Napa County, CA - 2026 Building Permit Guide

Permit Authority

This process applies to properties in the unincorporated areas of Napa County; properties inside Napa County cities and towns are handled by their own jurisdictions.

Department

Napa County Planning, Building & Environmental Services, Building Division

Address

1195 Third Street, 2nd Floor, Napa, CA 94559

Phone

707-253-4417

Email

building@countyofnapa.org

Website

https://www.napacounty.gov/3492/Building-Division

Online Permit Portal

Application Process

1. Confirm the parcel is in unincorporated Napa County using the County public map or property tools.
2. Identify the project type and confirm whether a permit is required. Napa County states most work requires a permit.
3. Gather the correct checklist and application package for the project type. Depending on scope, this can include the permit application, plan set, site plan, authorized agent form, construction waste plan, geotechnical materials, special inspection forms, title page materials, and other supplemental documents.
4. Create an OPC account and submit the application digitally. Since January 1, 2024, all Building Division permit applications are handled digitally through OPC.
5. Complete intake review. If the submittal is incomplete, Napa sends comments and the applicant resubmits to the same record.
6. Pay invoiced plan review fees when requested. Napa routes plans to other County divisions or agencies as needed.
7. Respond to correction comments, upload revised plans and a comment response letter, and continue resubmittals until all reviews are approved.
8. Pay final permit and inspection fees through OPC. Napa then issues the permit and emails instructions to print and post the permit card, inspection card, and approved plans at the job site.
9. Schedule inspections online, by phone, or by text as work progresses, then obtain all required finals before permit final or certificate of occupancy.

Typical processing time: Express review 3-5 business days; Quick review 7-10 business days; Standard review 28 business days. Actual timing depends on project type, size, completeness, and outside referrals.

Source: Napa County Planning, Building & Environmental Services, Building Division

General Requirements

Napa County states that most work requires a permit. Its project-types page quotes the California Building Code rule that no regulated building or structure may be erected, enlarged, altered, repaired, moved, improved, removed, converted, or demolished without a permit. Common online application types include residential and commercial submittals, HVAC replacement, reroofs, and water heater replacement.

Required Documents

• Permit application
• Plan set
• Site plan
• Authorized agent form
• Construction waste plan
• Geotechnical report materials
• Special inspection and testing documents
• Title page requirements
• WUI checklist where applicable
• Other project-specific supplemental documents required by the checklist

Permit validity

Issued permits expire if work is not started within 1 year of issuance, if work is suspended or abandoned for 180 days, or if no approved inspection is scheduled and performed for 180 days. Extension requests must be made in writing before expiration; approved extensions may be granted for up to 180 days and no request is accepted more than 30 days before expiration. Applications also expire if no permit is issued within 1 year after application.

Building code

Napa County materials state the current adopted codes include the 2022 California Administrative Code, 2022 California Building Code, 2022 California Residential Code, 2022 California Historical Building Code, 2022 California Existing Building Code, 2022 California Green Building Standards Code, 2022 California Mechanical Code, 2022 California Plumbing Code, 2022 California Electrical Code, 2022 California Energy Code, and the County of Napa Code of Ordinances.

Owner-builder

Napa requires an Owner-Builder Disclosure Form before issuing an owner-builder permit. The property owner must complete and sign it, and Napa requires ID, notarization, or other signature verification acceptable to the Building Division. An agent cannot execute the disclosure without prior County approval.

Contractor requirements

The permit application requires the applicant to state that they are either licensed under the Contractors' State License Law or exempt, consistent with Business and Professions Code section 7031.5. The owner-builder declaration on Napa's application tracks the usual California exemptions. Napa's OPC record-type guide also flags some online application types as having contractor requirements.

Fees

Minimum permit fee

The Building Division valuation table shows a minimum building inspection fee of $410 for valuations from $1.00 to $1,500. Separate issuance and plan-review-related charges also apply depending on permit type. For permits that do not require document submittals, the schedule separately lists a permit issuance fee of $54 before surcharge ($58.05 with surcharge).

Plan check fee

Plan review commonly runs as a percentage of the building inspection fee. The schedule shows many building plan review categories at 70% of the building inspection fee, with additional flat or hourly components depending on permit type.

Permit fee formula

Primarily valuation-based for building permits and plan review, using the International Building Code Building Valuation Data Table. Many permit categories also have flat or hybrid fees.

Reinspection fee

Additional inspections or reinspections are charged on an hourly basis. Outside-normal-business-hours inspection or reinspection is $372 per hour. Permit extension fee is $124 before surcharge, and permit reinstatement fee is $248 before surcharge.

Penalty (no permit)

Napa's example-fees page states that failure to obtain the proper permit before starting construction can trigger a penalty of 400% of the building inspection fee.

Payment note

Napa invoices fees during review and again before issuance, and payment instructions are sent by email for completion through OPC. County examples and the fee schedule note that listed amounts may be estimates and that referral or hourly charges can apply.

Fees change. Verify current amounts at the official fee schedule (effective July 7, 2025).

Work That Does NOT Require a Permit

• Reinforced concrete or reinforced masonry retaining walls that do not retain more than 36 inches of earth, do not support surcharge loads, and do not impound Class I, II, or III liquids
• Precast block wall systems installed per the manufacturer's listing and instructions that do not retain more than 36 inches of earth, do not support surcharge loads, and do not impound Class I, II, or III liquids
• Decay-resistant or treated-wood retaining walls that do not retain more than 24 inches of earth, do not support surcharge loads, and do not impound Class I, II, or III liquids

Important: Napa County does not publish a single consolidated exempt-work list on its main Building Division pages, and it expressly says most work requires a permit. Because Napa enforces the adopted 2022 California codes and project-specific referrals, exemptions are narrow and highly fact-specific. Floodplain, fire, environmental health, grading, zoning, access, right-of-way, and similar approvals may still apply even where a building permit is not required. Napa tells applicants to contact the Building Division if they are unsure whether a permit is required.

