Accessory dwelling unit construction cost

Looking for accessory dwelling unit construction cost in San Bernardino, CA? Call AccessoryDwellingUnit Pros for a contact a provider — no obligation. Licensed adu builders serve San Bernardino 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

Building costs vary based on the size of the unit, the quality of finishes, the complexity of the site foundation, and utility connections. You should consider these expenses when budgeting for a long-term property investment or home expansion. Exact pricing confirmed free on the call.

Frequently asked in San Bernardino

What are the disadvantages of ADUs?

Potential disadvantages include increased property taxes and utility bills for the main home. You might also face neighborhood concerns about increased density or parking. Permitting and construction can also be time-consuming. A pro can help you understand these aspects for your San Bernardino property.

How much does an ADU cost in California?

The price of an ADU in California depends heavily on its size, design complexity, and the specific site. Factors like foundation work and utility connections in San Bernardino can significantly impact the total cost. Getting a personalized quote is essential for accurate budgeting.

What are the rules for ADUs in California?

California state law provides a framework for ADU development, but local San Bernardino city ordinances apply. These rules cover aspects like minimum lot size, setbacks, and parking requirements. A local specialist will be up-to-date on these regulations.

Is ADU allowed in Maryland?

This service is for California. Regulations for ADUs vary by state and even by county. If you are in Maryland, you would need to research their specific local zoning laws and building codes for ADU approval.

What are the rules for ADU in California?

California ADU laws generally allow for ADUs on most single-family residential lots. There are specific requirements for minimum unit size and limitations on imposing excessive parking demands. The San Bernardino planning department will have the detailed local rules.

Grant programs for ADUs in California have existed, but their availability and terms can change. It’s wise to inquire about current funding opportunities when you speak with a pro. They can offer the most current information for your San Bernardino project.

Also serving nearby: Rialto · Fontana · Jurupa Valley · Rancho Cucamonga · Riverside

All cities in California →

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

Service area details

223,728residents

3,602per sq mile

8ZIP codes served

Serving all of San Bernardino — population 223,728; about 3,602 residents per square mile across 62.1 sq mi. ZIP codes covered include 92401, 92402, 92403, 92404, 92405, 92406, 92407, 92408.

Neighborhoods served in San Bernardino: Muscoy, Delmann Heights, North San Bernardino, South San Bernardino, Loma Linda (nearby) — and every surrounding area.