Sunnyvale, CA Building Safety: Fire Sprinkler Requirements (2026)

Section 16.17.080 locally amends 2025 California Residential Code Sections R309.1, R309.1.1, and R309.2 for the city of Sunnyvale. R309.1 requires an automatic residential fire sprinkler system in every townhouse unit, and extends the mandate to existing townhouse units whenever an addition or a conversion from non-habitable to habitable space exceeds 50 percent of the habitable building area. A narrow exception excuses a one-time addition to an existing townhouse that does not exceed 500 square feet of building area. Firewalls separating townhouse building areas must be built to the 2025 California Building Code without any openings or penetrations. Section R309.1.1 requires that sprinkler systems for townhouse units be designed and installed to NFPA 13D and local standards.

R309.2 imposes the parallel mandate on one- and two-family dwellings: new construction needs an automatic residential fire sprinkler system, and existing homes need one added when an addition or non-habitable-to-habitable conversion exceeds 50 percent of the habitable building area. An exception covers a detached accessory dwelling unit, but only if the existing primary residence lacks sprinklers, the detached ADU does not exceed 1,200 square feet, and the unit sits on the same lot as the primary residence. Design and installation again must follow NFPA 13D and local standards. The city also deleted 2025 California Residential Code Section R309.3 in its entirety, replacing whatever alternative or narrower provision that section would otherwise have supplied for the city with its own R309.1 and R309.2 mandates.