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

Glendale Municipal Code Sec. " In practice this means the trigger runs one direction only, from the primary house to the accessory unit, keyed to whichever edition of the California Fire Code or California Residential Code applied when the main dwelling was built or last significant permitted. If that dwelling was constructed under a code cycle mandating sprinklers, either because of its size, unit count, or fire-flow conditions, the new ADU must carry sprinklers too, typically tied into the same water supply and monitored system.

If the primary dwelling predates any sprinkler mandate and was never required to install them, the ADU can be built without them even though it is new construction, a carve-out that departs from how sprinklers are normally handled for standalone new residential structures. Glendale's Building and Safety Division checks this history during ADU plan check by pulling the primary dwelling's permit records, and applicants should expect a records review rather than a blanket rule based on the ADU's own size or attachment status. Because the section frames the ADU program as ministerial and nondiscretionary, staff cannot impose sprinklers beyond what this cross-reference requires, and they cannot use the ADU application as an opportunity to force a retrofit on the existing house.