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Frequently Asked Questions

What is a Water Sewer District?

A County Water Sewer District is a form of local government responsible for their publicly owned water and wastewater services. More information can be found on the Montana Code Title 7 Chapter 13 Part 22 and Part 23 regarding county water and/or sewer Districts. 

What is the proposed project?

Nearly five-miles of sewer collection main is proposed along Highway 191 and throughout the existing Canyon Area development corridor. Wastewater will be conveyed largely by gravity to a Canyon Area Lift Station and forcemain which would bring Canyon Area wastewater to the Big Sky WRRF for treatment at the soon-to-be upgraded and expanded Membrane Bioreactor (MBR) facility. The BSCWSD treatment upgrade is part of another project that is already funded and construction underway. Wastewater will be screened, de-gritted, and then treated through a series of anaerobic/anoxic/aerobic zones to maximize biological nutrient removal. Biosolids will be aerobically digested, dewatered, and composted with sawdust and coarse green waste.


Treated GCCWSD effluent and a portion of BSCWSD’s effluent would be conveyed by gravity back to the canyon for disposal via groundwater infiltration or as irrigation reuse. The disposal and reuse main is planned to be extended along the entire service area corridor to facilitate disposal at a number of groundwater recharge locations while also serving as potential irrigation water for existing and future development.


Depending on funding and property owner interest in annexing into the District, the project may be built in phases.

How can I participate in the process?

The best way to be involved is to attend District Board meetings which are held quarterly. Check the Home page for the next meeting date and agenda. Public comment can be provided at public meetings or submitted written at any time.

Who can join the District?

A property, or group of properties, that is adjacent to the existing District is eligible to petition the board for annexation. Properties that are adjacent or not may request to be annexed through a petition and vote of the qualified electors of the District.


Properties included in the 2021 Preliminary Engineering Report’s “Sewer Service Area” are actively encouraged to join the District to maximize economies of scale, public health, environmental, and development benefits.  Other properties further along the canyon or along Highway 64 were not included in the preliminary design may still petition for annexation.

How can I join the District?

Annexation can be accomplished by a petition of contiguous owners who would like to join or through a vote. The District board can accept or reject a petition or establish a vote, if needed.


The District is encouraging other properties in the canyon to join and will help facilitate annexation where feasible.  If you would like to discuss possibly joining the District, please email


See the Montana Code 7-13-2341 for details. 

Why does the Canyon need a sewer?

The DEQ does not currently require centralized treatment. However, trends in nitrate loads to the aquifer in the Canyon Area coupled with additional growth in the area do point to a need to improve wastewater management in the Canyon Area. A central sewer will help protect public and environmental health by reducing pollutant loading which protects water quality in the aquifer as a source of drinking water and as a tributary to the Gallatin River. By disposing of some BSCWSD effluent, the proposed project will also reduce nutrient loading to the impaired West Fork watershed.


For more details, please see Section 3 of the Preliminary Engineering Report.

How will this be paid for?

The Gallatin River Task Force, BSCWSD, and Resort Tax District have paid for much of the planning done to date. The vote to increase the Resort Tax by 1% has helped secure $12 million for the proposed sewer project. The District is working to secure as much grant and low-interest loan funding as they can. ARPA grants and SRF loans are currently being pursued, but other funding options will be explored as well.


Grants do not need to be repaid, but loans would be paid back by District members, usually over the course of 40 years.


Unlike the infrastructure development, operations and maintenance (O&M) are not eligible for most public funding options. Monthly sewer bills, charged roughly proportional to use, will cover ongoing O&M after an initial subsidized start up period. Sewer rates have not been developed yet as they are strongly dependent on number of properties in the District.

How much will this cost me? When?

Monthly sewer bills, charged roughly proportional to use, will cover ongoing operations and maintenance (O&M) after an initial subsidized start up period. Sewer rates have not been developed yet as they are strongly dependent on number of properties in the District. In most cases, more connections will lead to lower user rates.


Debt repayments will be spread across users over time. This amount will depend on the funding package secured, bonding strategy, and number of users in the District.


These costs will not be incurred until your property is connected to an operational sewer. Currently, the project is projected to be completed in 2025.

What happens to costs if more people are in a District?

