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Updated 2025 Tax Year

Washington County
Property Tax Guide

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

10 Official Sources
8 min read
Quick Facts
Tax Rate
15-25 mills per $1,000 assessed value (varies by municipality within county)
Exemptions
6+ Available
Section 1

How Property Tax Works

Washington County, Wisconsin operates under the state's property tax system, which serves as the primary funding mechanism for local government services including schools, municipal services, county operations, and special districts. Property taxes in Washington County fund essential services such as education, public safety, road maintenance, parks and recreation, and various county-administered programs. The tax system is administered at the municipal level, with each city, town, and village within the county collecting taxes for their respective jurisdictions.

The effective property tax rate in Washington County varies significantly by municipality and can range from approximately 15 to 25 mills per $1,000 of assessed value, depending on your specific location within the county. This variation occurs because property taxes include levies from multiple overlapping jurisdictions: the municipality (city/town/village), school district, county, technical college district, and various special districts such as fire protection, sanitary districts, or tax incremental financing (TIF) districts. Each property's total tax bill represents the combined levies of all applicable taxing authorities, making location a critical factor in determining your actual tax burden.

Section 2

What Makes Up Your Tax Bill

The following table shows typical property tax components for Washington County properties for the 2024 levy year (taxes payable in 2025):

ComponentApproximate Rate (per $1,000)Description
County Levy$3.50 - $4.50County operations, social services, courts
Municipal Levy$2.00 - $6.00City/town/village services, varies by municipality
School District$8.00 - $12.00K-12 education, varies significantly by district
Technical College$0.50 - $1.00Wisconsin Technical College System
Special Districts$0.50 - $3.00Fire protection, sanitary, library, other local districts
Total Estimated Range$14.50 - $26.50Combined mill rate varies by property location

Note: These rates are estimates for the 2024 levy year and actual rates vary considerably based on your specific municipality and special taxing districts. Properties in the same county can have significantly different total rates depending on which school district, municipality, and special districts serve that location. Official mill rates are published annually by each municipality and are available through your local treasurer's office.

Section 3

When Are Property Taxes Due?

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

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 Washington County are additional property tax assessments that occur outside the regular annual tax cycle. These are primarily triggered by changes in property ownership, new construction completion, or property improvements that were not included in the regular January 1st assessment date. When you purchase a home or complete significant improvements after the assessment date, the county assessor may issue a supplemental assessment to capture the change in property value.

Supplemental taxes are calculated using the same mill rate applied to your regular property tax bill, but only for the portion of the tax year remaining after the triggering event. For example, if you purchase a home in Washington County in July that results in a $50,000 increase in assessed value, and your combined mill rate is 20 per $1,000, your supplemental tax would be approximately $1,000 × (6 months remaining ÷ 12 months) = $500. These supplemental bills are typically issued within 60-90 days of the triggering event and have separate due dates from your regular property tax installments.

Example Calculation

The following examples show estimated annual property taxes for Washington County properties at different values, assuming a moderate mill rate of 20 per $1,000 and application of available tax credits:

Example 1: $300,000 Property

  • Assessed Value: $300,000
  • Homestead Credit Applied: -$1,000 (estimated, requires application)
  • Lottery Credit Applied: -$150 (varies annually)
  • Net Taxable Value: $298,850
  • Annual Tax (20/$1,000): $5,977
  • Monthly Escrow: $498

Example 2: $600,000 Property

  • Assessed Value: $600,000
  • Homestead Credit Applied: -$1,200 (estimated, requires application)
  • Lottery Credit Applied: -$150 (varies annually)
  • Net Taxable Value: $598,650
  • Annual Tax (20/$1,000): $11,973
  • Monthly Escrow: $998

Example 3: $1,000,000 Property

  • Assessed Value: $1,000,000
  • Homestead Credit Applied: -$1,500 (estimated, requires application)
  • Lottery Credit Applied: -$150 (varies annually)
  • Net Taxable Value: $998,350
  • Annual Tax (20/$1,000): $19,967
  • Monthly Escrow: $1,664

Note: These examples use estimated credit amounts. Actual homestead and lottery credits vary annually and require proper application. Credits are not automatic and must be claimed through your municipality.

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Section 5

Escrow & Property Taxes

Most mortgage lenders in Washington County require borrowers to establish an escrow account for property tax payments, particularly when the loan-to-value ratio exceeds 80%. Your lender collects monthly escrow payments as part of your mortgage payment, typically calculated as your annual tax bill divided by 12 months, plus a cushion of 1-2 months. The lender then pays your property taxes directly to the appropriate municipality on your behalf when the January 31st and July 31st due dates arrive.

Washington County property taxes are paid in two installments: the first installment is due January 31st, and the second installment is due July 31st each year. Your lender will receive tax bills directly from your municipality and should pay these automatically from your escrow account. However, it's important to verify that payments are made on time, as you remain ultimately responsible for ensuring taxes are paid. You can verify payments online through your municipality's website or by contacting your local treasurer's office. If your escrow account has insufficient funds, you may receive a shortage notice requiring additional payments, and if taxes go unpaid, the property can be subject to tax sale proceedings regardless of your mortgage status.

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 Washington County property taxes due for the current fiscal year? A: Property taxes are due in two installments each year: January 31st for the first installment and July 31st for the second installment. You can pay the full year amount by January 31st or split into these two payments.

Q: What tax credits are available and do they apply automatically? A: The primary credits available are the Homestead Credit and Lottery Credit. Neither is automatic - both require application through your municipality. The Homestead Credit helps limit assessment increases for qualified homeowners, while the Lottery Credit provides a small annual reduction in your tax bill.

Q: How does the Homestead Credit work and who qualifies? A: The Homestead Credit limits the annual increase in your home's assessed value for tax purposes, not the actual market value. You must be 18 or older, own and occupy the property as your primary residence, and file an application with your municipality. This credit caps assessment growth rather than reducing your home's assessed value.

Q: How often are properties reassessed in Washington County? A: Wisconsin law requires properties to be assessed annually as of January 1st. However, municipalities may conduct full revaluations every few years. If you disagree with your assessment, you can appeal through your local Board of Review, typically meeting in May.

Q: What are the penalties for late property tax payments? A: Late payments incur interest charges that accrue monthly. If taxes remain unpaid, the property may be subject to tax sale proceedings. Contact your municipal treasurer immediately if you cannot make payments by the due dates.

Q: Can I pay my property taxes online? A: Most Washington County municipalities offer online payment options through their websites or third-party services. Check with your specific city, town, or village treasurer's office for available online payment methods and any associated convenience fees.

Q: Why do property tax rates vary within Washington County? A: Tax rates vary because each property pays taxes to multiple overlapping jurisdictions: your municipality, school district, county, technical college, and special districts. Different combinations of these taxing authorities result in different total mill rates throughout the county.

Q: What should I do if I receive a supplemental tax bill? A: Supplemental tax bills are typically issued for new construction, property improvements, or ownership changes. Review the bill for accuracy and pay by the specified due date. Contact your municipal assessor if you believe the supplemental assessment is incorrect.

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