Standards and Requirements

Applicable Codes and Regulations

The Big Sky County Water & Sewer District No. 363 follows the Uniform Plumbing Code (UPC) 2021, as adopted by the State of Montana through the Montana Plumbing Code (2021), including all local amendments and additions.

Fire code regulations are governed by Montana Code Annotated (MCA) §§ 7-33-2205 and 7-33-2206.

Project Requirements

All projects within the District must meet the requirements of the applicable codes listed above and comply with the District’s Standard Specifications and Standard Drawings, where applicable. For project-specific questions or plan reviews, please contact the District Office to schedule a meeting.

Drawings Availability

The District no longer releases drawings associated with its Standard Specifications except by request. All drawings are currently undergoing updates. Requests for drawings should be submitted to office@wsd363.com.

Water and Sewer Main Extensions

Developers and contractors proposing to extend water or sewer mains must design, construct, and test improvements according to the District’s Standard Specifications and Drawings.

Key Requirements

• Design Approval: All main extensions require District review and approval before construction.
• Materials & Installation: Only materials meeting District standards, the DEQ circulars , and AWWA specifications are acceptable.
• Hydraulic & Capacity Design: Extensions must maintain minimum operating pressures and flow consistent with District performance criteria.
• Construction & Inspection: All extensions must be inspected prior to backfill. Pressure testing, leakage testing, and disinfection must meet District standards.Ownership & Acceptance: Upon inspection and approval, mains may be accepted for ownership and maintenance by the District.

Note: The District no longer publishes or endorses a public “Approved Parts List.” All material selections must meet the performance and specification criteria outlined in the applicable plumbing and fire codes.

Fire Suppression

Fire Suppression Engineers
The Big Sky water system covers a large area with significant elevation differences, resulting in substantial variations in working pressures between zones. Because the system continues to expand, many areas that currently receive water service have not yet reached their final hydraulic design configuration.

As the District grows and new service areas are looped into existing mains, pressures may be reduced to balance adjoining zones. Consequently, areas that currently exhibit high pressures and robust fire flows may experience lower pressures in the future as the system stabilizes.

To ensure accurate system design and prevent under-sized fire suppression systems, the District will not provide temporary or transient fire flow data that may overstate long-term conditions. Instead, fire suppression system engineers will be provided with the permanent minimum design criteria applicable to the Big Sky water system.

Minimum Design Values
Based on the Fire code regulations adopted by the State of Montana and the Big Sky Fire Department IFC 2021.

Engineers must verify that their project location meets or exceeds these minimum values before design. Some older developments may not meet the minimums; it is the responsibility of the fire suppression engineer to confirm current pressures and flows by contacting one of the District’s water operators.

Coordination and Design Review

• Fire flow design and pressure verification shall align with the Big Sky Fire Department’s code adoption and requirements.
• All fire suppression systems will be reviewed and analyzed through the District’s engineering water model to confirm design criteria and compliance prior to approval.
• The District reserves the right to require hydraulic modeling or documentation demonstrating that system impacts have been properly evaluated.
• Fire suppression systems must comply with Montana DEQ, NFPA, and District Standard Specifications.

Backflow Prevention and RP Device Standards
The District requires backflow prevention devices on all services to protect the public water system from contamination.

Requirements

• All backflow preventers must be lead-free and meet ASSE 1024 or ASSE 1013 (RP) standards, as applicable.
• Reduced Pressure (RP) backflow assemblies are required for residential, commercial, industrial, or multi-use properties, and any use where cross-connection potential exists.

Installation

• Backflow devices must be installed in horizontal configuration and remain visible and accessible for inspection.
• Downstream shut-off valves are not accepted as part of the assembly.
• All installations must comply with the District’s Standard Drawings and Montana Department of Environmental Quality (DEQ) regulations.

Inspections and Scheduling

All water and sewer installations must be inspected and approved before backfilling. To schedule an inspection, contact the District Office at least two business days in advance. Specifications and standard drawings are available by request at office@wsd363.com.