On single-family residential lots in unincorporated Santa Clara County, you can build one ADU (attached or detached) and one JADU. Your lot must be a legal lot of record with an existing or proposed single-family residence in a residential or mixed-use zone.

Under SB 1211, multifamily properties in Santa Clara County can build up to eight detached ADUs, as long as the number doesn't exceed existing units. Conversion ADUs from non-livable spaces are also permitted.

Yes, Santa Clara County allows Junior ADUs up to 500 square feet. A JADU must be contained entirely within the single-family residence with a separate entrance. JADUs must have an efficient kitchen but may share a bathroom with the primary dwelling. Owner-occupancy requirements apply.

Santa Clara County does not have a separate guest quarters classification that exempts structures from ADU rules. Secondary living spaces with kitchens are classified as ADUs.

Detached ADUs in Santa Clara County can be up to 1,200 square feet. Provisions vary for rural vs. urban unincorporated districts and by lot size. ADUs up to 800 square feet with 4-foot setbacks qualify for streamlined approval.

Attached ADUs are permitted up to 1,200 square feet or 50% of the primary dwelling's floor area, depending on local provisions. State law guarantees at least 850-1,000 square feet for attached ADUs.

Yes. Under California state law, ADUs up to 800 square feet with 4-foot setbacks and 16-foot height cannot be denied due to lot coverage, FAR, or open space requirements.

Detached ADUs exceeding 16 feet in height may be subject to additional design requirements. State law requires counties to allow at least 16 feet for single-story ADUs and 18-20 feet near transit or for matching roof pitches. Specific height limits vary by zoning district.

Two-story ADUs may be permitted in some areas, subject to height limits and design review. Additional setbacks or design features may be required for second-story structures to protect neighbor privacy.

State law limits rear and side setbacks to no more than 4 feet for ADUs. Conversions of legally established structures are exempt from setback requirements. Front setbacks and other requirements vary by zoning district.

Building separation requirements follow California Building Code standards, typically requiring adequate space for fire safety and maintenance access.

The County must review complete ADU applications within 60 days as required by state law. Overall, expect 2-4 months from application to permit issuance. Rural properties may require additional reviews for water, septic, and access.

Permit costs vary based on project scope. ADUs under 750 square feet qualify for reduced or waived impact fees per state law. Contact the County Planning Department for current fee schedules.

Requirements vary by area. Rural unincorporated areas may require soils reports, septic system evaluation, or well capacity assessment. Urban unincorporated areas typically have fewer requirements. Consult with County Planning early in your process.

Parking requirements for ADUs are limited by state law. No parking is required within half a mile of transit. Where required, parking cannot exceed one space per ADU. Replacement parking is not required for garage conversions.

No. California state law prohibits counties from requiring replacement parking when a garage is converted to an ADU.

If parking is required, it can be located in setback areas, existing driveways, or elsewhere on the property. Tandem parking is typically permitted.