Contra Costa County Permits: Costs, Inspections, and Timelines

If you’re building, remodeling, or doing significant repair work in unincorporated Contra Costa County, you’ll need building permits from the county’s Department of Conservation and Development before the work starts. The department reviews plans and inspects construction for compliance with the California Building Standards Code.¹ If your property sits inside one of the county’s 19 incorporated cities, this is the wrong office; you’ll work with that city’s building department instead. Everything below applies to unincorporated areas only.

What Work Needs a Permit

The rule of thumb is simple. If the project changes the structure, mechanical systems, electrical wiring, or plumbing of a building, pull a permit. That covers residential additions, new accessory dwelling units, garage conversions, deck construction, re-roofing, window or door replacements that alter the opening size, water heater swaps, electrical panel upgrades, and commercial tenant improvements. ADUs need both planning approval and a building permit, whether you’re building new or legalizing an existing unit.²

Some smaller work is exempt. The county’s published list, drawn from the California Residential Code, includes:

Detached one-story accessory structures of 120 square feet or less.
Fences up to 7 feet tall. Concrete and masonry walls always need a permit.
Retaining walls no more than 3 feet from the top of the footing to the top of the wall, with limited slope at the base.
Sidewalks and driveways no more than 30 inches above grade, not over a basement, and not part of an accessible route.
Painting, wallpapering, tiling, carpeting, cabinets, and countertops.
Decks up to 200 square feet, no more than 30 inches above grade, not attached to the dwelling, and not serving a required exit door.
Playground equipment at single-family or two-family homes.
Residential window awnings supported by an exterior wall, projecting no more than 54 inches.

Exempt work still has to meet the applicable building codes. The exemption only means you don’t have to pull a permit first.³

Planning Permits Are a Separate Track

A building permit authorizes the physical construction. A planning permit confirms the proposed use is allowed on the parcel under zoning. Some projects need both. Planning applications cover land use permits, variances, subdivisions, rezoning, tree removal, and wireless facilities.⁴ Ground-mounted solar systems and solar canopies need planning review before the building permit can proceed; standard rooftop solar on a permitted structure usually needs only a building permit.⁵

What to Gather Before You Apply

A complete application saves weeks. The county needs enough detail to measure your project against building, fire, and energy codes. Plan on providing:

A site plan showing property lines, existing structures, setbacks, and the footprint of the proposed work.
Floor plans and elevations drawn to scale, with dimensions, room layouts, and structural details.
Structural calculations showing the design can handle seismic loads.
Title 24 energy compliance documents. California’s Building Energy Efficiency Standards apply to all residential and nonresidential projects, and applications without them get rejected.⁶
Contractor information: a valid California contractor license number and proof of workers’ compensation insurance. California Labor Code Section 3700 requires every employer to carry workers’ compensation coverage.⁷
A clear written project description so staff can route the application correctly.

Most plans in California must be prepared and stamped by a licensed architect or engineer. The main residential exception is conventional wood-frame construction: single-family homes up to two stories, multi-family buildings with four or fewer units up to two stories, and associated garages. Anything outside that box — unusual structural systems, three or more stories, five or more units, or any commercial occupancy — needs a licensed professional. A structural engineer for a home addition typically runs $2,500 to $12,000 depending on complexity.

Older buildings add a layer. Federal NESHAP rules require an asbestos survey before demolishing or renovating commercial, industrial, and institutional buildings. Residential demolition projects should account for possible asbestos and lead paint, especially in homes built before the late 1970s, and your application may need a hazardous materials disclosure depending on the scope.

Doing the Work Yourself

If you’re not hiring a licensed contractor, you’ll sign an Owner-Builder Acknowledgement before the permit issues. California Health and Safety Code Section 19825 requires this form, and only the property owner can sign it.⁸ Read it closely. As the named party on the permit, you carry the liability. If you hire unlicensed workers and someone is injured, your homeowner’s insurance may not respond. If the total value of labor and materials reaches $500 or more and you engage anyone other than licensed contractors, you can be classified as an employer under state and federal law, bringing payroll taxes, workers’ compensation obligations, and unemployment insurance with it. You also face personal liability for construction defects if you later sell the property.

What the Permit Will Cost

Fees are calculated from the total valuation of your project — essentially the estimated market cost of labor and materials — with three components: plan review, permit processing, and inspection. Rough examples from the current fee schedule:⁹

$50,000 project: about $415 plan review, $160 permit processing, $639 inspection, for roughly $1,214 before surcharges.
$100,000 project: about $639 plan review, $246 permit processing, $983 inspection, for roughly $1,868 before surcharges.
$500,000 project: about $2,758 plan review, $483 permit processing, $3,448 inspection, for roughly $6,689 before surcharges.

Add a 40% Land Development Surcharge on top of those base amounts. The $100,000 example climbs from about $1,868 to roughly $2,615. For values above or between the tiers, per-thousand-dollar rates apply at each bracket. The county periodically adjusts the building valuation data used to calculate improvement value; the most recent adjustment added 5% effective January 1, 2025.¹⁰

New construction and larger additions also trigger school district developer fees, which vary by district. One example: the West Contra Costa Unified School District charges $5.17 per square foot for new residential construction and ADUs, and $0.84 per square foot for commercial and industrial construction.¹¹ Check with the district your property falls under for the current rate.

