Island County, WA Property Tax: $3,765/yr (2026)
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The effective property tax rate in Island County is 0.70% of assessed home value. On a home at the county median value of $535,300, that works out to about $3,747 per year, or $312 per month. Island County is located in northwestern Washington, and is home to approximately 86,747 residents.
About Island County
Island County covers approximately 208.5 square miles in Washington. The county is home to about 86,747 residents living in roughly 42,398 housing units, of which 62.6% are owner-occupied. The median household income is $88,358, and the median home was built in 1990.
Island County borders Jefferson County, Kitsap County, San Juan County, Skagit County, Snohomish County — useful comparisons if you're considering nearby areas with potentially different tax rates.
How Property Taxes Work in Washington
Property taxes in Washington are administered at the county level. Each county sets a millage rate applied to the assessed value of real property — the effective rate above accounts for any partial assessments and exemptions already built into the local tax base. Assessed value can differ meaningfully from current market value depending on how often the county reassesses and what fraction of market value it uses.
Most counties in Washington offer exemptions that reduce the taxable assessed value: homestead exemptions for primary residences, senior exemptions, disability exemptions, and veteran exemptions are common. These reduce your effective rate below the county-wide average shown here. Contact the Island County Assessor's office to learn which exemptions apply to your property and when to file.
Island County vs. Neighboring Counties
| Location | Eff. Rate | Median Home | Annual Tax |
|---|---|---|---|
| Island County, WA | 0.70% | $535,300 | $3,747 |
| Washington state average | 0.76% | — | $4,068* |
| Jefferson County | 0.73% | $495,100 | $3,596 |
| Kitsap County | 0.80% | $505,700 | $4,030 |
| San Juan County | 0.57% | $726,500 | $4,131 |
| Skagit County | 0.82% | $486,200 | $4,008 |
| Snohomish County | 0.79% | $644,600 | $5,121 |
| US national average | 1.10% | $281,900 | $3,101 |
*State average annual tax computed at Island County's median home value of $535,300. Source: US Census ACS 2023 5-year estimates.
Frequently Asked Questions
How does Island County's property tax rate compare to the rest of Washington?
At 0.70%, Island County is lower than the Washington state average of 0.76%. On a home at the county median of $535,300, that means about $3,747 per year — versus $4,068 at the state average rate, a difference of $321 per year. Compared to the national average of 1.10%, Island County is below average.
What's a typical annual property tax bill in Island County?
For a home at the county median value of $535,300, the annual property tax in Island County is approximately $3,747 — or about $312 per month. For a home worth $802,950, expect around $5,621 per year. For a $1,070,600 home, approximately $7,494 per year. Use the calculator above to estimate taxes for any assessed value.
Where do I appeal a Island County property tax assessment?
Property assessment appeals in Island County are handled by the Island County Assessor's office. Most jurisdictions require filing within 30–90 days of receiving your assessment notice — confirm the specific deadline with the assessor's office before submitting, as deadlines and procedures vary by county. A successful appeal can reduce your assessed value and lower your tax bill for the current and future tax years.
What exemptions are available in Island County?
Washington counties commonly offer homestead exemptions for owner-occupied primary residences, senior citizen exemptions for qualifying homeowners aged 65 and older, exemptions for disabled residents, and veterans' exemptions. Each exemption reduces your assessed taxable value, which in turn reduces your effective tax rate below the county-wide 0.70% shown here. Contact the Island County Assessor's office to confirm which exemptions are available and the application deadlines.
Data sources: US Census Bureau ACS 2023 5-Year Estimates, US Census Gazetteer (2024), County Adjacency File