DEQ was concurrently reviewing multiple project elements. The failure to perform any MEPA appears to be based on the agency’s illegal pattern and practice of determining any infrastructure project compliant with engineering standards (under DEQ Circular 2) is automatically exempt from MEPA review. However, the 18th Judicial District has recently held in two analogous cases that MEPA applies to DEQ decisions, including so-called infrastructure decisions.
- Connected Actions Ignored: The pipeline is not a standalone engineering decision; it is an inseparable part of a larger connected regional wastewater conveyance and disposal system that must be reviewed as a whole. The Right to Know Request produced by DEQ proves the agency is currently evaluating a municipal-scale discharge permit application from the Gallatin Canyon County Water and Sewer District for new wastewater disposal at various locations in the Canyon Area. The lawsuit demands that the agency hit pause on the Pipeline Project and require a full environmental review of the entire project, with robust public participation, to fully understand the consequences of this generational investment in water infrastructure.
Additional Issues with the Pipeline Project:
- Inadequate Wastewater Treatment – The new membrane bioreactor in Big Sky is treating wastewater to Level A-1 nutrient concentrations, an antiquated treatment standard in Montana’s pollution control rules. There is no peer-reviewed science demonstrating that injecting hundreds of thousands of gallons of class A-1 wastewater each day into the canyon’s groundwater will assure protection of the Gallatin River or stop the recurring algal blooms. Waterkeeper fully supports centralized, highest-level wastewater treatment and addressing legal septic contamination from sprawl development, but presuming a new discharge permit adjacent to the Gallatin is safe is both unproven and fool-hardy.
- The Gallatin River is Impaired – The Gallatin River is already designated as impaired by algal blooms. Algal blooms are caused and contributed to by nutrient pollutants contained in wastewater. Even individually small amounts can, together, cause harm and be a part of the problem. Without an EPA-approved clean up plan for the Gallatin, a new pollution discharge permit adjacent to the Gallatin is inappropriate.
- Adverse Downstream Impacts – The additional nutrient pollution from the Pipeline Project is likely to negatively impact thousands of downstream users in the Gallatin Valley that rely on clean water for drinking, agriculture, businesses, and recreation.
Big Sky has the potential to be a model mountain resort community that ensures it does not degrade water quality. Presently, the Gallatin Canyon Sewer Project has not demonstrated it is rising to the high bar of guaranteeing protection of the Gallatin’s water quality. Any regional wastewater infrastructure plan should comprehensively address how proposed plans will transform a growing wastewater liability into an asset, reduce existing pollution, restore degraded water quality, and ultimately address both water supply and water quality constraints.
The critical first step in developing the Gallatin Canyon Sewer Project must be a comprehensive environmental impact statement under MEPA that fully evaluates the impacts of a regional wastewater infrastructure project and ensures an open, transparent public process that meaningfully considers community input, concerns, and alternatives.
The lawsuit’s penultimate focus is therefore twofold:
First, to correct DEQ’s unlawful pattern and practice of making engineering decisions for critical sewage infrastructure behind closed doors and without public participation or MEPA review.
Second, to hold DEQ accountable to properly apply constitutional environmental protection imperatives underlying MEPA by considering and evaluating regional sewage infrastructure projects as a whole, with public participation, before decisions are rendered.