Contractor Deposit Law in California: The 10% or $1,000 Rule

Why ADU Deposits Go Wrong in California

When an ADU builder asks for a large check before lifting a hammer, that request tells you everything you need to know. The collapse of Anchored Tiny Homes made that brutally clear for California homeowners — and the warning signs were hiding in plain sight.

According to a KCRA investigation, the Contractors State License Board (CSLB) is still sorting through the fallout, in which hundreds of homeowners lost money. One victim, Renee Kumamoto, paid $168,000 upfront in exchange for a promised discount — and lost nearly all of it. CSLB has since identified similar issues with other ADU builders, pointing to a broader pattern of fraud in the industry.

An ADU is not a kitchen refresh. In Altadena, where garage conversions and backyard units routinely run into six figures, the sums at stake make homeowners attractive targets for builders who structure payments illegally. The pitch is always seductive: pay more now, save money overall.

But CSLB's Katherine White put it bluntly: "A lot of people gave too much money up front and they gave up too much money without the products being delivered." Her guidance is simple — once the contract is signed, payments should only cover supplies that have been delivered or work that has been completed.

The consequences of ignoring this are severe. Under California law, taking an illegal deposit violates license conditions, and CSLB can suspend or revoke the contractor's license entirely, as legal analysis of deposit disputes makes clear.

Before you sign anything with an ADU builder — whether found through a national franchise or a local referral — watch for these red flags:

• A deposit request above $1,000 or 10% of the contract price, whichever is less
• Pressure to pay the full project cost upfront "for a discount"
• Requests for cash, which White warns against because payments should be traceable
• No written, milestone-based payment schedule tied to work performed

Here in Altadena, where many homeowners are rebuilding after the Eaton Fire and weighing ADUs as housing solutions, vetting matters more than ever. At Altadena ADU Builder, we treat the deposit question as a first-pass filter: a builder like JMB Builders LLC (CSLB #1103479) operates within the legal payment framework — and any builder who won't deserves scrutiny. You can verify any California license yourself by calling 800-321-2752 or searching the CSLB website before signing.

The 10% or $1,000 Rule Explained

Imagine handing a contractor a $20,000 check before a single nail is driven — then watching the crew vanish. That scenario is exactly what California's deposit law exists to prevent, and it's a rule every Altadena homeowner planning an ADU should know cold.

The governing statute is Business & Professions Code Section 7159, enforced by the Contractors State License Board. Under it, a licensed contractor may only require a down payment of $1,000 or 10% of the contract price, whichever is less — excluding finance charges — on a home improvement job or swimming pool, as confirmed by CSLB's official consumer guidance. There are no exceptions for special-order materials, no matter what a salesperson tells you.

The math matters. On an $8,000 project, the maximum legal deposit is $800 — a contractor demanding $1,500 to $2,000 up front is breaking state law. On a typical ADU, which costs far more than $10,000, the cap is simply $1,000. A builder asking for 30% or 50% down is not being aggressive; they are violating the statute.

The deposit rule doesn't stand alone. Section 7159 bundles it with companion protections that shape the entire payment structure of your project:

• Contracts must include a detailed written payment schedule tied to project milestones.
• After the down payment, no payment may exceed the value of work performed and materials delivered.
• Any home improvement project over $500 requires a written contract — and a CSLB license for projects $500 or more.

CSLB's Katherine White puts the payment principle plainly: once you're in the contract, payments should only cover supplies that have been delivered or work that's been done, according to CSLB. The stakes are real — in the Anchored Tiny Homes collapse, one homeowner lost $168,000 after paying upfront for a discount, and CSLB has identified similar issues with other ADU builders.

Violations carry consequences on the contractor's side too. Taking an illegal deposit violates license conditions, and the CSLB can suspend or revoke the contractor's license. That makes the deposit question a simple vetting test: a compliant builder — like the licensed contractors we feature at Altadena ADU Builder, including JMB Builders LLC (CSLB #1103479) — will structure payments around milestones, not a large check on day one. If a builder's first ask exceeds the cap, walk away before signing anything.

Your Deposit as a Builder Vetting Tool

Here's a simple test that separates legitimate ADU builders from the ones who will cost you everything: look at the down payment they ask for. Under California Business & Professions Code Section 7159, a contractor can require a deposit of no more than $1,000 or 10% of the contract price, whichever is less — and there are no exceptions, not even for special-order materials, according to the Contractors State License Board.

That makes the deposit request a built-in compliance litmus test. If a builder asks for 30% or 50% down on your ADU project, that builder is breaking state law — full stop. On a typical ADU costing well over $10,000, the legal maximum deposit is $1,000. Anything more is a red flag you shouldn't ignore, no matter how persuasive the explanation.

The stakes are real. CSLB is investigating the collapse of Anchored Tiny Homes, where hundreds of homeowners lost money; one victim, Renee Kumamoto, lost $168,000 after paying upfront for a discount. The agency has identified similar issues with other ADU builders, making this pattern especially relevant for California homeowners planning backyard units.

Before you sign anything, verify the builder's license. You can call CSLB at 800-321-2752 or search its website to confirm the license is active and in good standing. CSLB licenses roughly 285,000 contractors across 45 classifications, so there's no excuse for skipping this step.

How you pay matters as much as how much. CSLB's Katherine White advises against cash — "You shouldn't be using cash" — because traceable payments create a paper record if a dispute arises. She also stresses that after the deposit, "the payments you should be giving to the contractor are only for supplies that have been delivered or work that's been done."

