How much does an ADU cost in Los Angeles?
Our detached ADUs run from roughly $185,000 to $420,000. Here is what sets the price and which fees apply.
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How much does an ADU cost in Los Angeles?
Our detached ADUs run from roughly $185,000 for a 400–500 sq ft studio to $420,000 for a 900–1,200 sq ft two-bedroom. These are Siboni Development & Design's own ranges from recent detached projects in Los Angeles County, not a market average. A fixed price follows the free site assessment.
| Type | Size | Typical investment | Construction |
|---|---|---|---|
| Studio | 400–500 sq ft | $185,000 – $240,000 | 12–16 weeks |
| One bedroom | 600–750 sq ft | $260,000 – $330,000 | 16–20 weeks |
| Two bedroom | 900–1,200 sq ft | $340,000 – $420,000 | 20–26 weeks |
What makes the price go up or down?
Four things move the price: the size of the unit and its number of bedrooms, the site conditions, the distance to the sewer, water and electrical connections, and the finish level. A main panel upgrade or a long utility trench adds cost; a lot where the connections are close lowers it.
Does the city charge fees on top?
Permit and plan check fees apply to every ADU. Impact fees are different: state law exempts ADUs of 750 square feet of interior livable space or less. Above 750 square feet, impact fees must be charged in proportion to the size of the ADU relative to the main house.
| ADU size | Impact fees | Source |
|---|---|---|
| 750 sq ft or less | Exempt | Gov. Code § 66311.5 |
| More than 750 sq ft | Proportional to the size of the ADU relative to the main house | Gov. Code § 66311.5 |
What does our fixed price include?
The fixed price covers design, permits, utilities, finishes and landscaping. Every ADU we build has its own connections and, where it makes sense, its own meter: we trench and connect to the existing sewer lateral, upsize the main panel if needed, and pre-wire for solar and EV.
How do homeowners pay for an ADU?
Yes. Most of our clients use a HELOC, a cash-out refinance or a construction-to-permanent loan. We work with two local lenders who understand ADU appraisals and can walk you through the options before design starts.
Sources
- California Government Code § 66311.5
- California Department of Housing and Community Development, Accessory Dwelling Unit Handbook (March 2026)
Sources checked on . General information, not legal or financial advice. Rules change and each city applies its own standards: we confirm what applies to your lot during the free site assessment.
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