Inspections

How to Schedule

• OPC portal (online)
• Online scheduling guide (online)
• 707-253-4416 (phone)
• 866-307-2630 (text)
• 707-253-4417 (phone)

Scheduling deadline

For estimated inspection time or same-day confirmation, Napa instructs applicants to call 707-253-4417 on the morning of the inspection between 7:45 AM and 8:30 AM.

Inspection hours

Building Division office hours are Monday-Friday, 8:00 AM-5:00 PM; permit counter walk-in hours are Monday-Friday, 8:00 AM-4:00 PM.

Typical inspection sequence: The permit card identifies required inspections. Napa requires periodic inspections as work progresses, prohibits work from continuing beyond each inspection point until approval is obtained, and requires all other referred department finals before scheduling the Building Permit Final.

Additional Resources

• Building code: Napa County materials state the current adopted codes include the 2022 California Administrative Code, 2022 California Building Code, 2022 California Residential Code, 2022 California Historical Building Code, 2022 California Existing Building Code, 2022 California Green Building Standards Code, 2022 California Mechanical Code, 2022 California Plumbing Code, 2022 California Electrical Code, 2022 California Energy Code, and the County of Napa Code of Ordinances.
• Verify contractor license: CSLB License Lookup
• Zoning information: View zoning info
• Zoning Map
• Property and Map Information
• Building Permit Process
• Building Forms and Checklists
• Fee Examples for Common PBES Projects
• License lookup guide: California Contractor License Requirements
• Contract template: California Homeowner-Contractor Agreement
• California hub: California Contractor License & Permit Hub

Frequently Asked Questions

Napa County Building Permit FAQ

Do I need a building permit in unincorporated Napa County, CA?

Napa County states that most work requires a permit. Its project-types page quotes the California Building Code rule that no regulated building or structure may be erected, enlarged, altered, repaired, moved, improved, removed, converted, or demolished without a permit. Common online application types include residential and commercial submittals, HVAC replacement, reroofs, and water heater replacement.

How much does a building permit cost in unincorporated Napa County, CA?

The minimum permit fee is The Building Division valuation table shows a minimum building inspection fee of $410 for valuations from $1.00 to $1,500. Separate issuance and plan-review-related charges also apply depending on permit type. For permits that do not require document submittals, the schedule separately lists a permit issuance fee of $54 before surcharge ($58.05 with surcharge).. Fees are calculated as: Primarily valuation-based for building permits and plan review, using the International Building Code Building Valuation Data Table. Many permit categories also have flat or hybrid fees.. Plan check fee: Plan review commonly runs as a percentage of the building inspection fee. The schedule shows many building plan review categories at 70% of the building inspection fee, with additional flat or hourly components depending on permit type..

How do I apply for a building permit in unincorporated Napa County, CA?

1. Confirm the parcel is in unincorporated Napa County using the County public map or property tools. 2. Identify the project type and confirm whether a permit is required. Napa County states most work requires a permit. 3. Gather the correct checklist and application package for the project type. Depending on scope, this can include the permit application, plan set, site plan, authorized agent form, construction waste plan, geotechnical materials, special inspection forms, title page materials, and other supplemental documents. 4. Create an OPC account and submit the application digitally. Since January 1, 2024, all Building Division permit applications are handled digitally through OPC. 5. Complete intake review. If the submittal is incomplete, Napa sends comments and the applicant resubmits to the same record. 6. Pay invoiced plan review fees when requested. Napa routes plans to other County divisions or agencies as needed. 7. Respond to correction comments, upload revised plans and a comment response letter, and continue resubmittals until all reviews are approved. 8. Pay final permit and inspection fees through OPC. Napa then issues the permit and emails instructions to print and post the permit card, inspection card, and approved plans at the job site. 9. Schedule inspections online, by phone, or by text as work progresses, then obtain all required finals before permit final or certificate of occupancy.

How long does it take to get a building permit in unincorporated Napa County, CA?

Typical processing time is Express review 3-5 business days; Quick review 7-10 business days; Standard review 28 business days. Actual timing depends on project type, size, completeness, and outside referrals..

What work is exempt from building permits in unincorporated Napa County, CA?

The following work is generally exempt: Reinforced concrete or reinforced masonry retaining walls that do not retain more than 36 inches of earth, do not support surcharge loads, and do not impound Class I, II, or III liquids; Precast block wall systems installed per the manufacturer's listing and instructions that do not retain more than 36 inches of earth, do not support surcharge loads, and do not impound Class I, II, or III liquids; Decay-resistant or treated-wood retaining walls that do not retain more than 24 inches of earth, do not support surcharge loads, and do not impound Class I, II, or III liquids. Note: Napa County does not publish a single consolidated exempt-work list on its main Building Division pages, and it expressly says most work requires a permit. Because Napa enforces the adopted 2022 California codes and project-specific referrals, exemptions are narrow and highly fact-specific. Floodplain, fire, environmental health, grading, zoning, access, right-of-way, and similar approvals may still apply even where a building permit is not required. Napa tells applicants to contact the Building Division if they are unsure whether a permit is required.

How do I schedule a building inspection in unincorporated Napa County, CA?

Inspections can be scheduled via: OPC portal, Online scheduling guide, 707-253-4416, 866-307-2630, 707-253-4417. For estimated inspection time or same-day confirmation, Napa instructs applicants to call 707-253-4417 on the morning of the inspection between 7:45 AM and 8:30 AM..