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

207 adds Section 903 to the adopted 2025 California Fire Code. Fire area calculations include every floor, mezzanine and basement, plus any attached projection greater than four feet, and structures within six feet of each other, or connected by a breezeway or covered walkway, have their floor areas aggregated when deciding whether the 5,000-square-foot trigger is met. Buildings three stories or taller require sprinklers no matter their height, and any Group A occupancy is covered outright. 4, which normally lets a designer add fire walls instead of sprinklers, may not be used to avoid installing sprinklers in new construction or during a remodel or addition.

Condominium and apartment buildings up to four stories may instead use an NFPA 13R system with full attic protection, meaning quick-response sprinklers spaced through the attic, hydraulic calculations based on flowing at least four sprinklers, and listed steel piping (listed CPVC is allowed only under attic insulation with special application heads). Every system needs an interior warning device approved by the Fire Chief. Retrofits apply to existing buildings too: if a remodel or addition's value exceeds fifty percent of the current Stanislaus County assessed valuation of the building's improvements and the structure exceeds 5,000 square feet, or if the remodel itself pushes the building over that threshold, sprinklers must be installed. The section states it cannot be read to lower the protection already required under the California Building Code.