Submitting the Application and Getting It Reviewed

Contra Costa County has moved to 100% digital submittals for both building and planning permits. You don’t submit in person. Applications, construction plans, and supporting documents all go through the county’s ePermit Center online portal.¹² Confirm your plan files match the county’s formatting requirements before uploading; the county publishes a guide for preparing electronic plans. The DCD office at 30 Muir Road, Martinez remains open for in-person questions on other matters.¹³

After submission, the county runs an initial completeness review over roughly four to five business days.¹⁴ Incomplete packages get bounced back here, which is why clean documents matter the first time. Once the package clears, technical plan review begins. If your plans don’t meet code, you’ll get correction requests (often called redlines), you resubmit, and the cycle continues until the plans are approved. Simple projects can clear in a few weeks; complex designs take considerably longer. An application is considered abandoned if 180 days pass from the filing date without the applicant pursuing it or the permit being issued.¹⁵

Scheduling Inspections

Once the permit is issued and work begins, the county inspects at key stages. Schedule by calling 925-646-4108 or through the ePermit Center.¹⁶ Typical milestones are foundation, framing, and the rough-ins for electrical, plumbing, and mechanical before walls close, followed by a final.

On inspection day, all of the following must be in place:

The building permit on site.
Reviewed and stamped building plans on site.
A representative at least 18 years old present to meet the inspector.
Work actually ready for the inspection you scheduled.
Any deficiencies from prior inspections corrected.
Clear access to the work being inspected.

Miss any of those and the inspector cancels. The county charges a $150 reinspection fee when the visit is cancelled, when defective work needs extra visits beyond the first correction opportunity, or when you call for a partial inspection that should have been one trip.¹⁷ The final inspection closes the permit and confirms the finished project matches the approved plans.

How Long the Permit Lasts

A Contra Costa County building permit expires 365 days from the date of issuance if no required inspection has been approved during that time. It also expires if 365 days pass between any two approved inspections. Once a permit expires, all work has to stop until you obtain a new one.¹⁵

If you need more time, file a Permit Extension Request at least 30 days before expiration. If the permit has already lapsed without a final inspection, you’ll file a Permit Renewal Request, which is a separate process. Planning permits run on different clocks: most expire one year after issuance, subdivisions after three years, and some tree permits after six months.¹⁵

Changing Plans Mid-Project

If the design changes after the permit issues, submit a permit revision before the inspector signs off on the affected work. Revisions go through the same review process and timeline as original submittals, so build that into your schedule. Revised sheets must clearly cloud or bubble the changes and cannot carry any previous county stamps.¹⁵ One timing trap: don’t schedule the final inspection while a revision is still under review. If the project is finaled before the revision issues, the permit locks and the revision scope can’t be applied to it. Covering that work would require an entirely new permit and additional fees.

What Happens If You Skip the Permit

Unpermitted work doesn’t save money. When code enforcement discovers it, an investigation fee kicks in at double the amount of all permit fees that should have been paid, with a $300 minimum. That’s on top of the permit fees themselves, which you still have to pay to bring the work into compliance.¹⁸ Zoning violations carry a separate $300 minimum fee, and the county charges $150 for each additional site visit until the violation is resolved. All of these have to be paid in full before the county will issue any permits on the affected parcel.

Licensed contractors face a second set of consequences through the Contractors State License Board. Working without a required permit violates California Business and Professions Code Sections 7110 and 7090 and can bring civil penalties up to $8,000 per violation, mandatory payment of all permit fees and local penalties, and suspension or revocation of the license.¹⁹

Beyond the fines, unpermitted work follows the property. It can complicate a sale, raise lender concerns on refinancing, and leave you personally liable if someone is hurt because of work that was never inspected. The county prioritizes voluntary compliance and often gives time to correct the situation, but ignoring a Notice to Comply escalates matters into citations, administrative actions, or abatement.

1
Contra Costa County, CA Official Website. Conservation and Development
2
Contra Costa County, CA Official Website. Accessory Dwelling Units
3
Contra Costa County, CA Official Website. Construction Work Not Requiring a Building Permit
4
Contra Costa County, CA Official Website. Planning Applications
5
Contra Costa County, CA Official Website. Power Permits – Solar, Generators, Energy Storage, EV Chargers
6
California Energy Commission. Building Energy Efficiency Standards
7
California Legislative Information. California Code LAB 3700 – Compensation Insurance and Security
8
Contra Costa County, CA Official Website. Owner-Builder Acknowledgement and Verification of Information
9
Contra Costa County, CA Official Website. Land Development Fee Schedule
10
Contra Costa County, CA Official Website. Payment Information
11
West Contra Costa Unified School District. Developer Fees
12
Contra Costa County, CA Official Website. Submitting Your Online Permit Application
13
Contra Costa County, CA Official Website. Contact, Location, and Hours
14
Contra Costa County, CA Official Website. Building or Grading Permit Overview
15
Contra Costa County, CA Official Website. Permit Revisions, Extensions, and Renewals
16
Contra Costa County, CA Official Website. Inspection Schedule and Permit Status
17
Contra Costa County, CA Official Website. Inspections
18
Contra Costa County, CA Official Website. Code Enforcement
19
Contractors State License Board. Building Permit Violation Referral