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.

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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 What Contra Costa County's code adds
Space used	No more than 1 room or 20% of the floor area, whichever is greater. Applies: A home occupation carried out entirely inside a home. § 82-40.012 · code text No more than one room, or twenty percent of the floor area, whichever is greater, may be used for the home occupation.
Customer visits	Only 1 student may be present at one time. Applies: Students who come for individual instruction at the home. § 82-40.012 · code text If student visits occur, only one student may be present at one time, no more than six student visits may occur per day, and students may be present only between eight a.m. and six p.m. No more than 6 student visits per day. Applies: Students who come for individual instruction at the home. § 82-40.012 · code text If student visits occur, only one student may be present at one time, no more than six student visits may occur per day, and students may be present only between eight a.m. and six p.m. No clients or customers may come to the home business. Applies: The general rule. Students who come for individual instruction are the exception. § 82-40.012 · code text No clients or customers are permitted at the site of the home occupation, except for students engaged in individual home instruction.
Employees	Only the people who live in the home may take part in the business. Applies: The general rule, except where state law provides otherwise. § 82-40.012 · code text Only the residents of the dwelling unit may be involved in the conduct of the home occupation, except as otherwise provided by state law.
Permit	A home occupation permit is required. Applies: The county approves it ministerially, only when the business meets the standards. § 82-40.012 · code text An application for a home occupation permit will be ministerially approved only if it complies with the following standards in addition to the standards specified in Section 82-40.010: A land use permit is required. Applies: When any part of the home business takes place outdoors. § 82-40.014 · code text A land use permit is required for a home occupation if any of the following occur: (1) Any portion of the home occupation activity is conducted outdoors. A land use permit is required. Applies: When the business takes place in an accessory building that meets the accessory structure setback rules. § 82-40.014 · code text (2) The home occupation is conducted within an accessory building that complies with accessory structure setback requirements. A land use permit is required. Applies: When 1 or more employees of the business do not live in the home. § 82-40.014 · code text (3) One or more employees of the home occupation are not residents of the dwelling unit. A land use permit is required. Applies: When more than 1 student is present at a time, or there are more than 6 student visits per day. § 82-40.014 · code text (3) The number of student visits exceeds the amounts specified in subsection (c) of section 82-4.012. A land use permit is required. Applies: When 2 or more business vehicles are used or kept at the home. § 82-40.014 · code text (4) Two or more business-related vehicles are used or kept at the site of the home occupation.

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 and the state law underneath →

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.

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.

Can I run a business from my home in Contra Costa County?

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

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

Contra Costa County's code: A rooftop system may not be taller than the building height limit of its zoning district. (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); 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).

Can I keep chickens or bees at my home in Contra Costa County?

Contra Costa County's code: Shelters at least 100 feet from front line and streets, 50 feet from side/rear lines; pens 10 feet from lines. (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).

General information, not legal advice.

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