Contra Costa County · Building on your lot

Building on your lot in Contra Costa County

In unincorporated Contra Costa County, the county code limits home businesses and requires a permit for fences and plantings in a public right-of-way. A home business that goes beyond the basic limits needs a land use permit.

Ask about building on your lot in Contra Costa County See coverage

Key points

Home businesses: County code: home businesses are limited to one room or 20% of floor area, whichever is greater, with no clients and only resident workers.
Right-of-way fences: County code: a hedge, planting, fence or similar structure in a public right-of-way needs a permit unless a Section 1002-8.042 exception applies.

Each rule below is marked Contra Costa County code or CA state law and links to the section it comes from (checked October 2026). General information, not legal advice.

Contra Costa County's code applies in the unincorporated areas of the county. Cities in Contra Costa County have their own codes and their own pages.

Fences and walls

Contra Costa County code What Contra Costa County's code adds
Permit	Yes. A permit is needed to plant, build or keep a hedge, fence or similar structure, unless an exception applies. Applies: Only hedges, plantings, fences or similar structures in a public right-of-way. § 1002-8.038 · code text No hedge, shrub, or other planting whatever, or fence or similar structure, except as provided in Section 1002-8.042, shall be planted, erected, or maintained in a right-of-way without a permit.

Running a business from home

Contra Costa County code County code: home businesses are limited to one room or 20% of floor area, whichever is greater, with no clients and only resident workers.

All 11 Contra Costa County rules on running a business from home, with the code text →

Solar panels and EV chargers

Contra Costa County code What Contra Costa County's code adds
Solar height and setbacks	A rooftop system may not be taller than the building height limit of its zoning district. Applies: Required for expedited review as a small residential rooftop system: a detached single-family home or duplex, no larger than 10 kilowatts. § 718-12.004 · code text The system, when installed on a rooftop, does not exceed the building height limit of the zoning district in which it is located.
Solar permit process	Expedited building permit; you may apply electronically; the system may not run until the building official verifies it in writing. Applies: Applies to small residential rooftop solar systems. The permit is issued after approval and payment of fees. § 718-12.004 · code text The following expedited, streamlined permitting process applies to applications for a building permit to install a small residential rooftop solar energy system:

Tree removal

Contra Costa County code No tree permit is needed for a hazard that requires immediate action. No tree permit is needed when removal was specifically approved in a development plan, subdivision, discretionary project or building permit.

All 10 Contra Costa County rules on tree removal, with the code text →

Pets, chickens and bees

Contra Costa County code What Contra Costa County's code adds
Large animals	Shelters at least 100 feet from front line and streets, 50 feet from side/rear lines; pens 10 feet from lines. Applies: Livestock only on contiguous lots of at least 40,000 square feet, with at most 2 head per 40,000 square feet. § 82-50.408 · code text Barns, stables, and other buildings or structures used to shelter livestock must be set back at least one hundred feet from the front property line and all streets, and must be set back at least fifty feet from all side and rear property lines. Fenced pasture, paddocks, or other enclosed livestock areas must be located at least ten feet from all property lines.

Building in a flood zone

Contra Costa County code A county public works floodplain permit is needed before construction, a grading or building permit, or any development. At or above base flood elevation plus 2 feet in the San Francisco Bay Delta Estuarine Region, 1 foot elsewhere.

All 3 Contra Costa County rules on building in a flood zone, with the code text →

Grading and erosion control

Contra Costa County code What Contra Costa County's code adds
Steepest cut or fill slope	No steeper than 1 vertical to 2 horizontal. Applies: Cuts, unless a soil engineering or geology report shows a steeper cut will be stable. § 716-8.202 · code text Cuts shall not be steeper in slope than one vertical to two horizontal unless the applicant furnishes a soil engineering or an engineering geology report, or both, certifying that the site has been investigated and giving an opinion that a cut at a steeper slope will be stable and not create a hazard to public or private property.

Park and impact fees for new homes

Contra Costa County code Second units are not counted as dwelling units. The number of homes times the fee per unit.

All 12 Contra Costa County rules on park and impact fees for new homes, with the code text →

Family child care homes

CA state law California law
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)

Affordable units in new housing (inclusionary)

Contra Costa County code The Board of Supervisors sets the in-lieu fee in the Department of Conservation and Development's fee schedule. Fee is the difference between the targeted household's affordable price and the county median single-family sale price (prior 12 months).

All 9 Contra Costa County rules on affordable units in new housing (inclusionary), with the code text →

Home alarm permits and false alarms

Contra Costa County code 20 minutes. A false alarm fee applies.

All 5 Contra Costa County rules on home alarm permits and false alarms, with the code text →

Signs on homes

Contra Costa County code What Contra Costa County's code adds
Signs that need no permit	Temporary sign needs no permit. Applies: Applies if kept up for no more than 60 consecutive calendar days and not over 12 square feet or 6 feet high. § 88-6.606 · code text A temporary sign maintained for a period not to exceed 60 consecutive calendar days. The temporary sign may not exceed 12 square feet in area. The temporary sign may not exceed six feet in height.

Trash and recycling carts

Contra Costa County code What Contra Costa County's code adds
Required collection service	Must subscribe with a collector for collection and disposal of solid waste. § 418-6.008 · code text Every owner and/or person required by Section 418-6.006 hereof to provide and keep containers shall, except as provided in Section 418-6.0 12, subscribe with a collector for the collection and disposal of solid waste
Where carts are kept	Keep containers in a place readily accessible to the collector, where they will not be a public nuisance or offensive. Applies: Applies to dwelling houses and other listed premises (hotels, restaurants, boardinghouses and similar). § 418-6.006 · code text Every owner, proprietor, manager or other person having charge or control of any hotel, club, bar, restaurant or other eating place, or any boardinghouse, lodginghouse, dwelling house, or any vegetable or food processing and handling establishment shall provide and keep at all times, in a place readily accessible to the collector and where it will not be public nuisance or be offensive, a container

Other Contra Costa County rules on this

Contra Costa County's code also has these chapters. We have not summarized their values on this page yet; read them in the library.

Two-unit homes on single-family lots (SB 9) (Ch. 88-36)

Who this affects

HomeownersContractorsDesigners

Frequently asked questions

How tall can a fence be in Contra Costa County?

County code: a hedge, planting, fence or similar structure in a public right-of-way needs a permit unless a Section 1002-8.042 exception applies.

Do I need a permit for solar panels or an EV charger in Contra Costa County?

Contra Costa County's code: Expedited building permit; you may apply electronically; the system may not run until the building official verifies it in writing. (Applies to small residential rooftop solar systems. The permit is issued after approval and payment of fees.) (§ 718-12.004).

What are the grading rules in Contra Costa County?

Contra Costa County's code: No steeper than 1 vertical to 2 horizontal. (Cuts, unless a soil engineering or geology report shows a steeper cut will be stable.) (§ 716-8.202).

Can I run a family child care home in Contra Costa County?

California law sets this for every city, including Contra Costa 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)).

What signs may I put up at my home in Contra Costa County?

Contra Costa County's code: Temporary sign needs no permit. (Applies if kept up for no more than 60 consecutive calendar days and not over 12 square feet or 6 feet high.) (§ 88-6.606).

When can trash carts go out to the curb in Contra Costa County?

Contra Costa County's code: Must subscribe with a collector for collection and disposal of solid waste. (§ 418-6.008); Keep containers in a place readily accessible to the collector, where they will not be a public nuisance or offensive. (Applies to dwelling houses and other listed premises (hotels, restaurants, boardinghouses and similar).) (§ 418-6.006).

General information, not legal advice.

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