Contra Costa County is an East Bay county of about 1.2 million residents, but most live inside its 19 cities. The Building Inspection Division, within the Department of Conservation and Development at 30 Muir Road in Martinez, issues building permits for the unincorporated communities and hills outside city limits and, by contract, for Clayton, Hercules, Lafayette, Moraga and Orinda.
This guide covers the Building Inspection Division’s unincorporated-area role, Title 24 with county amendments, and the seismic and hillside layers, and where city work goes instead.
This guide covers unincorporated Contra Costa County and the contract cities and towns of Clayton, Hercules, Lafayette, Moraga and Orinda. The county’s other 14 cities each run their own permitting.
Most of Contra Costa County is inside a city, so the first question is jurisdiction. The Building Inspection Division issues building permits for the unincorporated communities and hills and for five contract cities and towns — Clayton, Hercules, Lafayette, Moraga and Orinda — which still give their own planning approvals first. Work in the other 14 cities files with that city. Seismic design is central across the East Bay, and hillside parcels carry added grading review.
What requires a building permit in Contra Costa County?
Permit required
- New commercial, multi-family and residential construction, additions and change of occupancy
- Structural alterations, load-bearing changes, foundations, decks and retaining walls
- Electrical work — services, panels, circuits, solar and EV charging — under the California Electrical Code
- Plumbing under the California Plumbing Code
- Mechanical and HVAC change-outs, and work affecting the Title 24 energy envelope
- Re-roofing above the exempt scope, pools, signs, and demolition
Often exempt
- Minor repairs and maintenance replacing materials in kind
- Small accessory structures below the local threshold, where zoning allows
- Painting, flooring, cabinetry and other finish work
- Like-for-like fixture or appliance swaps with no alteration to wiring or piping
Local amendments and thresholds differ from one jurisdiction to the next, so an exempt list from a neighbouring city is not reliable — a project waved through in one place needs a full permit set in the next. An exemption from a building permit is never an exemption from zoning, the statewide energy or green-building codes, or an electrical or plumbing permit. Confirm scope with Building Inspection before work starts.
Short on time to read all of this?
Get a free quote →The statewide layers that apply everywhere
Several parts of Title 24 apply on top of the base building code and routinely catch projects owners assume are exempt: the California Energy Code (Part 6); CALGreen (Part 11), California’s mandatory statewide green-building code; and the accessibility provisions in Chapters 11A and 11B. Seismic design is built into the code statewide, and in fire-prone areas the California Wildland-Urban Interface Code (Title 24, Part 7, in force since 1 January 2026) and Cal Fire defensible-space requirements (Public Resources Code 4291) add a further layer. In unincorporated Contra Costa County, the Building Inspection Division administers Title 24 with county amendments, and seismic and hillside-grading review attach to many parcels in the hills and along the fault corridors.
California builds on one statewide code, Title 24, whose 2025 edition took effect on 1 January 2026; the editions in effect when the application is submitted apply, and cities and counties may adopt local amendments only with findings filed with the state (new residential amendments are largely frozen until June 2031). Title 24 and local amendments
Who handles permitting in Contra Costa County?
The Building Inspection Division of the Department of Conservation and Development handles building permits and inspections for unincorporated Contra Costa County and the contract cities and towns of Clayton, Hercules, Lafayette, Moraga and Orinda; the other 14 cities handle their own.
| Detail | Information |
|---|---|
| Authority | Contra Costa County Building Inspection Division |
| Serves | Unincorporated Contra Costa County, plus Clayton, Hercules, Lafayette, Moraga and Orinda by contract |
| Phone | 925-655-2704 (Building Code Hotline 925-655-2737) · 30 Muir Road, Martinez · Monday to Thursday 7:30am–5pm, Friday 7:30am–4pm |
| Portal | ePermits Center: all building applications are filed online |
| Code | Title 24 with Contra Costa County amendments |
| Seismic | Central to structural review across the East Bay |
| Layers | Hillside-grading review in the hills |
| City work | The other 14 cities issue their own permits; the five contract cities keep their own planning approvals |
The Building Inspection Division is the building authority for unincorporated Contra Costa County and the contract cities and towns of Clayton, Hercules, Lafayette, Moraga and Orinda, working from 30 Muir Road in Martinez (925-655-2704; Monday to Thursday 7:30am to 5pm, Friday 7:30am to 4pm). All building applications are filed online through the county’s ePermits Center; paper plans are no longer accepted. In the contract cities, planning approval comes from the city or town first. Seismic design is central to structural review across the East Bay, and hillside parcels add grading review.
