ADU Regulations in Vacaville, California (2026)

Regulations at a glance

Local rules & notes

Site Coverage Bonus: ADUs over 800 sq ft can increase the total allowable site coverage of a lot by up to 10% above the underlying district maximum. Rear Yard Coverage Increase: The maximum rear yard coverage can be increased from 20% to 35% specifically to accommodate a new detached ADU over 800 sq ft. Entrance Door Color Matching: If an ADU entrance is on the same building frontage as the primary dwelling, the door must be painted to match the color of the adjoining wall.

For the official ordinance and latest updates, check your city or county planning department.

Frequently asked questions about ADU regulations in Vacaville

• What is the maximum ADU size in Vacaville, California?

  In Vacaville, the maximum ADU size is typically 1200 square feet, depending on whether the unit is attached or detached. California state law allows up to 1,200 sq ft for detached ADUs and 800 sq ft for attached in many jurisdictions; Vacaville may follow state defaults or have local limits. Verify with Vacaville planning for your specific lot.

• What are the setback requirements for ADUs in Vacaville?

  In Vacaville, typical setback requirements are 4 feet from the side property line and 4 feet from the rear. These may be reduced to 4 feet under California Government Code § 65852.2 where applicable. Check with Vacaville planning for overlay zones or design standards that could affect your site.

• What is the maximum height for an ADU in Vacaville?

  In Vacaville, the maximum height for an ADU is generally 16 feet. State law often allows up to 16 feet for detached ADUs and up to 25 feet when within 4 feet of the property line in some cases. Confirm with Vacaville or county planning for your zone.

• Is ADU approval ministerial in Vacaville?

  In Vacaville, ADU approval is typically Ministerial (by-right) per Gov Code §65852.2. Ministerial (by-right) review means the city must approve qualifying applications without discretionary review, per California Gov Code § 65852.2. Your project must still meet objective standards; Vacaville planning can confirm the exact process.

• Are there parking requirements for ADUs in Vacaville?

  In Vacaville, parking for ADUs is generally true. California law often waives parking for ADUs within a half-mile of transit or in certain historic districts. Check with Vacaville planning for your address.