The costs per person, resident, or business generally go down as more customers join a District. This is referred to as economy of scale and is significant in public works infrastructure. The public health, environmental, and development benefits also increase as more properties are sewered.

What happens to the rest of the Canyon area?

Joining the District and connecting to centralized sewer will not be the best option for all properties and not all properties that apply for annexation will be admitted. Some properties, may have to connect to adjacent sewer lines upon failure of their onsite wastewater treatment systems per Administrative Rules of Montana (ARM) 17.36.914 and 17.36.328, even in they are not in the District’s boundaries at the time.


Private wastewater service issues are not under the jurisdiction of the GCCWSD. There are decentralized options that can provide significantly better nutrient and pathogen reduction than the current systems that could be used to treat wastewater from more remote clusters of development. SepticNet and Treatment Wetlands (similar to Bridger Bowl’s system) are promising options for these areas. Projects such as these would be the responsibility of the property owners.

What is the current nitrogen load from septic and community systems?

It is currently approximately 4,600 pounds per year and is projected to be as much as 12,000 pounds per year if growth continues and wastewater management methods do not improve.

How much is the projected overall cost?

Table 6.5.1 provides a summary of the opinion of probable “total project” cost for a collection system for each service area. Total project costs are defined as the sum of planning, engineering, construction and construction administration.


The conceptual opinion of probable project cost was developed based upon previous project data, project specific equipment quotes, and RS Means cost estimating manuals. This cost opinion represents a Class 4 Estimate based upon the definitions of the Association for Advancement of Cost Engineering (AACE) International. This level of cost opinion is appropriate for planning level evaluations made with incomplete information.  The cost opinion at this level of engineering is considered to have an accuracy range of +50/-30 percent.  Actual costs will not be determined until a public bidding process has been completed. Escalation should be applied to the year of construction, but the ultimate schedule is unknown at this time.

Will the project address nitrate issues in surface water?

Yes. According to modeling and stream flow data, the Canyon Study Area septic systems cause nutrient concentrations to roughly double in the adjacent stretch of the Gallatin River during baseflow. The Upper Gallatin River is not currently listed as impaired for nutrients, but elevated levels are present, and it has experienced algal blooms in recent years. With projected growth and continued installation of onsite systems-based wastewater management, septic-related nitrogen loads to the Gallatin River would approximately double in the next 20 years. A major outcome of the project will be reduced nutrient loading to the Gallatin River by replacing aging septic systems with a centralized sewer collection and treatment system that treats to Class A1 effluent quality. Additionally, nutrient loading to three 303(d)-listed tributaries in the West Fork of the Gallatin and the associated riparian areas will be greatly reduced by moving some of BSCWSD’s effluent out of the watershed, for groundwater disposal in the GCWSD. It is estimated that enough nutrients could be removed to meet the West Fork’s Nitrate+Nitrite and Total Nitrogen TMDLs.

Will this affect growth issues?

Yes. Wastewater flows and population are expected to grow to nearly 2.7 times the current level in the planned sewer service area in the next 20 years. The current GCCWSD is projected to grow to 5.4 times present levels during the same period.  The area suffers from lack of workforce/affordable housing, and the Canyon Area development model of individual wells and septic systems results in inefficient land use (e.g. development sprawl). One current example, is a new high-density development waiting in limbo that would provide 265 living units, including some designated ‘affordable housing’. Centralized sewer and wastewater treatment is expected to promote infill and redevelopment of underutilized land parcels. In addition to reducing the environmental, health, and administrative burdens of individual septic use, this should help alleviate other current community challenges such as commuter traffic congestion from workforce/affordable housing in the Gallatin Valley, and its related pollution.

Is there any cap on growth in the Canyon area?

Water rights limit the total feasible growth in the Canyon. The Gallatin watershed is a closed basin and senior water rights holders are downstream. Growth in this area of the Canyon is likely capped at approximately three times the existing development.

How much will this cost me?

Costs to users are still highly variable. The financial Tech Memo of the 2020 Feasibility study estimated a $70/month domestic user rate and a $10,000 connection residential connection fee. Current user rate estimates range from $100-$200/month. The District is working hard to keep the costs fair and affordable. More firmly defined costs to users will be available in coming months.

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