Napa, California

Zoning

All properties zoned for single family, two-family or multifamily may be eligible to build ADUs.

Number of units

The number of ADUs you’re able to build depends on how your lot is zoned:

• Lots zoned for single family use may add 1 ADU and 1 Jr. ADU (JADU).
• Lots zoned for two-family or multi-family may add up to 2 detached ADUs per lot or up to 25% of the existing units in the building if conversions of existing non-living space.

Building size

The maximum ADU you can build depends on the ADU type:

• The maximum size is 500 sq. ft. for a JADU
• 1,200 sq. ft. for a detached ADU
• Attached ADUs may not exceed 50% of the primary dwelling floor area, up to 1,200 sq. ft. maximum

Building height

Detached ADUs can reach a maximum height of 16 feet. Attached ADUs maximum height is the same as the underlying district.

Setbacks

Minimum setbacks of 4 feet from the side and rear lot lines.

Parking

One parking spot required unless any of the following true:

• The accessory dwelling unit is located within one-half mile walking distance of public transit.
• The accessory dwelling unit is located within an architecturally and historically significant historic district.
• The accessory dwelling unit is part of the proposed or existing primary residence or an accessory structure.
• When on-street parking permits are required but not offered to the occupant of the accessory dwelling unit.
• When there is a car share vehicle located within one block of the accessory dwelling unit.

Owner-occupancy

Owner occupancy is not a requirement for permitting an ADU from January 1, 2020 until January 1, 2025. This is a great opportunity for rental property owners to increase their yields in a cost-effective way.

Rental

While long-term rentals are permitted for ADUs, short-term rentals (e.g. Airbnb for less than 30 days) are not permitted in the city.

Watch-outs

Are you in a creek protection area? Do you have a utility easement over your property? Reach out to us and we’ll help you build a custom ADU to fit your unique property characteristics and local regulations!

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