Accessory dwelling units adus — San Mateo, CA
Last updated: September 24, 2026
What affects the price
Building an ADU involves several moving parts that shape your total budget. The biggest factor is whether you choose a prefabricated unit or a custom build on-site. Site preparation is also significant; if your land requires extensive grading, utility trenching, or foundation work, costs will climb. Your choice of finishes—like kitchen cabinetry, flooring, and siding materials—also shifts the bottom line. We help you navigate these variables to find a setup that fits your property. Exact pricing confirmed free on the call.
About this service
Accessory dwelling units, or ADUs, are secondary housing units on a single-family lot. They provide flexible living arrangements for families, renters, or home offices. As housing needs evolve, more people are turning to ADUs to maximize their land use and increase property utility. Exact pricing confirmed free on the call.
Frequently asked in San Mateo
What's the accessory dwelling unit cost in San Mateo?
How do I get an accessory dwelling unit permit in San Mateo?
What makes the best ADU in San Mateo?
What are the requirements for ADU construction in San Mateo?
Are prefab ADUs a good fit for San Mateo properties?
What's the accessory dwelling unit contractor situation in San Mateo?
Are there accessory dwelling unit grants in San Mateo?
Also serving nearby: Hayward · Daly City · Oakland · Sunnyvale · Fremont
More on this: HUD ADU resources — ADU policy and financing research.
Service area details
Serving all of San Mateo — population 101,327; about 8,350 residents per square mile across 12.1 sq mi. ZIP codes covered include 94401, 94402, 94403, 94404, 94497.
Neighborhoods served in San Mateo: Downtown San Mateo, Bay Meadows, Shoreview, San Mateo Village, Edgewater Isle — and every surrounding area.
Areas we serve
Browse by state, then city.
California (4)
All of California · Rialto · San Buenaventura (Ventura) · San Mateo · Vacaville