Mariposa County, CA Fire Regulations: Smoke Detectors (2026)

Mariposa County is unincorporated and does not have a separate city smoke-alarm code, so residents are governed by California's statewide requirements. Under Health & Safety Code section 13113.7, smoke alarms must be installed in dwelling units, and current rules require them in each bedroom (sleeping room), outside each separate sleeping area in the immediate vicinity, and on every story of the dwelling, including basements. Alarms must be approved and listed by the State Fire Marshal and installed per the manufacturer's and State Fire Marshal's instructions. In new construction and certain alterations, alarms must be hardwired with battery backup and interconnected so that when one sounds, all sound. For rentals, the owner/landlord must ensure smoke alarms are operable at the start of a tenancy, and as of 2014 landlords cannot shift testing and maintenance duties to tenants even in single-family rentals; tenants must notify the owner of any inoperable alarm. Separately, under Health & Safety Code section 17926, carbon monoxide alarms are required in most dwelling units that have a fuel-burning appliance, fireplace, or an attached garage. Because Mariposa County is a high-wildfire foothill and mountain area where many homes use wood stoves, propane, and generators, working smoke and carbon-monoxide alarms are an important baseline safety measure even though the rules are set at the state level rather than by county ordinance.