Last updated: September 24, 2026
What affects the price
Building an ADU involves several moving parts that shape your total investment. The final figure depends heavily on whether you choose a prefab unit or a custom build from the ground up. Site conditions are another major factor; if your property requires extensive grading, utility trenching, or foundation work, costs will climb. You also have to consider your choice of finishes, like high-end appliances or custom cabinetry. Navigating local permit fees and impact assessments also adds to the total.
About this service
A contractor oversees the physical build, managing the subcontractors, materials, and daily construction progress. They are responsible for making sure the structure is built according to the approved plans and local safety standards. You need a contractor when you have your designs finalized and are ready for the actual building phase to begin. They act as the primary point of contact for all site activity.
Frequently asked in Santa Clara
What are the benefits of a prefabricated accessory dwelling unit in Santa Clara?
Are there specific ADU companies that operate in Santa Clara?
How much does an accessory dwelling unit cost in Santa Clara?
What are the rules for accessory dwelling units in California, and how do they apply to Santa Clara?
Are there financing options for accessory dwelling units in Santa Clara?
What does 'affordable ADU' mean in Santa Clara?
What is the cost to build an accessory dwelling unit in Santa Clara?
Also serving nearby: Sunnyvale · Burbank · Fremont · San Jose · Hayward
More on this: HUD ADU resources — ADU policy and financing research.
Service area details
Serving all of Santa Clara — population 131,062; about 7,170 residents per square mile across 18.3 sq mi. ZIP codes covered include 95050, 95051, 95052, 95053, 95054, 95055, 95056.
Neighborhoods served in Santa Clara: Old Quad, Rivermark, Agnew, Franklin Square, Westfield — and every surrounding area.
Areas we serve
Browse by state, then city.
