CaliCustomADU

ADU Builders in San Francisco, California

Whether you want a rental unit, a home for aging parents or a studio for adult kids, building an ADU in San Francisco has never been easier under California's ADU laws. Our team plans every project around the cool microclimates, fog belts and seismic activity typical of San Francisco.

Typical cost

$258k–$536k

Permit time

8–14 weeks

Est. rent

$2,700+/mo

Population

808,000

Free San Francisco ADU estimate

Popular ADU types in San Francisco

Our most requested projects in San Francisco are two-story ADUs over garages and detached backyard cottages. Many San Francisco parcels built between the 1950s and 1980s have wide rear yards that fit an 800–1,200 sq ft detached unit without touching the main house.

Design-wise, San Francisco homeowners in the Bay Area tend to favor compact, light-filled modern designs that maximize small urban lots.

Building an ADU in San Francisco County

Every San Francisco ADU we build is engineered around local conditions — especially seismic engineering, sewer lateral rules and high labor costs. We prepare complete plan sets so the city can approve within the state's 60-day review window, typically 8–14 weeks here.

At $2,700–$4,350 per month in rent, a new ADU in San Francisco can pay for itself in roughly 9.4 years.

San Francisco ADU FAQs

How much does it cost to build an ADU in San Francisco?

Most San Francisco ADUs we build land between $258k and $536k, depending on size, site work and finishes. Garage conversions sit at the low end; custom two-story units at the high end.

How long does ADU permitting take in San Francisco?

State law requires cities to act on complete ADU applications within 60 days. In practice, San Francisco permits typically take 8–14 weeks when plans are submitted complete — which is what our in-house drafting team focuses on.

What can I rent an ADU for in San Francisco?

Based on Bay Area rental trends, a new 1-bedroom ADU in San Francisco commonly rents for $2,700–$4,350 per month, putting typical payback around 9.4 years.

What are the biggest challenges for ADUs in San Francisco?

In San Francisco and the wider Bay Area, the issues we plan around most are seismic engineering, sewer lateral rules and high labor costs. We review these during a free feasibility check before you commit.

Is two-story ADUs over garages a good option in San Francisco?

Yes — two-story ADUs over garages are among the most popular projects we build in San Francisco. Newer subdivisions in San Francisco often have tighter side yards, so we frequently recommend attached ADUs or converting an existing garage to keep costs down.

ADU builders near San Francisco

Get a free ADU feasibility check in San Francisco

Tell us about your lot. We'll review zoning, setbacks and utilities and send a ballpark budget — no obligation.