How Much Does an ADU Cost in Los Angeles?

Average ADU costs in Los Angeles (2026)

ADU construction in Los Angeles typically ranges from $150,000 to $450,000 depending on size, finishes, and site conditions. A garage conversion is the most affordable path, averaging $90,000–$180,000, while a new-build detached 1,200 sq ft ADU runs $350,000–$500,000.

Prefab ADUs split the difference, with turnkey installations ranging from $180,000 to $320,000 including foundation, utility hookups, and permits.

What drives the price

Three factors move the needle most: square footage, site conditions (sloped lots, utility distance, tree removal), and finish level. Title 24 energy compliance and the mandatory solar tie-in for new construction also add cost.

Permit and city fees in LA typically run $8,000–$18,000 depending on jurisdiction and impact fees.

How to budget

Add a 10–15% contingency for change orders and unforeseen utility upgrades. Talk to a licensed ADU builder early to lock in a fixed-price design-build contract before drawings are finalized.