Modular accessory dwelling unit

Looking for modular accessory dwelling unit in San Francisco, CA? Call AccessoryDwellingUnit Experts for a contact a provider — no obligation. Licensed adu builders serve San Francisco 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 major project, and the final bill depends on a few key things. Site prep is a big factor; if your land is sloped or needs extensive utility connections, costs go up. The materials you choose—from siding to kitchen finishes—also change the math significantly. Whether you’re building a detached unit or converting an existing garage shifts the permit requirements and structural work needed. We provide exact pricing confirmed free on the call.

About this service

These units are built in a factory setting and then transported to your property for final assembly. This option is often chosen to reduce construction time and minimize disruption to your neighborhood. The final price is influenced by transport logistics, site preparation, and the level of customization. Exact pricing confirmed free on the call.

Frequently asked in San Francisco

How do I get an estimate for an ADU in San Francisco?

To get an estimate for an ADU in San Francisco, start by calling us. We'll schedule a time to assess your property. This assessment helps us understand the scope of your project. We then provide a detailed quote. This quote covers design, permitting, and construction costs.

Who are the builders for ADUs in San Francisco?

Can I get a 24-hour ADU service?

While a 24-hour ADU installation isn't feasible due to permitting and construction times, we prioritize efficiency. Our process is designed to be as streamlined as possible. We work with pros who aim for timely completion. We can discuss realistic timelines for your San Francisco project.

What services are included in ADU projects?

What is ADU housing?

ADU housing refers to the accessory dwelling unit itself – a secondary, independent living unit on a single-family residential lot. It can be attached or detached. ADUs provide flexible housing options for families or renters. They are a practical way to add density and housing stock.

What are the steps for ADU construction?

What's the cost of building an ADU in San Francisco?

The cost of building an ADU in San Francisco varies based on size, design, and materials. Site conditions and utility connections also impact the price. We provide a detailed quote after a property assessment. This ensures you get an accurate estimate for your specific project.

Also serving nearby: Daly City · Richmond · San Mateo · Berkeley · Oakland

All cities in California →

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

Service area details

808,988residents

17,323per sq mile

8ZIP codes served

Serving all of San Francisco — population 808,988; about 17,323 residents per square mile across 46.7 sq mi. ZIP codes covered include 94102, 94103, 94104, 94105, 94107, 94108, 94109, 94110.

Neighborhoods served in San Francisco: The Richmond District, The Sunset District, Noe Valley, The Castro, North Beach, Daly City — and every surrounding area.