What is the maximum ADU deposit in California?

$1,000 or 10 percent of the contract price, whichever is less.

Does the cap apply outside California?

No. Other states have their own rules.

California requires approximate start and completion dates in a home improvement contract.

Present = items marked Yes. Deposit cap = the lesser of $1,000 or 10% × contract price (California Bus. & Prof. Code § 7159.5).

Inputs on this tool, in the order they appear on the form.
Input	What it is actually asking
Progress payments	California requires each one stated in dollars and tied to the work it pays for (§ 7159).
Change orders	Written and signed before the work (§ 7159).
Deposit	The first payment before work starts.

Including one where the naive answer misleads, which is the example most calculators leave out.

Type the price and a deposit above the cap. The tool says so; ask the builder to restructure.

Mark exclusions No. Ask what is not included before you sign.

Each missing item is a question to ask, not a verdict on the builder.

Do not treat a full score as legal approval. See the ADU contract checklist and consider legal review.

What is the maximum ADU deposit in California?: $1,000 or 10 percent of the contract price, whichever is less.
Does the cap apply outside California?: No. Other states have their own rules.
What if the contract has no dates?: California requires approximate start and completion dates in a home improvement contract.
Is this legal advice?: No. It is a checklist.

Figures dated 27 October 2026. Last reviewed September 16, 2026.