Orange County · Timeline

How long an ADU really takes in Orange County

Total elapsed schedule from the first site walk to the final inspection. Plan check is rarely the long pole — utility coordination and trade scheduling usually are.

Stage by stage

Survey + design: 3–5 — Standard suburban lots — minimal site work.
HOA architectural review: 4–8 — Skip if not in a master-planned community.
City plan check: 4–6 — Irvine / Anaheim portals are very fast.
Construction: 14–20 — Detached new-build.

Permit clock vs total schedule

Ministerial permit: 6–10 weeks
Discretionary review (when triggered): 16–28 weeks

What slips schedules in this area

Irvine, Anaheim, and Santa Ana run streamlined ADU portals — typically the fastest in OC.
Coastal cities (Newport, Laguna, Huntington) often need a Coastal Development Permit.
Master-planned community HOAs (Irvine Ranch, Coto, Talega) add architectural review on top of permits.

Reference

Terms and guides for this page

Glossary terms

Ministerial Review
Permit review based purely on objective standards — no public hearing, no discretion.
Coastal Development Permit (CDP)
Permit required for construction inside California's Coastal Zone, issued by the city or the California Coastal Commission.
Soils Report
Engineering study of subsurface soil conditions, required for hillside and certain ADU lots.
Setback
Minimum distance a structure must be from a property line.
AB 2221
2022 amendment that closed loopholes in AB 68 — clarified setbacks, height, and the 60-day clock.
ePlan
LADBS's fully electronic plan-check portal for residential and commercial permits.

Field guides

The Los Angeles ADU permit process, step by step
Permitting an ADU inside the City of Los Angeles takes about 8–11 weeks of plan check (LADBS) plus 2–4 weeks of pre-submittal prep. State law caps ministerial review at 60 days from a complete submittal. Total city + utility fees for a 700 sqft detached ADU typically run $13,000–$26,000.