How to Hire an ADU Builder in California (2026)
California ADU law (AB 68, AB 1033, SB 9) created a $300-450K build opportunity and a predator class of 'ADU specialists' who take deposits and vanish. These seven steps identify a real ADU builder and avoid the three scam patterns documented by CSLB in 2024-2026.
Step 1: Check CSLB license class B + ADU project history in the last 2 years
ADUs require license class B. Beyond active status, ask for three completed ADU addresses in the last 2 years — preferably in LA County. Drive by two of them. If the builder can't provide recent ADU completions, they are learning on your project.
Step 2: Decide pre-fab/modular vs site-built before getting bids
Pre-fab (e.g., Villa Homes, Abodu, Samara) is 4-6 months faster but 10-15% more expensive per sqft and restricted to lots with good crane access. Site-built gives you full custom control and better integration with the primary dwelling but takes 8-14 months. Pick one before bidding — bidders scoping both give muddy numbers.
Step 3: Apply for LADBS Standard Plan Program if the ADU is under 1,200 sqft
LADBS maintains a library of pre-approved ADU plans (the Standard Plan Program) that cut plan-check from 8-12 weeks to 2-4 weeks. If the lot is flat, outside HPOZ, outside coastal zone, and outside hillside ordinance — and the ADU is under 1,200 sqft — the Standard Plan Program is the fastest path. The builder should have a Standard Plan portfolio to show you.
Step 4: Get a utility-capacity letter from LADWP before signing
Electrical service upgrades (100A → 200A) are a $8-15K line item that doesn't show up until LADBS plan-check flags it. Call LADWP ADU hotline (213-367-2787) before signing any contract and confirm the existing service can handle the new load, OR confirm the upgrade cost is explicit in the contract — not a future change order.
Step 5: Verify sewer capacity at the lot
Older LA neighborhoods (pre-1960 construction) often have 4-inch sewer laterals that can't handle a second dwelling. A sewer-lateral upgrade is a $10-25K trench job that most ADU budgets omit. Ask the builder to confirm sewer capacity in writing with a scope reference, or exclude it and allocate the contingency.
Step 6: Cap the deposit at 10%, lock progress payments to permit + framing + MEP + final
ADUs have four natural inspection gates: permit issued, framing inspection passed, MEP (mechanical/electrical/plumbing) inspection passed, final inspection passed. Structure progress payments against those gates. A 30%+ deposit is an early warning signal — every 2024 Southern-California ADU scam CSLB documented started with a 30-50% deposit.
Step 7: Confirm the builder handles CalHFA ADU Grant paperwork if you're eligible
CalHFA ADU Grant provides up to $40K toward pre-development costs (design, permits, site prep) for income-eligible homeowners. If eligible, confirm the builder handles the application paperwork or names a cost consultant who does. See /guides/adu-financing-calhfa-grant-40k for details.
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