Napa County Property Tax
The average property-tax rate in Napa County is about 1.1% of assessed value (Board of Equalization county average, 2024-25) — the 1% Proposition 13 base levy plus each area's voter-approved debt. That's close to the statewide average of about 1.11%, making it the 27th-highest of California's 58 counties (the 32nd-lowest). On a $500,000 assessed value that's roughly $5,520 a year. Estimate your own bill below, or jump to due dates & where to pay or assessed value by city.
Napa County property tax: the short answers
- Due dates (2026–27). First installment due Sunday, November 1, 2026, pay by 5 p.m. Thursday, December 10, 2026; second due Monday, February 1, 2027, pay by 5 p.m. Monday, April 12, 2027 (April 10 is a Saturday). Napa County has not published a 2026–27 mailing date; bills must go out by November 1 (§2610.5).
- Where to pay. Online at www.napacounty.gov/1227/Treasurer---Tax-Collector (search by parcel number or address). No bill yet? Call 707-253-4311 for a duplicate; a missing bill does not excuse a late payment (§2610.5).
- Typical bill. The county's average single-family home is assessed at about $849,419 (Board of Equalization, 2025), which at the 1.104% county average comes to about $9,378 a year before Mello-Roos and direct charges. A new buyer pays on the purchase price instead.
- Your rate depends on where you are. Across Napa County's 97 Tax Rate Areas the ad-valorem rate runs from 1.05% to 1.13% (2025/2026 rate book); see what is in your rate, or the rate by ZIP code.
- Look up a parcel. Napa County Assessor for assessed value and exemptions; the tax collector's portal above for the bill itself.
How Napa County property tax is calculated
California taxes property under Proposition 13: your assessed value is generally set when you buy, then rises no more than 2% a year until the property changes hands or is newly built. The annual bill is that assessed value times the ad-valorem rate — the 1% base plus voter-approved bonds — which is why Napa County's average works out to about 1.1%. Because the bonds differ by Tax Rate Area, two homes in the same county can pay slightly different rates.
What's on a property tax bill
Ad-valorem tax (1% base + voter-approved debt) · Mello-Roos special taxes, where a parcel is in a Community Facilities District (how long they last) · fixed direct assessments (lighting, sewer, etc.). Only the first is value-based; the 1.1% rate covers that part.
Learn the rules behind the rate: how California property tax is calculated, Proposition 13, Mello-Roos, and what triggers a reassessment.
Want your exact rate, not the county average? See what's in your Napa County property tax → — browse by city and Tax Rate Area, or look up your parcel, for the itemized ad-valorem breakdown.
The 1.1% figure is a county average; the actual ad-valorem rate differs by Tax Rate Area. See the Napa County property tax rate by ZIP code → for the typical rate, home value, and bill in each ZIP.
Some Napa County communities also pay a Mello-Roos special tax — see the Napa County CFD district list → with each district's bond debt and delinquency.
Napa County property tax by the numbers
How much is property tax in Napa County? For an existing owner the average single-family home is assessed near $849,419, so at the county's 1.104% average rate (Board of Equalization county average, 2024-25) the implied bill is about $9,378 a year (a mean across all existing owners, not a median). A new buyer is taxed on the purchase price instead — use the calculator above. The figures below are the county-level activity behind that rate.
Sources: California State Board of Equalization (assessors' workload tables, Table E1 single-family values, property-tax allocation), the California Debt and Investment Advisory Commission (Mello-Roos roster), the California FAIR Plan Association (policies in force by county) and CAL FIRE / OSFM fire hazard severity zones weighted by 2020 housing units. County aggregates only, no parcel or owner identities; counts are filings processed and can lag the event year. Verify with the Napa County Assessor before relying on them.
Due dates & where to pay
Napa County property taxes are paid in two installments: first due November 1 (delinquent after December 10) and second due February 1 (delinquent after April 10). A 10% penalty applies after each delinquency date, and a bill still unpaid on July 1 becomes tax-defaulted; after five years in default the county may sell it at auction (see the California tax sale calendar). Boats, aircraft and business equipment are billed separately on the unsecured roll, due in one payment by August 31. Pay or look up a parcel through the Napa County Treasurer-Tax Collector. Portal links, fees and missing-bill numbers for every county are on one look-up-and-pay page.
These deadlines are set by California state law (Revenue & Taxation Code §§ 2605, 2606, 2617 and 2701) and are the same in every county — this is general education, not a county-by-county check. If a delinquency date falls on a weekend or legal holiday, it moves to the next business day. Always confirm the exact dates and amounts on your own tax bill and your county tax collector's website. See the full California property tax due-date calendar for the dated 2026–27 schedule, penalties, and when bills are mailed.
Ways to lower your bill
- The $7,000 Homeowners' Exemption for owner-occupants (~$70/yr) — not the same as the homestead exemption, which protects home equity from creditors and changes no tax.
- Senior programs — Property Tax Postponement (62+, income-qualified; the state pays the bill at 5% simple interest) and a Proposition 19 base-year transfer (55+).
- A Proposition 8 decline-in-value review if the market drops below your assessed value.
- Appealing your assessment if it looks too high — the regular filing window in Napa County runs July 2 to November 30 (2026); only the assessed value can be appealed, not the rate or the flat charges.
Selling in Napa County: the transfer tax
A sale also pays a one-time documentary transfer tax of $1.10 per $1,000 of the price (net of any loan the buyer takes over) to the county (Revenue and Taxation Code §11911), $1,100 on a $1,000,000 sale. We have found no city transfer tax in Napa County (the 27 California cities whose codes we have read are mostly in the Bay Area and Los Angeles County), so the county rate is normally the whole tax. Estimate it for any sale with the California transfer tax calculator; the documentary transfer tax guide covers who pays and the exemptions.
