Marin County · Building on your lot
Building on your lot in Marin County
Marin County's code applies only in unincorporated areas of the county. It sets coastal-zone limits for accessory structures and rules on home-business visits and licenses.
Key points
- Accessory height: County rule: in the coastal zone, detached residential accessory structures are limited to 15 ft in height.
- Home businesses: County rule: home businesses need a business license and may have no more than 1 client appointment at a time.
Each rule below is marked Marin County code or CA state law and links to the section it comes from (checked October 2026). General information, not legal advice.
Marin County's code applies in the unincorporated areas of the county. Cities in Marin County have their own codes and their own pages.
Sheds, garages and other accessory structures
Marin County code County rule: in the coastal zone, detached residential accessory structures are limited to 15 ft in height.
All 4 Marin County rules on sheds, garages and other accessory structures, with the code text →
Running a business from home
Marin County code County rule: home businesses need a business license and may have no more than 1 client appointment at a time.
All 5 Marin County rules on running a business from home, with the code text →
Solar panels and EV chargers
| Solar height and setbacks |
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Tree removal
Marin County code Exempt if disease, damage or age makes long-term survival of the tree unlikely. Exempt if a pathogen or insects threaten nearby trees, as an arborist report or qualified professional finds.
All 8 Marin County rules on tree removal, with the code text →
Pets, chickens and bees
| Pet limit |
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Building in a flood zone
Marin County code Permit applications for construction, substantial improvements, grading, paving, mining, drilling or manufactured homes are reviewed for flood-prone areas. No fill, construction or other encroachment unless a registered civil engineer certifies it will not raise base flood levels.
All 4 Marin County rules on building in a flood zone, with the code text →
Grading and erosion control
Marin County code You need a grading permit to move over 250 cubic yards of earth. Cut and fill slopes may be no steeper than 2 to 1.
All 3 Marin County rules on grading and erosion control, with the code text →
Building on a hillside
| When hillside rules apply |
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Family child care homes
| Zoning | A small or large family child care home is a residential use and a use by right under all local ordinances, including zoning |
|---|---|
| Business license or fee | A city or county may not charge a business license, fee or tax to run a family child care home |
| Local rules | Local limits on height, setbacks, lot size, health and safety must be the same as for every other home in the same zone |
| Small home | Up to eight children, counting the provider's own children under 10 who live there |
| Large home | 7 to 14 children, counting the provider's own children under 10 who live there |
Group homes and residential care
Marin County code Use Permit approval is required. A permitted use.
All 4 Marin County rules on group homes and residential care, with the code text →
Parking spaces required for homes
Marin County code 1 guest space per 5 dwelling units. 1 guest space per 5 units.
All 14 Marin County rules on parking spaces required for homes, with the code text →
Signs on homes
Marin County code Up to 16 square feet per lot. No limit on the number of signs, but total sign area may not exceed 16 square feet.
All 5 Marin County rules on signs on homes, with the code text →
Trash and recycling carts
| Where carts are kept |
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Other Marin County rules on this
Marin County's code also has these chapters. We have not summarized their values on this page yet; read them in the library.
- SB 9 housing development standards (§ 22.32.184)
- SB 9 urban lot splits (§ 22.80.064)
- No parking of oversized vehicles (§ 15.36.091) — on public streets with posted signs
- Living in campers, house cars and trailers (Ch. 7.52)
- Loud and unnecessary noise (Ch. 6.70)
- Public transportation facilities fees (Ch. 15.07)
Who this affects
Frequently asked questions
What extra rules apply to a hillside lot in Marin County?
Marin County's code: Hillside standards apply on sites with a slope of 6 percent or greater. (Subdivisions and other development on such sites.) (§ 22.20.070).
Can I run a family child care home in Marin County?
California law sets this for every city, including Marin County: Zoning: A small or large family child care home is a residential use and a use by right under all local ordinances, including zoning (Health & Safety Code § 1597.45(a)); Business license or fee: A city or county may not charge a business license, fee or tax to run a family child care home (Health & Safety Code § 1597.45(b)); Local rules: Local limits on height, setbacks, lot size, health and safety must be the same as for every other home in the same zone (Health & Safety Code § 1597.45(e)); Small home: Up to eight children, counting the provider's own children under 10 who live there (Health & Safety Code § 1596.78(c)); Large home: 7 to 14 children, counting the provider's own children under 10 who live there (Health & Safety Code § 1596.78(b)).
When can trash carts go out to the curb in Marin County?
Marin County's code: Keep carts on the premises. (Carts must not be kept on a public street, sidewalk or public place, except on collection days in the designated collection location.) (§ 7.00.100).
General information, not legal advice.
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