Not sure this scope needs a permit?
Get a free quote →Confirm the jurisdiction from the parcel first; a project inside a Contra Costa County city files with that city’s department under its own code and counter.
In 2025, building permits issued in unincorporated Contra Costa County authorized 315 new privately owned housing units, 297 of them single-family homes, according to the U.S. Census Bureau Building Permits Survey.
Permit types
Residential permits
Unincorporated residential work is permitted and inspected by the county under Title 24 and county amendments. Additions, decks, pools, solar and EV chargers need permits, and hillside parcels carry grading review. A CSLB-licensed contractor in the right classification pulls the trade permits.
Commercial permits
Commercial and multi-family work in unincorporated areas goes through county plan check against the California Building Code, the Energy Code and CALGreen. It requires CSLB-licensed contractors and stamped drawings with seismic design, plus hillside grading review where slopes apply.
Licenses, trade classifications and design professionals
Practically, three credential layers appear on California projects: a CSLB license in the correct classification for the contractor pulling the permit; the specialty C-classifications for the electrical, plumbing and mechanical trades; and, on commercial and larger residential work, drawings stamped by a California-licensed architect or engineer. Confirm what Building Inspection requires for the specific building before filing.
Contractors are licensed statewide by the Contractors State License Board (Classes A, B, B-2 and C) for work of $1,000 or more or any permitted work; a city may also require a business licence or tax registration. Contractor licensing in California
Contra Costa County permit costs and fees
Budget the county building permit and plan-check fees, separate trade permits, the state Building Standards and seismic surcharges, and any hillside grading review. The county publishes a valuation-based schedule; confirm it for your filing date.
Rather talk it over?
Call 1-855-478-4290 →| Fee component | How it works |
|---|---|
| Building permit | Based on project valuation or square footage; set by the local schedule |
| Plan check | A percentage of the permit fee or a flat charge, at submittal |
| Trade permits | Separate electrical, plumbing and mechanical fees |
| State surcharges | Building Standards and seismic (SMIP) fees collected with the permit |
| Impact and school fees | Development impact and school-district fees in growth areas |
| Re-inspections and revisions | Additional fees for failed inspections, revisions and expired permits |
California layers two uniform state surcharges — the Building Standards Administration fee and the Strong Motion Instrumentation seismic fee — on top of the local charges (Health and Safety Code 18931.6; Public Resources Code 2705). The building and plan-check fees themselves are local and change, and California law limits them to the reasonable cost of providing the service, so a figure from a neighbouring city is not reliable — ask Building Inspection for the schedule in force on your filing date.
Need a real number for a specific Contra Costa County project? Send us the scope, address and valuation and we will identify the authority having jurisdiction, the code edition in force and the fee categories that will apply.
Trade permits and who may pull them
Permit required
- Service installations, panel upgrades, new circuits, solar PV and EV chargers
- New plumbing, repipes, water heater change-outs, fixtures, backflow and gas piping
- HVAC installation and change-out, ductwork, venting and commercial kitchen exhaust
- Sprinkler, standpipe and fire alarm work on commercial and multi-family structures
Typically exempt
- Replacing a fixture, switch, receptacle or light with no alteration to wiring or piping
- Clearing a stoppage without replacing or rearranging concealed piping
- Filter, thermostat and routine component service
- Like-for-like appliance repair that does not alter the connection
Each trade follows its part of Title 24 and is done by a contractor with the matching CSLB licence (C-10 electrical, C-36 plumbing, C-20 HVAC), a Class B contractor where allowed, or an owner-builder. Trade licences in California
Rather not deal with the Contra Costa County building department?
Get a free quote →How to apply for a Contra Costa County building permit
Unincorporated parcels and the five contract cities file with the county; the other 14 cities run their own.
Unincorporated applications run through the county’s online and Martinez counter systems.
California licenses contractors statewide; match the classification to the scope.
Structural and grading requirements attach to many hill parcels.
File the plan set and pay the review fees the county posts.
Issue the permit and request inspections through the county.
