ADU Cost & Rules in Los Angeles, CA

Planning an accessory dwelling unit in Los Angeles? Here are the current construction cost ranges, permit fees, and the zoning rules that apply to most residential lots — compiled from city and state requirements and 2026 regional cost data.

How much does an ADU cost in Los Angeles?

A detached new-build ADU in Los Angeles typically costs $180,000 – $400,000, while a garage conversion runs $80,000 – $180,000. Permit and city fees add $4,000 – $14,000, and most projects take 8–14 months from design to completion.

Do you need a permit to build an ADU in Los Angeles?

Yes. Every ADU in Los Angeles requires building permits, with typical city and permit fees of $4,000 – $14,000. Setback requirements are 4 ft side and rear, and owner occupancy is not required.

How big can an ADU be in Los Angeles?

ADUs in Los Angeles can be up to 1200 sq ft. No minimum lot size (state law). Local note: LADBS runs the largest pre-approved Standard Plan Program in the US (80+ designs), and its express plan check can cut review to 2–4 weeks. A 10% General Plan Maintenance Surcharge now applies to permit fees (June 2026). Coastal Zone lots (Venice, Pacific Palisades, San Pedro) need a costly Coastal Development Permit adding 2–4 months.

Cost breakdown for Los Angeles (2026)

Local note: LADBS runs the largest pre-approved Standard Plan Program in the US (80+ designs), and its express plan check can cut review to 2–4 weeks. A 10% General Plan Maintenance Surcharge now applies to permit fees (June 2026). Coastal Zone lots (Venice, Pacific Palisades, San Pedro) need a costly Coastal Development Permit adding 2–4 months.

Get an estimate for your project

Ranges above assume typical lots and standard finishes. For a number tailored to your size, type, and finish level, run the calculator:

Figures reflect published city fee schedules and 2026 regional construction data; rules change — confirm with the Los Angeles planning department before designing. Last reviewed 2026.