Cost to build accessory dwelling unit

Looking for cost to build accessory dwelling unit in Los Angeles, CA? Call AccessoryDwellingUnit Pros for a contact a provider — no obligation. Licensed adu builders serve Los Angeles and the surrounding area, and you'll get straight answers on timing and what affects the price.

Last updated: September 24, 2026

What affects the price

Building an ADU is a custom project, so costs vary based on your specific choices. Site conditions are the biggest factor; if your land requires significant grading, utility extensions, or foundation work, those expenses add up quickly. Choosing high-end finishes, custom cabinetry, or complex roof lines will also push the budget higher compared to a standard design. Prefabricated units often offer predictable costs, while custom site-built structures allow for more flexibility but can be harder to estimate upfront. Exact pricing confirmed free on the call.

About this service

Determining the cost requires looking at site preparation, foundation work, and the level of interior finishing you choose. Costs change based on whether you opt for a pre-designed layout or custom architecture. You should research these costs when you are ready to evaluate the financial return of your property upgrade. Exact pricing confirmed free on the call.

Frequently asked in Los Angeles

What are the disadvantages of ADUs in Los Angeles?

How much does an ADU cost in Los Angeles?

What are the rules for ADUs in California?

Is an ADU allowed in my backyard in Inglewood?

While there have been grant programs in California aimed at encouraging ADU development, specific funding availability can change. These grants often have income and project requirements. It's best to discuss current incentives with the pros. They can inform you about any applicable programs.

What are the benefits of an ADU in Santa Monica?

In Santa Monica, an ADU can provide a valuable source of rental income or multi-generational housing, helping to address housing needs. It's a way to increase your property's value and potentially offset the high cost of living near the coast. The pros can guide you through building a compliant and profitable ADU.

Also serving nearby: Santa Monica · Inglewood · South Gate · Compton · Torrance

All cities in California →

More on this: HUD ADU resources — ADU policy and financing research.

Service area details

3,820,914residents

8,120per sq mile

8ZIP codes served

Serving all of Los Angeles — population 3,820,914; about 8,120 residents per square mile across 470.5 sq mi. ZIP codes covered include 90001, 90002, 90003, 90004, 90005, 90006, 90007, 90008.

Neighborhoods served in Los Angeles: Hollywood, Downtown LA, Westwood, Pasadena, Long Beach, Koreatown — and every surrounding area.