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Napa County · Building on your lot

Sheds, garages and other accessory structures in Napa County

County rule: rear-yard garages and accessory buildings are limited to 15 ft at the ridgeline and 50% of the rear yard.

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Key points

  • Accessory buildings: County rule: rear-yard garages and accessory buildings are limited to 15 ft at the ridgeline and 50% of the rear yard.

Each rule below links to the section of the Napa County Municipal Code it was read from, with the code text one click away (checked October 2026). General information, not legal advice.

What Napa County's code says

Napa County code What Napa County's code adds
Maximum height
  • No more than 15 feet at the ridgeline.
    Applies: Detached garages, accessory buildings or solar panel systems in a rear yard.
    § 18.104.140 · code text
    a detached garage, accessory building, or solar panel system not exceeding fifteen feet in height at the ridgeline may occupy not more than fifty percent of the area of a rear yard.
Size or lot coverage
  • No more than 50% of the rear yard area.
    Applies: Detached garage, accessory building or solar panel system up to 15 feet tall at the ridgeline.
    § 18.104.140 · code text
    a detached garage, accessory building, or solar panel system not exceeding fifteen feet in height at the ridgeline may occupy not more than fifty percent of the area of a rear yard.
Side and rear setback
  • At least 5 feet from the side and rear lot lines.
    Applies: Rear-yard accessory structure up to 15 feet tall that is at least 70 feet from any street.
    § 18.104.140 · code text
    If such a structure is situated not less than seventy feet from any street it may be located not closer than five feet from the side and/or rear lot lines.
  • At least 20 feet from the side and rear property lines.
    Applies: Structures accessory to agriculture, other than fences, in the residential country zoning district.
    § 18.104.140 · code text
    structures in the residential country zoning district accessory to agriculture, other than fences, shall be located at least twenty feet from the side and rear property line and fifty feet from the front property line.
Distance from the house
  • At least 8 feet from the main building.
    Applies: Garage, carport or other accessory building that does not share a wall with the main building.
    § 18.104.140 · code text
    A garage, carport or other accessory building not having a common wall with the main building shall not be placed closer than eight feet from the main building.

Who this affects

HomeownersContractorsDesigners

Frequently asked questions

How big can a shed or accessory building be in Napa County?

County rule: rear-yard garages and accessory buildings are limited to 15 ft at the ridgeline and 50% of the rear yard.

General information, not legal advice.

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Napa County Municipal Code — full text