ADU Guide: Building an Accessory Dwelling Unit in Santa Clarita

State law vs local rules

California Government Code 65852.2 (the state ADU law) sets a floor: every single family lot can have at least one ADU plus one Junior ADU. Cities can add layers on top but cannot block ADUs entirely. Santa Clarita has its own ordinance that further shapes setbacks, height, and lot coverage.

Site feasibility

Before design, walk the lot for setbacks, sewer capacity, electrical service capacity, slope, and easement constraints. Detached new build ADUs need a footprint and yard space. Garage conversions reuse an existing structure. Junior ADUs sit inside the main house. Each path has its own cost basis and construction timeline.

Permits in {city}

ADU submittals are ministerial in California, meaning the city reviews them administratively without discretionary review. City of Santa Clarita Building and Safety. Permit Center via santaclarita.gov. SCMC Title 17. Note: unincorporated portions (Stevenson Ranch, Castaic) fall under LA County DPW. typically completes plan check in 60 to 120 days. SCMC Chapter 17.57 residential development standards. ADUs up to 1,200 sf, 16 ft tall (unless within an existing structure). Garage conversions usually clear faster than detached new builds.

Construction window

Site clearance, foundation, framing, MEP rough, exterior dry in, interior finish, fixture install, final inspection. ADU builds in Santa Clarita typically run 4 to 7 months of construction. From signed design contract to final inspection most projects total 8 to 14 months.