Property tax in Whatcom County, Washington
In Whatcom County, the property tax bill comes from the Whatcom County Treasurer's Office. The 2026 bill is paid in 2 installments, and the next one is due October 31, 2026. You can look up and pay the bill on the county's own payment page. Taken from Whatcom County's own pages, checked September 23, 2026.
The median property tax bill in Whatcom County, Washington is $4,087 a year, which is about 0.7% of the county's median home value of $585,800. That effective rate is lower than the typical Washington county (0.73%) and lower than the national median (0.81%). These are American Community Survey 5-year estimates (2024); your own bill depends on your home's assessed value and any exemptions.
Who sends the property tax bill in Whatcom County, and how do you pay it?
The bill comes from the Whatcom County Treasurer's Office. The value it is based on is set by a separate office, the Whatcom County Assessor's Office, which is who to ask if the value looks wrong. For how to look up and pay the bill, go to the county's own payment information.
Washington collects in the same calendar year it names: the 2026 bill is paid April 30 and October 31, 2026. The treasurer also collects taxes for the cities, port, school, fire and other districts, so a single county bill covers them all. Mailed payments go to Whatcom County Treasurer, PO Box 34873, Seattle, WA 98124-1873; the office is in the Courthouse at 311 Grand Ave, Suite 104, Bellingham, with payment drop boxes at each entrance. Online, phone and card payments carry a convenience fee.
When are property taxes due in Whatcom County?
For the 2026 bill, Whatcom County splits the bill into 2 payments, the first due April 30, 2026 and the last October 31, 2026. The next one due is the second half, on October 31, 2026. Late taxes are charged interest monthly from the date of delinquency until paid. On homes and other residential parcels with four or fewer units the rate is 9% a year (0.75% a month) with no penalties. On all other property it is 12% a year (1% a month) plus a 3% penalty on June 1 and an 8% penalty on December 1. If the first half is paid after April 30, interest (and any penalty) is charged on the full year's tax, not just the first half. The treasurer's interest and penalty page still lists 1% a month and the penalties for every parcel; state law changed that for 2023 and later tax years.
| Payment | Due | Note |
|---|---|---|
| First half (or full amount) | April 30, 2026 (passed) | Already past for the 2026 cycle. A bill under $50 is due in full by April 30. |
| Second half | October 31, 2026 | October 31, 2026 is a Saturday. The county's pages do not state a weekend rule, but state law (RCW 1.12.070) says a tax payment due on a Saturday, Sunday or legal holiday is on time if made the next business day, so a payment made Monday, November 2, 2026 is on time. A mailed payment must carry an official postmark dated on or before the due date. |
From Whatcom County's published schedule, checked September 23, 2026. If a date falls on a weekend or holiday, the county's own rules on the next business day apply.
Estimate the property tax on a home in Whatcom County
Enter a home's market value for a ballpark at Whatcom County's average effective rate of 0.7% (Census). The real bill depends on the home's assessed value, the millage where it sits and any exemptions.
Estimated property tax: $4,101 / year
Property tax in Whatcom County at a glance
| Measure | Value |
|---|---|
| Median annual property tax | $4,087 |
| Median home value | $585,800 |
| Effective tax rate | 0.7% |
| Typical Washington county rate | 0.73% |
| National median county rate | 0.81% |
Effective rate = median real estate taxes paid divided by median home value. Source: U.S. Census Bureau, American Community Survey 5-year estimates.
How does Whatcom County compare in Washington?
Among Washington's 39 counties, Whatcom County has the 28th highest effective property-tax rate: 27 rank higher and 11 rank lower. That is on the lower side for Washington. Nationally, it ranks 1907th of 3135 US counties by effective rate. See every Washington county ranked.
How much do homeowners in Whatcom County actually pay?
