Cost in LA
What an ADU actually costs in Los Angeles — from soft costs and site work to finishes, contingency, and the line items most builders quietly omit.
- Starting price (turnkey)
- $250K 600–800 sq ft, flat lot
- Typical $/sq ft
- $425–$525 design-build, all-in
- Soft costs share
- 12–18% design, permits, fees
- Recommended contingency
- 8–10% of hard costs
Los Angeles ADU pricing is shaped by lot conditions, finish level, and the city's design and engineering requirements — not by square footage alone. A 600 sq ft detached unit in flat Mar Vista and a 600 sq ft unit on a Glendale hillside are not the same project. This hub breaks the real cost stack down line by line.
01.01The cost stack
Hard costs (foundation, framing, MEP, finishes) are 70–78% of total. Soft costs — architecture, structural, Title 24, surveys, geotech — run 12–18%. City fees (LADBS plan check, school fees, sewer capacity) typically add another 4–7%. Hold 8–10% contingency separate. If a builder's quote omits any of these buckets, the price is not the price.
01.02What moves the number
Site access, slope, soil class, and existing panel capacity move the number more than finishes. A 200-amp service upgrade is the single most common $8K–$15K surprise. Hillside parcels add geotech (~$4K) and grading. Coastal overlays add review time, not direct cost. Standard Plan ADUs save $6K–$12K in design fees and 30–60 days in permits.
01.03Where to spend, where not to
Spend on envelope, windows, and HVAC — they show up monthly on operating cost and tenant satisfaction. Don't overspend on appliances and tile in a rental unit; mid-grade outperforms premium on rent-per-dollar. For owner-occupied or family use, the calculus inverts.
From the desk
- 6 min
The honest line items most ADU quotes omit
Sewer capacity, Title 24 PV, panel upgrades, and the contingency conversation.
- 5 min
Why $/sq ft is a misleading metric in LA
Two identical floor plans, $80K apart — what actually drove the gap.
- 4 min
Standard Plan ADUs: when they save money, when they don't
The trade-off between speed and parcel-specific design.