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Marin County · Building on your lot

Sheds, garages and other accessory structures in Marin County

County rule: in the coastal zone, detached residential accessory structures are limited to 15 ft in height.

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Key points

  • Accessory height: County rule: in the coastal zone, detached residential accessory structures are limited to 15 ft in height.

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

What Marin County's code says

Marin County code What Marin County's code adds
Maximum height
  • A residential accessory structure can be at most 15 feet tall.
    Applies: For detached residential accessory structures in the coastal zone.
    § 20.32.130 · code text
    A residential accessory structure shall not exceed a height of 15 feet;
  • Up to the height limit for a main building in that zoning district.
    Applies: For detached accessory structures in the coastal zone at least 40 feet from every property line that meet other rules, such as public views.
    § 20.32.130 · code text
    an accessory structure may be constructed to the maximum height allowed by the applicable zoning district for a primary structure, where the structure is located at least 40 feet from any property line and it meets any other applicable requirements
  • At most 30 feet tall.
    Applies: For a detached parking structure with floor area built beneath it, in the coastal zone.
    § 20.32.130 · code text
    the maximum height of the detached structure shall be 30 feet.
Size or lot coverage
  • All detached accessory structures together: no more than 30% of the required rear-yard setback area.
    Applies: In the coastal zone. More needs Design Review approval.
    § 20.32.130 · code text
    The total aggregate floor area of all detached accessory structures shall not exceed 30 percent of the area contained within the boundaries of the setback required in the rear yard except with Design Review approval

Who this affects

HomeownersContractorsDesigners

Frequently asked questions

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

County rule: in the coastal zone, detached residential accessory structures are limited to 15 ft in height.

General information, not legal advice.

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Ask GoCodebook how Marin County's sheds, garages and other accessory structures rules apply to your situation and get an answer that cites the section.

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Marin County Municipal Code — full text