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Gallatin Canyon Sewer Project

The Gallatin Canyon County Water and Sewer District (GCCWSD) proposes nearly five miles of sewer 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. 

Details about the proposed project can be found in the Preliminary Engineering Report.

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Fundamental Needs
  • Infrastructure to support workforce housing that is currently extremely lacking.

  • Retiring septic systems that present notable human health risks and detrimental nutrient loading to the Gallatin River.

  • Addressing current disposal limitations and operational risks associated with lack of disposal redundancy.


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.

  • June 2019 – $12 Million BSRAD Funding

  • May 2020 – Feasibility Study

  • July 2020 – 1% for Infrastructure

  • Dec. 2020 – District formed

  • July 2021 – PER & ARPA Funding

  • Sept. 2021 – $2M ARPA Grant

  • Oct. 2021 – $750K ARPA Grant

  • Apr./May 2022 – ARPA, RRGL and MCEP grant applications and MCEP Environmental Assessment

  • 2022 to 2026 Outreach, phasing plans, permitting, design, and construction

Environmental Assessment

Prepared for the Montana Coal Endowment Program

The Gallatin Canyon County Water and Sewer District (GCCWSD) is currently preparing a grant application for $750,000 to be used for the proposed Gallatin Canyon Sewer Project. As part of that application, an Environmental Assessment (EA) is required. The intent of the EA is to provide a high-level review of potential impacts of the project on the human environment. Click here to download the preliminary report from April 2022, or here to download the final report from May 2022 which will be included in the MCEP Application.

Gallatin Canyon Sewer PER

Preliminary Engineering Report (PER)

This report presents planning and engineering required to address sewer infrastructure improvements in the newly formed district. It provides an assessment of existing environmental impacts and human health risks, analyzes alternatives for solutions, and proposes a course of action to solve to the forthcoming issues. This report utilizes the findings of previous reports, primarily the ‘Canyon Area Feasibility Study’ dated May 2020, prepared by WGM Group and AE2S, facilitated by the Gallatin River Task Force and funded by the Resort Tax Advisory Board. Click here to download the report. 

Districting Gallatin Canyon

What does it mean for the river? 

On December 29th, to little fanfare and taking no credit, the Gallatin River scored a major victory when commissioners from Gallatin County voted unanimously to approve a petition for the formation of a new Gallatin Canyon water and sewer district.

Now, you might be thinking, why should we care about a water and sewer district? What is so important about that? Click here to find out. 

Canyon Area Feasibility Study

Technical Memorandum

The Canyon Area Feasibility Study (FS) provides a preliminary evaluation of wastewater management options for the development corridor adjacent to the Gallatin River near Big Sky, Montana, Gallatin County. Detailed study findings are organized in a series of technical memorandums (TMs) addressing the overall FS scope including:  

  • District formation recommendations and guidance (TM1)

  • Review of existing and projected wastewater flow rates and associated nitrate loading to the river (TM2)

  • Sewer collection and conveyance (TM3)

  • Treatment alternatives (TM4)

  • Disposal alternatives (TM5)

  • Financial Assessment (TM6)


Click here to download the memorandum. 

Click here for information regarding funding for the district.

Cleaning up the Canyon

What does the future hold?

The Canyon area of Big Sky features some of the most beautiful stretches of water on the Gallatin River.  As this area has developed, more and more individual septic systems have came online, managed primarily by small public water operators. This decentralized approach to wastewater management has negative impacts on water quality, as nutrients from inadequately treated effluent seep into the groundwater, and then to the Gallatin River.

To protect water quality in this stretch of the Gallatin, the Gallatin Canyon Water & Sewer District was created in January, 2021. Click here for answers to FAQ's regarding the new district. 

Gallatin Canyon Wastewater Upgrade

Public Meeting

A public meeting was sponsored by the Gallatin River Task Force on March 5, 2020 to present canyon study information from consultants Mace Mangold from WGM Group and Scott Bucker from AE2S. Click here to listen in on the meeting. 

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