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Santa Clara County, California: ADU Regulations

City or County:

Santa Clara County, California

Date Updated:



Allowable Urban Districts: R1/R1E/RHS/R1S/R3S/A1

Allowable Rural Zones: A/AR/HS/RR

Types of ADUs:

Attached, Detached and Junior ADU


Urban Districts: Single-story

Rural Districts: up to two-stories depending on lot size.

Lot Size:

Urban Districts:

On lots less than 10,000 sq. ft. only attached ADUs allowed. On lots larger than 10,000 sq. ft. either attached or detached permitted.

Rural Districts:

On lots .5 to less than one acre, only attached ADUs allowed. The min. lot size for detached is one acre.

Maximum ADU Floor Area:

Urban Attached:

Lots <20,000 sq.ft., 800 sq.ft. max;

Lots >20,000 sq.ft., 1,000 sq.ft. max

Urban Detached: 1,000 sq.ft. max

Rural Attached:

Lots <1 acre, 800 sq.ft. max

Lots 1-2.5 acres, 1,000 sq.ft.

Lots >2.5 acres, 1,200 sq.ft.

Rural Detached:

Lots <1 acre, 800 sq.ft. max.

Lots 1-2.5 acres, 1,000 sq.ft.

Lots >2.5 acres, 1,200 sq.ft.

Lot Coverage:

Must adhere to coverage limits of underlying zoning district.


2 bedrooms maximum.


No min/max


Require separate kitchen facilities.


ADUs require separate bathroom facilities.

Junior ADUs may include separate bathroom or may share bathroom with existing structure.

Note: Drainage and sewer connections should be assessed on a project by project basis.


One off-street parking space per unit required for secondary dwelling.

One additional space required for a secondary dwelling with more than one bedroom.

For applicable parking exemptions, see Section 4.10.340(FX3).


Must follow guidelines of underlying zoning district.

Setback of no more than five feet from side and rear property lines required for above existing garage units.

Note: Fire Department regulations should be assessed on a project by project basis.


May not exceed 21'


Urban ADUs may be no nearer than 6' to primary dwelling.

Rear Yard Coverage:

Must follow requirements established by zoning district in which lot is located.


Unless noted on Priority Lists No. 1 and 2, design standards are advisory. Certain features, materials or forms may be required by means of design review or ASA approval.

Note: Historic Neighborhoods or Districts should be assessed on a project by project basis.



Source Code:

Important Note: Rules and regulations are updated and changed frequently. It’s one of our jobs to be up to speed and navigate those regulations. Let us know if our website isn’t up to date or if you have any information that could help. Cheers!