A compliant contract should include:

• A detailed, written payment schedule tied to project milestones
• Payments that never exceed the value of work performed (the deposit is the only exception)
• A deposit of no more than $1,000 or 10% of the contract price, whichever is less
• A licensed contractor with a verifiable CSLB license number

This is the structure you should expect from a licensed local builder. JMB Builders LLC (CSLB #1103479), an Altadena-based general contractor whose ADU and rebuild work is documented on jmb-builders.com, structures payments around milestones rather than large upfront sums — the kind of arrangement that keeps you protected under Section 7159. When we evaluate builders for the Altadena ADU Builder guide, this payment structure is one of the first things we check.

If a builder fails this test, walk away. Recovering an illegal deposit through CSLB complaints, small claims court, or arbitration is possible — but avoiding the problem before you sign is far easier than untangling it afterward.

What to Do If a Builder Takes Too Much

Discovering your builder took more than the legal deposit is frustrating — but California gives you a clear escalation path, and the first step costs nothing. Before anything else, confirm whether the contractor is even licensed: call the CSLB at 800-321-2752 or search the CSLB website. That single check shapes your entire strategy.

If the builder is unlicensed, your position is actually stronger than you might expect. Under Business & Professions Code Section 7031, an unlicensed contractor cannot sue you to recover payment, and you can recover 100% of everything you paid — even if some work was completed. A licensed contractor who took an illegal deposit, by contrast, risks suspension or revocation of their license, which gives you leverage.

From there, follow a practical escalation sequence:

• File a free CSLB complaint. Expect confirmation within 2–3 weeks and an investigation lasting 2–6 months.
• Send a written demand letter requesting your deposit back. Roughly 40% of demand letters get ignored, so don't stop here if you hear nothing.
• File in small claims court, where the limit is $12,500 and filing fees run $30–$100, plus $50–$100 for a process server.
• For disputes under $15,000, request free, binding arbitration through the CSLB instead of litigating.

There's also a negotiation tactic worth trying before you escalate. Offer to dismiss your CSLB complaint and skip the small claims filing if the contractor refunds the full deposit within seven days — and if they counter with a 70–80% refund paid immediately, that's often worth accepting. As one California attorney notes, homeowners worried about retaliation in the form of a mechanic's lien can generally relax: contractors who disappear don't come back to file liens; they move on to the next victim.

The stakes are real. In the collapse of Anchored Tiny Homes, hundreds of homeowners lost money, including one victim who lost $168,000 after paying upfront for a discount — and CSLB has identified similar issues with other ADU builders. For an ADU project in Altadena, where contracts routinely run well into six figures, the difference between a $1,000 legal deposit and a 30% down payment can be the difference between a recoverable mistake and a catastrophic loss.

This is why we emphasize license verification at Altadena ADU Builder. Any builder we feature — including JMB Builders LLC (CSLB #1103479), whose work is documented on jmb-builders.com — holds an active California license you can independently confirm. If you're weighing builder proposals and want a second opinion on deposit terms and payment schedules, our free ADU feasibility consultation includes a cost-quiz concept render so you know what your project should actually cost before you sign anything.

Protecting Your Altadena ADU Budget Before You Sign

The most dangerous moment in your ADU project isn't during construction — it's the moment you hand over a deposit to the wrong builder. California law gives you a simple, powerful tool to protect yourself before you sign anything, and most homeowners never use it.

Under Business & Professions Code Section 7159, a licensed contractor can only ask for a down payment of $1,000 or 10% of the contract price — whichever is less. There are no exceptions for special-order materials, no matter what a builder tells you. On an Altadena ADU costing well over $100,000, that means the legal maximum deposit is $1,000, full stop.

Treat this as your compliance litmus test. A builder who asks for $10,000 or $20,000 down isn't being aggressive — they're breaking state law, and the CSLB can suspend or revoke a license for it. Before you sign, work through this checklist:

• Cap your deposit at $1,000 — anything more is an illegal request, even for special-order materials.
• Insist on a milestone-based written payment schedule tied to delivered materials and completed work, since payments cannot legally exceed the value of work performed.
• Never prepay the full project cost in exchange for a discount — one California homeowner lost $168,000 doing exactly this in the Anchored Tiny Homes collapse.
• Verify the license through the CSLB website or by calling 800-321-2752 before signing anything.

That last point matters more than ever in the ADU market. The CSLB is currently investigating the Anchored Tiny Homes collapse, where hundreds of homeowners lost money, and the agency has identified similar issues with other ADU builders across California. CSLB's Katherine White puts it plainly: pay only for supplies that have been delivered or work that's been done — and avoid cash, because traceable payments protect you.

License verification is quick and free. When we vet builders for the Altadena ADU Builder guide, we check CSLB status first — which is how JMB Builders LLC (CSLB #1103479), the featured builder in our guide, documents its licensed, Altadena-based ADU and rebuild work. An unlicensed contractor carries a different risk entirely: under state law they can't even sue to collect payment, which tells you how the industry views that arrangement.

The safest first step costs nothing. A free ADU feasibility consultation with a cost-quiz concept render lets you understand your project's budget and scope — and vet the builder's license, payment terms, and communication style — before any money changes hands. A reputable local builder will welcome the deposit cap and a milestone payment schedule; a builder who resists them has answered your question for you.