San Mateo County
Foster City ADU rules
Foster City has an official local rule record in this scrape. Provider research is grouped at the San Mateo County level.
Local rule facts
Min/max ADU size
Min:150 square feet Max ADU in single-family zoning districts: 1200 square feet or 50% of main home floor area (whichever is less), unless under 800 square feet (state law allows an ADU up to 800 square feet on every property, some exceptions may apply) Max ADU in...
Height
JADU – Within existing structure Attached ADU: Shall not exceed 25 feet in height, or the height of the primary dwelling, whichever is lower. ADUs shall not exceed two stories in height. Detached ADU: 16 feet, except within ½ mile of major transit stop or high-quality...
Setbacks
Side and Rear: 4 feet Front: may not be located in the front yard.
Parking
JADUs: No parking required ADUs: One spot may be required (tandem allowed). No parking required if: The ADU is located within one-half mile walking distance of public transit. The ADU is a conversion ADU. When there is an approved car share vehicle for which a Foster...
Owner occupancy
JADU: Required, ADU: not required for ADUs built recently (2020-2024)
Process
-at-a-Glance FAQs Floorplans Inspiration Glossary Guidebook + Exercises Pre-Designed Plans Process-at-a-Glance See the resources page Events About Contact Getting Started Learning the Rules Budgeting Design Permitting Construction Renting Getting Started Learning the...