ADU Resources
Supporting you throughout your ADU journey
key resources for your adu project
Looking for advice?
If your community is a member of the San Mateo County ADU Resource Center, you can contact our staff for advice on your project. Check the Contact page for more details.
ADU Guidebook
A step-by-step guide to building an ADU in San Mateo County
Process At-A-Glance
A two-page overview of the entire ADU process.
ADU Calculator
Estimate potential costs, fees, and rents, and see how choices can impact your budget.
Pre-Designed Plans
ADU plans you can use or purchase, and some that are locally pre-approved.
Local ADU rules
An overview of ADU rules in your location.
ADU Stories
Spotlights on real ADUs built by homeowners in San Mateo County and across California.
