Napa ADU Requirements

Zones Allowed

One ADU is allowed on any lot zoned for residential uses that includes an existing or proposed single family or multi-family dwelling unit. One JADU is also permitted per lot zoned for single-family dwellings when it is developed or proposed to be developed with a single-family dwelling.

Lot Restrictions

Single family dwellings: One ADU or JADU is permitted per lot developed with a single-family dwelling unless the ADU is a detached ADU, in which case a JADU is also permitted. Multifamily dwellings: ADUs may be constructed on lots developed with multifamily dwellings in accordance with California Government Code Section 65852.2(e).

Minimum Lot Size

None

Min/Max ADU Size

• Minimum: None
• Both Attached and Detached: Maximum of 1,200 square feet
• JADUs up to 500 square feet in size and fully within an existing home

ADU Building Height

Detached ADU Building Height: 16 feet. Height may be the maximum height for the zoning district allowed with Administrative Permit. Attached ADU Building Height: Maximum height allowed for the zoning district.

Setbacks

• Same setbacks as primary unit for attached ADUs
• 4 ft side and rear lot line setback for detached or above garage ADUs
• No additional setback for conversion of existing garage

Parking Requirements

One parking space per ADU. No parking required if:

• Within 0.5 miles walking distance of a public transit stop
• In a designated historic district
• In part of a principal dwelling unit or an existing accessory structure
• In an area requiring on-street parking permits but the permits are not offered to the ADU occupant
• Within one block of a car-sharing pickup/drop-off location

Also, when a garage or other parking structure or area is demolished in conjunction with the construction of an ADU or converted to an ADU, replacement of the lost parking is not required.

Owner Occupancy

Required only for JADUs

Kitchen Requirements

ADUs shall have a full kitchen. JADUs shall have at minimum an efficiency kitchen.

Process

Detached ADUs exceeding 16 feet in height or on historic properties require Planning Division entitlements. All other ADUs apply directly with the Building Division.

Disclaimer: standards and process may vary. Consultation with the contact is recommended before starting any project.

Additional JADU Requirements

• Must be constructed within the walls of the existing or proposed principal dwelling unit
• May contain separate sanitation facilities or may share sanitation facilities with the principal dwelling unit
• Must include a separate entrance from the main entrance to the existing or proposed principal dwelling unit
• The property owner shall reside in either the principal dwelling unit or the JADU
• Prior to issuance of a building permit for the JADU, a deed restriction must be filed with the County Recorder