The median is only the middle bill. Across Whatcom County's 59,904 owner-occupied homes, 67.1% pay $3,000 or more a year in property tax, 79.6% pay at least $2,000, and 6.2% pay under $800. Another 3.9% report paying no property tax at all, which usually means an exemption covers the whole bill.
| Annual bill | Homes | Share |
|---|---|---|
| Under $800 | 3,734 | 6.2% |
| $800 to $1,499 | 3,232 | 5.4% |
| $1,500 to $1,999 | 2,882 | 4.8% |
| $2,000 to $2,999 | 7,491 | 12.5% |
| $3,000 or more | 40,201 | 67.1% |
| No property tax paid | 2,364 | 3.9% |
Owners with a mortgage pay a median of $4,135 and owners without one pay $3,987. That is within 10% either way, so in Whatcom County paying off the house does not go with a noticeably different bill. Census table B25103.
How does the Whatcom County property tax bill compare with local incomes?
The median property tax bill of $4,087 is about 3.9% of the median income of Whatcom County homeowner households, $104,932 a year. That compares two middles, so a retiree in a long-held home can pay a far larger share. 63.7% of Whatcom County's occupied homes are lived in by their owners; renters pay property tax too, just folded into rent.
Have property taxes gone up in Whatcom County?
Yes. The median bill went from $2,836 in 2015-2019 to $4,087 in 2020-2024, a 44.1% rise. Over the same span the median home value moved 69.5%, from $345,700 to $585,800. Bills rose more slowly than values, which is what assessment caps and falling millage rates do: the county is taxing a smaller share of each home's worth.
Two Census ACS 5-year periods with no survey years in common, in each period's own dollars. A change counts only if it exceeds the combined 90% margin of error.
Property tax in counties next to Whatcom County
Whatcom County borders 3 counties.
| County | Effective rate | Median bill | Median home value |
|---|---|---|---|
| Skagit County, WA | 0.79% | $4,308 | $545,100 |
| Okanogan County, WA | 0.76% | $2,281 | $299,800 |
| Whatcom County, WA (this county) | 0.7% | $4,087 | $585,800 |
| San Juan County, WA | 0.53% | $4,253 | $799,200 |
How is a home assessed in Whatcom County?
Washington assesses homes at 100% of market value in every county, Whatcom County included. How Washington assesses and reappraises homes.
Is there a homestead exemption in Whatcom County?
No. Washington has no general homestead exemption; the broad protection is the 1% limit on how much a taxing district's regular levy can grow each year without voter approval. That is the Washington rule, and it applies in Whatcom County. Washington's exemptions and relief programs in full.
Whatcom County does not add relief programs of its own beyond the Washington ones (checked September 23, 2026).
How to appeal your Whatcom County property assessment
In Whatcom County you appeal to the Whatcom County Board of Equalization. The deadline: State law sets the deadline: by July 1 of the assessment year or within 30 days of the date the change of value notice was mailed, whichever is later (a county may allow up to 60 days). Whatcom County mails change of value notices in the fall; the 2025 notices, which set values for 2026 taxes, were mailed September 26, 2025. A further appeal goes to the State Board of Tax Appeals. How to file. Checked September 23, 2026 against state law, because Whatcom County does not restate them on its own pages.
How Washington's appeal process works, including the next level if the first one turns you down.
Washington rules from primary state sources, reviewed September 7, 2026; sources on the Washington page.
Work out your own numbers
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How much house can I afford?
Your income, debts and down payment against the 28/36 rule lenders actually use, with Whatcom County's tax rate to hand.
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Mortgage calculator
Monthly payment with principal, interest, tax and insurance, plus what an extra payment saves you.
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Washington income tax
Brackets, standard deduction and what Washington actually taxes.
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Sales tax in Whatcom County
The other local tax: combined state and local rate for this county.
Sources
- Median real estate taxes paid and median home value for Whatcom County, Washington: U.S. Census Bureau, American Community Survey 5-year estimates (2020-2024), tables B25103, B25077, B25102, B25119 and B25003; the five-year comparison uses the 2015-2019 estimates. Neighboring counties: Census county adjacency file.