California ADU Laws in 2026: What Homeowners Can Actually Build

State law keeps opening doors for accessory dwelling units. Here is what the 2026 rules mean for your lot, your permits, and your property value.

California's ADU statutes — AB 68, AB 881, SB 9, and the rounds of updates since — have made accessory dwelling units a right, not a favor. In 2026, nearly every single-family lot in our service area can add at least one ADU, often two units with a JADU.

The Numbers That Matter

Statewide floor: an 800 sq ft, 16-foot-tall ADU with 4-foot rear and side setbacks must be approved ministerially — no discretionary hearings. Larger units up to 1,200 sq ft are common depending on the city. Detached, attached, and garage conversions all qualify.

Permits in 60 Days — By Law

Cities must approve or deny a complete ADU application within 60 days. In practice, Bay Area building departments run 8-16 weeks with plan-check corrections, which is why complete, code-clean drawings matter more than ever.

Utility and Title 24 Realities

Budget for sewer lateral capacity checks, electrical panel loads, and Title 24 energy compliance — solar is required on new detached ADUs. These are the line items that turn cheap internet estimates into change orders when your contractor hasn't built ADUs before.

JMG Construction Services manages ADU feasibility, design, permitting, and construction under one license — #1007864. Tell us your city and we will tell you exactly what your lot allows.