Napa County Property Tax Appeal Guide
In Napa County, file your appeal by September 15, 2026 at Napa County Assessor's online portal.
| Deadline | Regular assessment appeals must be filed during one of two filing periods, set per county: July 2 through September 15 in counties where the assessor mailed an annual notice of assessed value to every assessee with real property on the local roll by August 1; otherwise July 2 through November 30. A separate 60-day clock applies to supplemental and escape assessments — an application must be filed within 60 days of the mailing/postmark date of the assessment notice or the tax bill, whichever is later (Rev. & Tax. Code §1605). A Proposition 8 decline-in-value reduction is sought during the regular July 2 period using the same Form BOE-305-AH. Confirm the exact county filing period on the county clerk of the board's site or the BOE annual filing-period letter to assessors. |
|---|---|
| Lien date | January 1, 2026 |
| Appeal body | Assessment Appeals Board (AAB) |
| Assessor / district | Napa County Assessor |
| Online portal | File online |
How to File a Appeal in Napa County
- Gather your assessment notice — it lists your account number and any access code
- File online through Napa County Assessor's portal or by mail
- State your grounds and submit evidence (comparable sales, a licensed appraisal, or photos of defects)
- Request an informal review to try to settle before a formal AAB hearing