Mendocino County, CA Building Safety: Fire Sprinkler Requirements (2026)

23 is Mendocino County's 1981-adopted performance-standard alternative to the full California Building Code for owner-built rural dwellings, created because the county's mountainous terrain and lack of developed roads make conventional code compliance difficult for many rural parcels. 345, added by Ord. No. 4404 in 2018, requires all new structures under this chapter to meet the Chapter 7A California Building Code exterior wildfire-exposure material rules, but expressly says residential fire sprinklers are not required in Limited Density Rural Dwellings. The county extended the same logic to accessory housing: under Sec.

030(A)(9) and (B)(8), adopted by Ord. No. 4538 in 2024, attached and detached ADUs are not required to carry sprinklers if the primary residence doesn't have them, and building an ADU cannot trigger a sprinkler retrofit of the existing house. 045(E) extends the identical exemption to ADUs built under the state's exemption-from-development-standards pathway, including units carved out of existing multifamily buildings. 23) remain subject to the state's separate sprinkler requirements for standard new one- and two-family construction, which this local exemption does not touch.