An ADU is a house. Detached units in Los Angeles run $150,000 to $400,000 or more, garage conversions typically $80,000 to $180,000, and both require a full permit set: architectural, structural, Title 24 energy compliance, and MEP. The builder needs an active B General Building licence, real experience with the LA ADU ordinance 186,481 and LAMC 12.22A.33, and a contract with a schedule of values you can actually track. Vet the permit path as carefully as the price, because on ADUs the plan check phase is where budgets and timelines quietly break.
Verify the Builder Before the Design Starts
Check cslb.ca.gov for an active **B General Building** licence, the $25,000 bond and a workers' compensation certificate. Ask for the general liability certificate from the insurer, at least $1,000,000 per occurrence and $2,000,000 aggregate, and ask whether they carry builder's risk on the structure during construction. Then ask for permit numbers from three completed ADUs in the City or County of LA so you can look them up. Ask who prepares the drawings: an in-house design team, an architect on contract, or a drafting service. Ask who signs the Title 24 energy compliance documentation. If a builder cannot name their structural engineer and their Title 24 consultant, they have not run many of these through plan check.
Pro Tip
Ask for permit numbers, not photos. Anyone can show photos; a permit record shows who actually built it.
Red Flags on ADU Proposals
A per-square-foot price with no scope behind it. No line for utilities, when a new detached unit may need a separate electrical subpanel, a sewer lateral connection, water service upsizing and gas, and those connections regularly run into five figures. No allowance structure for finishes, or allowances so low they guarantee change orders. No mention of Title 24, which every new conditioned structure in California must satisfy. Silence on hillside conditions when the property is subject to the Baseline Hillside Ordinance 184,802, or on a Coastal Development Permit if the parcel sits in the Coastal Zone. A deposit above $1,000 or 10% of the contract, whichever is less. And any promise of a specific permit turnaround in weeks, which nobody can guarantee.
Pro Tip
Utility connections are the most commonly under-budgeted ADU line. Ask for them itemised, not assumed.
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What a Real ADU Proposal Contains
Two phases, priced separately. Design and permitting: survey, architectural set, structural engineering, Title 24 compliance, plan check submittal and corrections, and city fees held as a pass-through with receipts. Construction: a schedule of values by trade, typically site work and utilities, foundation, framing, roofing, windows and doors, MEP rough, insulation, drywall, exterior finish, interior finishes, cabinetry, flooring, fixtures, and final grading. Allowances stated per item with unit prices, not lump sums. A construction duration range in months, with the caveat that inspection scheduling is outside anyone's control. Payment tied to completed and inspected milestones. Garage conversions land at $80,000-$180,000 because the shell exists; new detached construction at $150,000-$400,000 because it does not.
Pro Tip
Ask that city fees be paid at cost with receipts attached, rather than marked up inside a lump sum.
Questions and Contract Terms
Who holds the permit, and is it in your licence. What happens to my price if plan check requires structural changes. Which allowances are most likely to be exceeded, and by how much on your last three jobs. Are your framing, MEP and finish crews employees or subs, and will I get conditional lien waivers with every payment. What is your change order process, and does work stop until I sign. What is the workmanship warranty, and how does it sit alongside the ten-year statutory limit for latent construction defects in California. Who is my point of contact and how often do I get a written update with photographs. Confirm the contract carries everything California requires: licence number, start and completion dates, payment schedule, three-day right to cancel and the mechanics lien warning.
Pro Tip
Keep a final retention of five to ten percent until punch list completion and final sign-off.
Final Thoughts
ADUs reward homeowners who vet the permit path, not just the price. Verify the B licence, insurance and real LA permit history, split design and construction into separately priced phases, itemise utilities, and pay against inspected milestones. RYV designs, permits and builds ADUs and additions across Los Angeles with our own crews, and we price the permit phase honestly because that is where most ADU budgets fail.
Frequently Asked Questions
An active B General Building licence, since an ADU spans framing, roofing, MEP and finishes. Verify status, the $25,000 bond and workers' compensation at cslb.ca.gov, then ask for a general liability certificate direct from the insurer and confirm whether builder's risk coverage is carried during construction.
New detached ADUs generally run $150,000 to $400,000 or more depending on size, site access and finish level. Garage conversions typically land between $80,000 and $180,000 because the shell and slab already exist. Utility connections and site work are the two lines most often underestimated.
A site plan and architectural drawings, structural calculations and details, Title 24 energy compliance documentation, and mechanical, electrical and plumbing information. Los Angeles ADUs are governed by ordinance 186,481 and LAMC 12.22A.33, with additional requirements on hillside parcels and inside the Coastal Zone.
Design and permitting priced as its own phase, then construction paid against a schedule of values tied to completed and inspected milestones. The initial deposit is capped by law at $1,000 or 10% of the contract, whichever is less. Hold a five to ten percent retention until the punch list is finished.
