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Protecting the river and public health
For decades, the Gallatin River has faced growing nutrient pollution from septic systems throughout the canyon. Studies going back to 2018 identified onsite wastewater systems as a leading contributor of nitrogen reaching the river and its groundwater, with some systems also posing direct health risks to nearby drinking wells. Recent modeling shows that replacing these individual systems with a centralized, monitored sewer system could cut nitrogen loading to the river by roughly 23% canyon-wide, and up to 41% within the project's core planning area. This isn't a theoretical benefit, it's the difference between a river that continues to decline and one with a real path toward recovery.
Why The Canyon Sewer Project Matters
Protecting the Gallatin River While Supporting Responsible Growth
The Gallatin Canyon Sewer Project is a long‑term investment in water quality, public health, and community sustainability. The project replaces aging septic systems with centralized wastewater treatment to reduce nutrient loading to the Gallatin River and its underlying aquifer, while supporting smarter development in the canyon corridor.
Gallatin Canyon is experiencing two converging challenges:
Increasing nutrient impacts
to the river and aquifer, including algae growth
Ongoing growth pressure
in an
environmentally sensitive
corridor
The sewer project addresses both by managing wastewater more effectively, protecting drinking water sources, and reducing long‑term environmental risk. The sewer will create net nutrient reduction, even with the expected growth.
“The Gallatin Canyon sewer project has the potential to be one of the most important investments we can make in the long-term health of the Gallatin River.
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By replacing septic systems with modern infrastructure, we reduce nutrient pollution at its source and protect water quality for future generations,”
- KRISTIN GARDNER
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Chief Executive and Science Officer
Gallatin River Task Force
Project Overview
The Gallatin Canyon County Water and Sewer District (GCCWSD) proposes nearly five miles of sewer collection main along Highway 191 and throughout the Canyon Area corridor. Wastewater would be collected and conveyed largely by gravity to a lift station, where it would be treated at the soon-to-be upgraded Membrane Bioreactor facility. Treated effluent would be conveyed by gravity back to the Canyon Area for disposal via groundwater infiltration or as irrigation reuse. The disposal and reuse main would extend along the entire corridor to facilitate disposal at several locations, while also serving as potential irrigation water for existing and future development.
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Details about the proposed project can be found in the Preliminary Engineering Report.
Fundamental Needs
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Infrastructure to support workforce housing that is currently extremely lacking.
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Retiring septic systems that present notable human health risks and detrimental nutrient loading to the Gallatin River.
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Addressing current disposal limitations and operational risks associated with lack of disposal redundancy.
Mission
Provide central sewer to the Gallatin Canyon corridor in order to protect the Gallatin River water quality and public health by reducing septic wastewater loading to the aquifer while facilitating higher density workforce housing and reducing resource intensive sprawl.
Project Timeline​
News & Announcements
Meetings & Agendas
Meetings are held at the Big Sky County Water Sewer District (BSCWSD) Board Room &/or via Zoom
Location: 561 Little Coyote Rd, Big Sky, MT
Preview upcoming meeting agendas and past meeting minutes here.