Current 2026 cost ranges for every ADU type we build in California. Every project is fixed-price at contract signing — the number you sign is the number you pay.
We do not price by square foot alone and we do not give "ballpark" ranges that move after contract. Every project is scoped, engineered, and estimated in detail during the feasibility and design phases, and the resulting fixed price covers the full scope listed in the contract.
The prices shown below are honest, current California market ranges for 2026, based on the actual cost of the last 400+ ADUs we have built. Your final number depends on your lot, your jurisdiction, your finish level, and the site conditions we find during feasibility.
Permit and utility fees are paid directly by you at the jurisdiction's published rate. We do not add a markup to those fees and we do not bury them inside our construction price.
Construction cost only. Permit fees, utility connection fees, and jurisdiction-specific charges are separate and paid at cost.
| ADU Type | Size Range | Typical Construction Cost | Cost per Sq Ft | Details |
|---|---|---|---|---|
| Detached ADU | 500 – 1,200 sq ft | $245,000 – $420,000 | $400 – $480 | View |
| Attached ADU | 400 – 900 sq ft | $180,000 – $325,000 | $360 – $430 | View |
| Garage Conversion | 300 – 500 sq ft | $120,000 – $195,000 | $340 – $420 | View |
| Above Garage ADU | 500 – 900 sq ft | $235,000 – $395,000 | $420 – $490 | View |
| Junior ADU (JADU) | 150 – 500 sq ft | $65,000 – $145,000 | $320 – $400 | View |
| Commercial ADU | 400 – 1,500 sq ft | $210,000 – $520,000 | $420 – $550 | View |
All three packages use the same licensed crew, same structural standards, and same warranty. The difference is materials and finish detail.
We spell this out in the contract before you sign so there are no disputes later.
You only pay for work already completed. There is no large deposit at signing and no payment for future phases.
Slope, soil type, existing foundations, and required retaining walls can add 5–15% to a project. We assess these in feasibility before quoting.
Permit fees, impact fees, and review timelines vary widely. Some cities charge 3–4× the fees of neighboring jurisdictions for the same unit.
The further the ADU sits from your main electrical panel, gas meter, and sewer line, the more trenching and connection work is required.
Essential, Signature, and Custom packages span a real $120–150 per square foot range depending on materials, appliances, and detailing.
Title 24 compliance, all-electric ordinances, and solar-ready requirements in some jurisdictions add cost — but also long-term savings.
Material prices fluctuate. Your fixed price is locked at contract signing and honored through the entire construction phase regardless of market movement.
It is fixed at contract signing for the scope described in the contract. If you request additional scope — a larger deck, upgraded appliances, added cabinetry — that becomes a written change order before the work is performed. If site conditions reveal something that was not visible during feasibility (buried oil tank, unknown utility conflict), we document it with photos and a fixed change-order price before proceeding.
No. Our contract begins with a 5% payment that covers initial design and engineering work. That is not a deposit — it pays for work that starts the day you sign. The remaining 95% is paid in five milestone-based installments as the project progresses.
Three main reasons: labor costs, regulatory requirements (Title 24 energy code, seismic standards, fire separation), and permit/impact fees. California construction wages are among the highest in the country, and the state's energy and structural codes add real cost to every build. However, California also has the most permissive ADU laws in the country, which offsets some of the regulatory burden.
It depends heavily on location and unit size. In the Bay Area, a well-built 1-bedroom detached ADU currently rents for $2,800–$4,200 per month. In the Los Angeles metro, $2,200–$3,500. In San Diego, $2,000–$3,200. Many of our clients see the ADU pay for itself in 8–14 years from rental income alone, before accounting for property value appreciation.
Yes. Send us the address and your desired ADU type through the form below and we will respond with a rough cost range based on comparable projects in your area. It is a range, not a quote, but it is grounded in real numbers from our recent builds — not a number pulled out of thin air.
We do not lend directly, but we work with several California lenders that specialize in ADU construction loans and can connect you with them. See our Financing page for details on the options most of our clients use.
If the overage is due to a feasibility or design oversight on our side, we absorb it. If the overage is caused by a latent site condition that was not reasonably discoverable — an unmarked utility line, buried debris, or soil contamination — we present documentation and a written change-order price before proceeding, and you can pause or cancel the project if you prefer not to continue.
We work with California lenders that specialize in ADU construction loans, HELOCs, and cash-out refinancing. Most approvals take 2–4 weeks, and construction can begin immediately after closing.
Tell us the property and the type of unit you are considering. We will come back with a real cost range and, if you want to move forward, a fixed-price contract within two weeks.