On this page 6
§ 02
When a permit is required
Permit triggers and exempt work for Napa County
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.
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
- 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
- Exempt 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
- Exempt 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.
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
- 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.
- 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.
- 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.
§ 03
Application process
Typical processing: 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.
- 01 Confirm the parcel is in unincorporated Napa County using the County public map or property tools.
- 02 Identify the project type and confirm whether a permit is required. Napa County states most work requires a permit.
- 03 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.
- 04 Create an OPC account and submit the application digitally. Since January 1, 2024, all Building Division permit applications are handled digitally through OPC.
- 05 Complete intake review. If the submittal is incomplete, Napa sends comments and the applicant resubmits to the same record.
- 06 Pay invoiced plan review fees when requested. Napa routes plans to other County divisions or agencies as needed.
- 07 Respond to correction comments, upload revised plans and a comment response letter, and continue resubmittals until all reviews are approved.
- 08 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.
- 09 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 ↗
§ 04
Fee schedule
Effective July 7, 2025
Fee type
Amount
01
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).
02
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.
03
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.
04
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.
05
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.
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 periodically. Confirm at the official fee schedule ↗ (effective July 7, 2025) before budgeting.
§ 05
Required inspections
Scheduling and sequence
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 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.
§ 06
Frequently asked
Common questions about unincorporated Napa County permits
01 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.
02 How much does a building permit cost in unincorporated Napa County, CA? ▸
Building permit fees in unincorporated Napa County, CA are set by the local building department and vary by project type and valuation. 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..
03 How do I apply for a building permit in unincorporated Napa County, CA? ▸
To apply for a building permit in unincorporated Napa County, CA, follow these steps: 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.
04 How long does it take to get a building permit in unincorporated Napa County, CA? ▸
Building permit processing times in unincorporated Napa County, CA typically run 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.. Timelines can vary based on project complexity and current department workload.
05 What work is exempt from building permits in unincorporated Napa County, CA? ▸
Not all construction work requires a permit 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. When in doubt, confirm with the local building department before starting work.
06 How do I schedule a building inspection in unincorporated Napa County, CA? ▸
Once your permit is issued and work reaches an inspection milestone, you can schedule a building inspection in unincorporated Napa County, CA 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..
last verified April 2026
source Napa County Planning, Building & Environmental Services, Building Division ↗
entry id permits/california/napa/unincorporated
Educational reference. Permit rules and fees change — confirm current requirements directly with Napa County Planning, Building & Environmental Services, Building Division before applying. Jaspector is not legal advice.