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Updated 2025 Tax Year

Mason County
Property Tax Guide

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

6 Official Sources
8 min read
Quick Facts
Tax Rate
0.911% effective rate for 2025 (varies by taxing districts and location within county)
1st Due
Apr 30
2nd Due
Oct 31
Exemptions
5+ Available
Section 1

How Property Tax Works

Mason County, Washington operates under the state's property tax system, where property taxes fund essential local services including schools, roads, emergency services, and county operations. The county's effective property tax rate for levy year 2025 is approximately 0.911% (or $9.11 per $1,000 of assessed value), though this represents a combined rate that includes various local levies and special district assessments.

Property tax rates in Mason County vary significantly by location within the county due to different combinations of special taxing districts, including school districts, fire districts, library districts, and other local improvement districts. Your specific tax rate depends on which taxing districts serve your property location. The county assessor determines property values annually, and taxes are calculated by applying the combined rate of all applicable taxing districts to your property's assessed value.

Section 2

What Makes Up Your Tax Bill

ComponentApproximate RateDescription
County General Fund~$2.50/$1,000Basic county services, administration
County Roads~$1.80/$1,000Road maintenance and improvements
School Districts~$4.00-6.00/$1,000Varies by school district (North Mason, Shelton, etc.)
Fire/EMS Districts~$0.50-1.50/$1,000Fire protection and emergency services
Library Districts~$0.30-0.50/$1,000Public library services
Port Districts~$0.20-0.40/$1,000Where applicable
Special AssessmentsVariesDrainage, utilities, local improvements

Rates shown are for levy year 2025 and vary by specific location within Mason County. The combined rate of all applicable districts determines your total property tax rate. Contact the Mason County Assessor for your property's exact taxing district combination.

Section 3

When Are Property Taxes Due?

For the 2025/2026 tax year in Mason 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 property taxes in Mason County are triggered by specific events that change a property's assessed value during the tax year. The most common triggers include ownership transfers (sales), new construction completion, major renovations, or additions that increase the property's value.

When a supplemental assessment occurs, the county calculates the difference between the old and new assessed values, then applies the current tax rate to determine additional taxes owed. For example, if you purchase a home in March that was previously assessed at $250,000 but sells for $400,000, a supplemental assessment will be issued for the increased value, prorated for the remaining months of the tax year. The supplemental tax bill is typically mailed 30-60 days after the triggering event and becomes due immediately upon receipt.

Example Calculation

Example 1: $300,000 Home

  • Assessed Value: $300,000
  • Senior Citizen Credit Applied: -$0 (if qualified and applied for)
  • Net Taxable Value: $300,000
  • Tax Rate: 0.911%
  • Annual Tax: $2,733
  • Monthly (if escrowed): $228

Example 2: $600,000 Home

  • Assessed Value: $600,000
  • Homestead Credit Applied: Assessment increase limited to 10% annually (if applied for)
  • Net Taxable Value: $600,000
  • Tax Rate: 0.911%
  • Annual Tax: $5,466
  • Monthly (if escrowed): $456

Example 3: $1,000,000 Home

  • Assessed Value: $1,000,000
  • Credits Applied: Varies by eligibility and application
  • Net Taxable Value: $1,000,000
  • Tax Rate: 0.911%
  • Annual Tax: $9,110
  • Monthly (if escrowed): $759

Note: All tax credits require separate application and approval. Rates may vary based on your property's specific taxing districts.

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Section 5

Escrow & Property Taxes

Most mortgage lenders in Mason County require borrowers to maintain an escrow account for property tax payments, especially when the loan-to-value ratio exceeds 80%. Your lender collects monthly escrow payments along with your mortgage payment, depositing these funds into a dedicated account. The lender then pays your property taxes directly to Mason County when they become due.

Property taxes in Mason County are typically due in two installments: the first half due April 30th and the second half due October 31st of each year. Lenders usually pay these installments on your behalf before the due dates to avoid penalty charges. You'll receive an annual escrow analysis from your lender showing the previous year's tax payments and any adjustments needed for the coming year. It's important to review your tax statements even when using escrow to ensure accuracy and to monitor any changes in assessed value or tax rates that might affect your escrow requirements.

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 Mason County for fiscal year 2025? A: Property taxes are due in two installments: first half by April 30, 2025, and second half by October 31, 2025. Taxes become delinquent if not paid by these dates.

Q: What tax credits are available and do they require application? A: Mason County offers several tax credits that REQUIRE APPLICATION, including Senior Citizen/Disabled Person Credit (income-qualified), Veterans Disability Credit, and Homestead Credit. None are automatic - you must apply annually by December 31st for the following tax year.

Q: How does the Homestead Credit work? A: The Homestead Credit limits annual assessment increases to 10% for qualifying owner-occupied homes, but requires annual application. It doesn't reduce market value, only caps how much your assessed value can increase year-over-year.

Q: How often are properties reassessed in Mason County? A: All properties are physically inspected and valued annually. The county assessor updates assessments based on market conditions, with new values taking effect January 1st of each tax year.

Q: What are the penalties for late property tax payments? A: Interest accrues at 1% per month on unpaid taxes after the due date. Additional penalties may apply, and properties may eventually face tax foreclosure proceedings for continued non-payment.

Q: Can I pay my property taxes online? A: Yes, Mason County offers online payment options through their official website. You can also pay by mail, in person at the Treasurer's office, or set up automatic payments.

Q: How do special district taxes affect my bill? A: Your location determines which special districts (fire, school, library, etc.) serve your property. Each district sets its own levy rate, and all applicable rates are combined to calculate your total tax bill.

Q: How do I appeal my property assessment? A: Assessment appeals must be filed with the Mason County Board of Equalization by July 1st following the assessment year. You can appeal based on valuation errors, unequal treatment, or incorrect property characteristics.

Q: Who qualifies for the Senior Citizen tax credit? A: Applicants must be 61+ years old (or disabled/veteran), occupy the property as their primary residence, and meet income limits set by the state. Applications must be submitted annually by December 31st.

Q: What exemptions are available for new construction or improvements? A: Mason County may offer exemptions for certain physical improvements or new construction projects. Currently, there are limited participants in available exemption programs, and eligibility requirements are very specific.

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