Review, corrections and what actually causes delay
In California, the first cause of delay is uncertainty over jurisdiction — filing with the county when a city should have it, or missing a local amendment on top of Title 24. After that come Title 24 energy and CALGreen documentation, a CSLB classification that does not match the scope, and, in fire or coastal areas, defensible-space or coastal-zone requirements that were not addressed up front. Build the plan-check time into the schedule and confirm the checklist with Building Inspection before filing.
A building permit carries a validity period and can expire if work does not start or stalls between inspections; confirm the expiry with Contra Costa County on phased or delayed work. Permit validity in California
Inspections in Contra Costa County
Where a permit is required, standard checkpoints include footing and foundation, framing, rough-in electrical, plumbing and mechanical, insulation and Title 24 energy, CALGreen measures, fire systems on commercial work, and final, with a certificate of occupancy before use. On issuance the county assigns the field inspector and the construction stages that must be inspected.
California inspections are made against the code editions in effect when the permit application was submitted (Health and Safety Code 18938.5), so the approved plans and any energy and green-building documentation need to be on site for the inspector to check against. Confirm the notice Building Inspection needs and schedule around its inspection windows.
Want this handled start to finish?
Get a free quote →Do not cover work before the required inspection has been approved. Keep the issued permit, the approved plans, product listings, Title 24 energy documentation and your correction responses available on site.
Contra Costa County permit search and official resources
Permit records in California sit with the local authority that issued them. Where the Contra Costa County Building Inspection Division is the authority for unincorporated Contra Costa County, it holds the building permit, the inspection history and the certificate of occupancy. If you are buying, refinancing or renovating, confirm that past work was permitted rather than assuming it was — and confirm the code edition that was in force.
Confirm the authority having jurisdiction and the local amendments first. California enforces one statewide code, Title 24, but each city and county adds its own amendments and fee schedule, so the requirements that apply vary by parcel. Confirm current requirements, fees and review turnaround for your filing date.
These are the primary sources behind this guide. Codes, fee schedules and procedures change — confirm the position for your filing date.
- Contra Costa County Conservation and Development
- California Building Standards Commission (Title 24)
- Contractors State License Board (CSLB)
- California Energy Commission (Energy Code)
- California Department of Housing and Community Development
Frequently asked questions
Who issues building permits in unincorporated Contra Costa County?
The Building Inspection Division of the Department of Conservation and Development, 30 Muir Road, Martinez (925-655-2704), issues building permits for unincorporated areas and for Clayton, Hercules, Lafayette, Moraga and Orinda; the county’s other 14 cities run their own departments.
Inspections are where schedules slip.
Get a free quote →Is most of Contra Costa County unincorporated?
No. Most residents live inside a city. The county is the building authority for the unincorporated communities and hills outside city limits, and also for the five contract cities and towns of Clayton, Hercules, Lafayette, Moraga and Orinda.
How does seismic design affect my project?
Seismic design is central to structural review across the East Bay; expect it to shape foundations, framing and connections on most projects.
Does my project need hillside review?
Hillside parcels commonly carry grading review; confirm the requirements with the Building Inspection Division before you file.
Do I need a local contractor registration?
Not a contractor licence: California licenses contractors statewide through the CSLB, and the licence must be active and carry the right classification. A city may still require a business licence or business tax registration (Government Code 37101), so ask the department.
How do I run a Contra Costa County permit search?
The Building Inspection Division holds unincorporated permit and inspection records; city records sit with each city’s department.
Simplify Contra Costa County permitting with Alliance Permitting
Unincorporated Contra Costa County turns on jurisdiction, seismic design and hillside grading. Clearing those before filing is most of the battle across the county’s unincorporated communities and hills.
Trusted by leading builders, developers, and national contractors — 21+ years of filing in the jurisdictions we write about.
Contractors and builders choose Alliance for Contra Costa County because the work is done by people who have stood at the counter:
- We confirm whether the parcel is unincorporated or inside a city.
- We manage the county application end to end.
- We confirm the CSLB classification matches the scope.
- We address seismic and hillside grading review up front.
- We submit complete plan sets and track issuance and inspections.
Alliance Permitting is a permit documentation and submission company in California. We prepare your paperwork, file it correctly and coordinate with the permitting authority through issuance. We are not a contractor and we do not perform licensed plan review or inspections; that work stays with your licensed team and the jurisdiction.
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More California permitting guides
This guide is provided by Alliance Permitting for general information about Contra Costa County permitting. Requirements, fees, and procedures change; confirm details with the permitting authority before relying on them.