Walnut Creek Building Permits Guide for Homeowners

Last updated November 13, 2026. Reviewed by the Cash Home Buyers CA team.

Walnut Creek requires a building permit whenever you add a structure or physically change your property, and every permit application goes through the city’s online portal. Paper and emailed applications are no longer accepted.

Walnut Creek permits at a glance

Apply	Online Permit Portal only
Building permits and code questions	(925) 943-5834, BuildingTech@walnutcreekca.gov
Typical permit projects	New structures, additions, ADUs and JADUs, kitchen or bathroom remodels, water heaters, window replacement, decks, HVAC, re-roofing
After-hours work	Construction on Saturdays and City holidays requires an after-hours permit

Tips for applying

The city recommends a desktop or laptop with Google Chrome or Microsoft Edge, since the portal is not mobile friendly. Fees are calculated from the city’s published fee schedule. The permit application date determines which building codes apply to your project.

Unpermitted ADUs

Walnut Creek lists an ADU Amnesty Program (AB 2533) for qualifying units. The city’s page notes that owners need to show the unit existed and that no open code enforcement or other departmental violations are present. See the city’s page for the full list.

When a Walnut Creek project needs a building permit

The city says a building permit is required when you add a structure to your property or physically change it, for both residential and commercial property.

Its examples show how wide the rule is: new buildings and structures, additions, accessory and junior dwelling units, kitchen and bathroom remodels, new or relocated lighting, water heaters and ceiling fans, replacing windows, decks, new or replaced HVAC systems and re-roofing. Construction on Saturdays and city holidays also needs an after-hours permit.

Some work does not need a permit, and the city points to a separate page that lists it. If you are unsure, confirm with the Building Division before you start rather than after a buyer’s inspector asks.

How applications work

Walnut Creek accepts every permit type through its Online Permit Portal. The city states that paper and emailed applications are no longer accepted. It also notes that the portal is not mobile-friendly and works best on a desktop or laptop using Google Chrome or Microsoft Edge.

Fees are calculated under the city’s fee schedule, which is published on its website rather than quoted on the permits page. Questions go to the permit technicians at (925) 943-5834 or buildingtech@walnutcreekca.gov.

Where to apply	Online Permit Portal only
Phone	(925) 943-5834
Email	buildingtech@walnutcreekca.gov
After-hours work	Separate after-hours permit for Saturdays and city holidays
Holiday closure	City services closed December 24, 2026 through January 3, 2027; submit by December 15, 2026 for processing before the closure, and expect 5 to 7 extra business days afterward

If you plan to finish permitted work before listing, the holiday closure above is worth building into your timeline.

Walnut Creek’s ADU amnesty program (AB 2533)

Under state law AB 2533, which took effect on January 1, 2025, Walnut Creek lets owners legalize unpermitted ADUs and JADUs built before January 1, 2020. There must be no open code enforcement or other department violations on the unit. To prove the build date, the city accepts one or more of these documents:

• The County Assessor’s initial date recognizing the unit
• Escrow documents that identify the unit and year of construction
• Prior official building, planning or code enforcement records
• A real estate transfer disclosure form that discloses the unpermitted unit
• Where none of those exist, a combination of insurance documents, notarized letters from previous owners or tenants, and dated photos

1. Confirm eligibility. Gather the documentation and confirm there are no open violations.
2. Substandard housing checklist. A licensed contractor completes the confidential AB 2533 checklist, and any substandard items are addressed in the plans.
3. Submit. Prepare a Plans file (cover sheet, site plan, floor plans, elevations, foundation, framing and lateral force details) and a Supplemental file (construction date documents and the checklist) and submit through the online portal.
4. Permit issuance. Detached ADUs also go to the Contra Costa County Fire Protection District. The inspector verifies the checklist at the first inspection, and concealed conditions may require removing finish materials.
5. Final. After final inspection and release of all department holds, the unit is legalized. Outstanding fees must be paid before the permit is issued.

Questions about the program go to buildingtech@walnutcreekca.gov with "AB 2533 Inquiry" in the subject line.

What this means when you sell

Buyers and lenders look for permits on remodels, additions and converted space. Mention in your disclosures any work you know was done without a permit.

Under California Civil Code section 1102.1, an as-is sale does not waive the transfer disclosure statement or your duty to disclose material facts, and a disclosure delivered after an offer can let the buyer cancel within three days of in-person delivery or five days of mailing. See our statewide guide to selling as-is with unpermitted work.

Two ways to approach a sale

• Fix first: pull permits, complete inspections or use the amnesty program, then list. This can widen your buyer pool but takes time and money.
• Sell as-is: disclose what you know and sell to a buyer who accepts the property in its current condition, with no corrective work on your side.

Natural hazard disclosure for a Walnut Creek home

Alongside permit history, California requires sellers to disclose whether a property sits in any of six natural hazard zones: a special flood hazard area (FEMA Zone A or V), an area of potential flooding from a dam, a very high fire hazard severity zone, an earthquake fault zone, a seismic hazard zone or a wildland area in a state responsibility zone.

The seller, or the seller’s agent, is responsible for making the disclosure, and a waiver is void as against public policy. If the disclosure reaches the buyer after an offer, they can cancel within the section 1102.3 window. Our natural hazard disclosure guide explains the details.

Budgeting for a sale after permit work

If you finish permits or legalize a unit first, add those costs to the usual seller expenses. The county documentary transfer tax is $0.55 per $500 of value, and a city that imposes its own can add half that amount; a $600,000 sale carries $660 at the county rate.

Loan payoff, escrow and title charges, any agreed commission and the proration of your property tax bill come out of proceeds. See the seller closing costs guide for the full breakdown.

• Gather permit finals, the AB 2533 documents if you legalize a unit, and prior disclosures.
• Get a lender payoff statement for your closing date.
• Ask escrow for an itemized seller estimate before you accept an offer.

How to sell a house in Walnut Creek

1. Review which improvements were permitted.
2. Gather permits and final inspection records.
3. Request a no-obligation cash offer.
4. Pick your closing date.
5. Close with no repairs or permit work required.

Frequently asked questions

Can I submit a paper permit application in Walnut Creek?

No. The city states that all permit types must be applied for through the Online Permit Portal.

Do I need a permit to replace windows or a water heater?

The city lists window replacement and water heaters among the projects that need a building permit.

Can I email a permit application to Walnut Creek?

No. The city states that all permit types must be applied for through the Online Permit Portal and that paper or emailed applications are no longer accepted.

Does replacing windows or a water heater need a permit in Walnut Creek?

Yes. The city lists window replacement and water heaters among the work that requires a building permit.

Which unpermitted ADUs qualify for Walnut Creek’s amnesty program?

Unpermitted ADUs and JADUs built before January 1, 2020 that have no open code enforcement or other department violations.

More guides

• We Buy Houses in Contra Costa County
• Contra Costa County Property Tax Guide
• Walnut Creek Code Enforcement Guide
• All California Guides

Sources

• City of Walnut Creek: Building Permits
• City of Walnut Creek: ADU Amnesty Program

This guide is general information from public sources, not legal advice. Confirm current rules with the City of Walnut Creek.