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Updated 2025 Tax Year

San Juan County
Property Tax Guide

Everything you need to know about property taxes in San Juan County, WA. Rates, due dates, exemptions, and how it affects your monthly payment.

10 Official Sources
8 min read
Quick Facts
Tax Rate
0.944% effective rate (varies by location and special districts)
1st Due
Apr 30
2nd Due
Oct 31
Exemptions
5+ Available
Section 1

How Property Tax Works

San Juan County's property tax system funds essential local services including schools, county operations, fire protection, emergency medical services, and infrastructure maintenance across the scenic San Juan Islands. Property taxes are the primary revenue source for local government operations, with collections supporting everything from sheriff services to library operations throughout the archipelago.

The effective property tax rate in San Juan County is approximately 0.944% for the 2025 levy year, though actual rates vary significantly by location within the county due to different combinations of special taxing districts. Properties in incorporated areas like Friday Harbor may have different rates than unincorporated island communities, depending on which fire districts, library districts, and other special assessments apply to each specific location. Property owners should verify their exact rate based on their property's specific taxing district combination.

Section 2

What Makes Up Your Tax Bill

ComponentRate RangeDescription
County General Fund~$2.50/$1,000Basic county services, administration, courts
County Roads~$1.80/$1,000Road maintenance and transportation
School Districts~$4.50-6.00/$1,000K-12 education funding
Fire Districts~$1.50-2.50/$1,000Fire protection and emergency services
Library District~$0.50/$1,000San Juan Island Library District
State Levies~$2.70/$1,000State school funding and services
Total Effective Rate~$9.44/$1,000Varies by specific taxing districts

Rates shown are for levy year 2025 and represent typical ranges. Actual rates vary by property location and applicable special districts. The combined rate of approximately 0.944% applies to assessed value, not market value.

Section 3

When Are Property Taxes Due?

For the 2025/2026 tax year in San Juan County, property taxes are due in two installments:

First Installment
Apr 30
Delinquent after Dec 10
Second Installment
Oct 31
Delinquent after Apr 10
Pro tip: If you pay through mortgage escrow, your lender splits these payments across your monthly mortgage. If you pay directly, set calendar reminders to avoid late penalties.
Section 4

Supplemental Tax Bills

Supplemental taxes in San Juan County are triggered by ownership changes, new construction, or major property improvements that increase assessed value during the tax year. When these events occur, the county assessor calculates additional taxes owed on the increased assessed value for the remaining portion of the current tax year.

For example, if a property's assessed value increases from $400,000 to $500,000 due to completed construction in January, the owner would owe supplemental taxes on the additional $100,000 of assessed value for the full remaining tax year. The supplemental bill would be calculated as: $100,000 × 0.00944 = $944 in additional taxes, typically billed separately from regular property tax installments and due within 30 days of the supplemental assessment notice.

Example Calculation

Example 1: $300,000 Home

  • Assessed Value: $300,000
  • Senior/Disabled Exemption Applied: -$0 (if no application filed)
  • Net Taxable Value: $300,000
  • Annual Tax: $300,000 × 0.00944 = $2,832
  • Monthly Escrow: $236

Example 2: $600,000 Home with Senior Exemption

  • Assessed Value: $600,000
  • Senior/Disabled Exemption Applied: -$60,000 (requires application)
  • Net Taxable Value: $540,000
  • Annual Tax: $540,000 × 0.00944 = $5,098
  • Monthly Escrow: $425

Example 3: $1,000,000 Home

  • Assessed Value: $1,000,000
  • Tax Credits Applied: -$0 (most credits are income-limited)
  • Net Taxable Value: $1,000,000
  • Annual Tax: $1,000,000 × 0.00944 = $9,440
  • Monthly Escrow: $787

Note: All tax credits require application and income/age qualification. Credits reduce the tax bill, not the assessed value.

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Section 5

Escrow & Property Taxes

Most mortgage lenders in San Juan County require property tax escrow accounts, collecting monthly payments equal to 1/12th of the annual tax bill plus a small cushion. Since San Juan County operates on a semi-annual payment schedule with due dates of April 30 and October 31, lenders typically make payments directly to the county treasurer on these dates.

Property owners should verify their escrow payments annually when tax bills are issued, as assessment changes or rate adjustments can create escrow shortages or surpluses. Lenders are required to provide annual escrow analysis statements showing payment history and any necessary adjustments. If you pay taxes directly without escrow, you can pay the full amount by April 30 or split payments with half due April 30 and half due October 31 without penalty.

How HonestCasa Helps
  • Understand whether your escrow is set correctly
  • See how rising taxes will change your monthly payment
  • Plan ahead instead of being surprised by "shortage" letters
Section 6

Frequently Asked Questions

Q: When are property taxes due in San Juan County? A: For tax year 2025, the first half is due April 30, 2026, and the second half is due October 31, 2026. You can pay the full amount by April 30 or split the payments without penalty.

Q: What tax credits are available and do they require application? A: The main credits include the Senior Citizens & Disabled Persons Tax Relief Program and Tax Deferral Program. Both require annual application and have income/asset limits. These are tax credits that reduce your tax bill, not exemptions that reduce assessed value.

Q: How does the Senior/Disabled tax credit work? A: This program can exempt up to $60,000 of assessed value from taxation for qualifying applicants. It requires annual application with income verification and has strict eligibility requirements including age (61+) or disability status.

Q: When do I need to apply for tax credits? A: Applications for senior/disabled credits must typically be filed by December 31 of the assessment year. Contact the San Juan County Assessor's office for specific deadlines and application forms.

Q: How often are properties reassessed? A: Washington State requires annual assessment updates, but San Juan County conducts comprehensive revaluations on a rotating cycle. Market value changes are reflected annually based on sales data and market trends.

Q: What are the penalties for late payment? A: Interest and penalties accrue on unpaid taxes, typically starting at 1% per month. After three years of non-payment, the property may be subject to tax foreclosure proceedings.

Q: Can I pay property taxes online? A: Yes, San Juan County offers online payment options through their official website. You can also pay by mail, phone, or in person at the Treasurer's office in Friday Harbor.

Q: Why do tax rates vary within San Juan County? A: Different areas are served by different combinations of fire districts, library districts, and other special purpose districts. Your specific tax rate depends on which services your property location receives.

Q: How do I appeal my property assessment? A: Assessment appeals must be filed with the San Juan County Board of Equalization, typically by July 1 following the assessment year. Contact the Assessor's office for appeal forms and procedures.

Q: Are there any exemptions for new construction? A: Washington State offers some limited exemptions for certain types of new construction or improvements, but these require specific applications and have strict qualification requirements. Contact the Assessor's office for details on available programs.

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