Napa County assessed value by city
The size of the property-tax base in each of Napa County's 5 incorporated cities: the total assessed value of all property inside the city limits on the 2025 roll, how fast it is growing, and its share of the county's $58.3 billion total. Dividing by each city's population shows how much taxable property stands behind each resident: from $695k in St. Helena down to $200k in American Canyon. About 49.1% of the county's assessed value lies outside any city, in unincorporated areas.
| City | Assessed value (2025 roll) | 1-year change | Since 2013 | Share of county | Per resident |
|---|---|---|---|---|---|
| Napa | $18.2 billion | +4.8% | +97.9% | 31.3% | $238k |
| American Canyon | $4.56 billion | +2.3% | +104.1% | 7.8% | $200k |
| St. Helena | $3.61 billion | +4.1% | +86.1% | 6.2% | $695k |
| Calistoga | $1.91 billion | +11.3% | +170.7% | 3.3% | $386k |
| Yountville | $1.36 billion | -2.8% | +139.4% | 2.3% | $424k |
Assessed value = the whole city's roll (homes, businesses, land and state-assessed utility property together) as reported by the Board of Equalization (Table 11), a Proposition 13 basis — not a typical home value, a tax rate or a bill. Growth reflects reassessment on sale, new construction, the annual inflation factor (capped at 2%), Proposition 8 decline-in-value cuts and their restoration, disaster losses, and any change in city boundaries. Share of county uses the county's total assessed value (Table 10); the two tables' bases differ slightly. Per resident divides the city's roll by its July 1, 2025 Census population estimate (Population Estimates Program, Vintage 2025); a high figure means a lot of commercial, industrial or second-home value per inhabitant, not a high tax bill. Napa County does not publish its parcel roll in bulk, so the per-home figure on this page is the Board of Equalization's average single-family assessment (the “Typical bill” line above, about $9,378 a year) rather than a roll median — use the county rate and the calculator above for your own estimate.
Neighboring counties' property tax rates
Napa County averages about 1.1%. Of the 4 counties that border it, 0 average less, 4 more:
Frequently Asked Questions
What is the property tax rate in Napa County?
Napa County's average property tax rate is about 1.1% of assessed value (California Board of Equalization, 2024-25) — the 1% Proposition 13 base levy plus each area's voter-approved debt. That's close to the statewide average of about 1.11%. Your parcel's exact rate depends on its Tax Rate Area; Mello-Roos and fixed direct assessments, where they apply, are billed on top.
How much is property tax in Napa County?
Multiply your assessed value by about 1.1%. On a $500,000 assessed value that's roughly $5,520 a year. The county's average single-family assessed value is about $849,419 (Board of Equalization, 2025), which at the county's 1.104% average rate (BOE county average, 2024-25) works out to an implied bill near $9,378 a year for an existing owner. Under Proposition 13 your assessed value is generally what you paid when you bought, rising no more than 2% a year — use the calculator above for your own number.
When are Napa County property taxes due?
For 2026–27: the first installment is due Sunday, November 1, 2026 and must be paid by 5 p.m. Thursday, December 10, 2026; the second is due Monday, February 1, 2027 and must be paid by 5 p.m. Monday, April 12, 2027 (April 10 falls on a Saturday). Napa County had not published a 2026–27 mailing date when we last checked; every county must mail or e-mail the annual bill by November 1 (Revenue and Taxation Code §2610.5). The first installment is due November 1 and delinquent after December 10; the second is due February 1 and delinquent after April 10. A 10% penalty applies after each delinquency date. These deadlines are set by California state law (Revenue & Taxation Code §§2605–2606 and §§2617–2619) and are the same in every county; confirm the exact dates on your bill and the county tax collector's website.
How do I look up or pay my Napa County property tax?
Look up and pay on the Napa County Treasurer-Tax Collector's portal at www.napacounty.gov/1227/Treasurer---Tax-Collector — search by Assessor's Parcel Number (APN, printed on any prior bill) or, on most portals, by address; it shows both installments, penalties and payment history. The portal shows any e-check or card fee before you confirm. If your bill has not arrived, call 707-253-4311 for a duplicate — not receiving a bill does not excuse a late payment (Revenue and Taxation Code §2610.5). The county has not announced a 2026–27 mailing date; by law bills go out by November 1. Every county's portal, fees and missing-bill number are on one page: californiapropertytools.com/california-property-tax-lookup-and-pay/#napa.
How can I lower my Napa County property tax?
Claim the $7,000 Homeowners' Exemption if you occupy the home; check the senior Property Tax Postponement and, if you're 55+, a Proposition 19 base-year transfer; if the market has fallen below your assessed value, request a Proposition 8 decline-in-value review; and appeal your assessment if it looks too high.
Official Napa County offices
Look up your parcel, exact rate, and bill directly with the county:
- Napa County Assessor — assessed value, exemptions, and parcel records.
- Napa County Auditor-Controller — the tax-rate book and Tax Rate Areas.
- Napa County Treasurer-Tax Collector — pay your bill and look up amounts due.
- Napa County GIS / parcel data — maps and downloadable parcel layers.
Learn More
Rate source: California State Board of Equalization county-average property tax rate (2024-25) — total ad-valorem levies divided by net assessed value. This is a county average; your parcel's rate depends on its Tax Rate Area, and Mello-Roos or fixed direct assessments are extra. Educational estimate, not an official bill — confirm figures with the Napa County Assessor and Treasurer-Tax Collector.