Commerce City, CO Building Safety: Fire Sprinkler Requirements (2026)

Commerce City Revised Municipal Code § 5-4201 amends the 2021 International Residential Code (IRC) as adopted for the City of Commerce City Residential Code. Section R313.1 states that an automatic sprinkler system shall be a required builder-provided option in all new townhouses, and the parallel Section R313.2 imposes the same builder-provided-option requirement on all new one- and two-family dwellings; neither section mandates that the homeowner actually accept the system, only that the builder offer it. Additions or alterations to an existing townhouse or dwelling that was not already sprinklered are excepted from the requirement in both sections.

Where a buyer opts in, Sections R313.1.1 and R313.2.1 require the system to be designed and installed under Section P2904 of the residential plumbing provisions, which governs stand-alone and multipurpose wet-pipe systems, minimum three-quarter-inch supply piping and prohibits antifreeze additives in the water supply. The sprinkler choice also carries a design payoff elsewhere in the code: Section R302.3 lets the one-hour fire-resistance rating between two-family dwelling units drop to a half hour where the building is sprinklered under Section P2904, and Section R324.6.2.1 relaxes rooftop solar-panel ridge setbacks when a home has an installed sprinkler system.

Community Development's building official reviews and approves plans for any builder-installed sprinkler system as part of the standard residential plan review and inspection process under the C3BC.