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Updated 2025 Tax Year

Iowa County
Property Tax Guide

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

10 Official Sources
8 min read
Quick Facts
Tax Rate
10.533 mills (1.05%) for 2025, varies by school district and municipality
Exemptions
5+ Available
Section 1

How Property Tax Works

Iowa County, Wisconsin operates under a property tax system that funds essential local services including schools, county government, municipal services, and special districts. Property taxes are the primary revenue source for local governments in the county, supporting everything from road maintenance and public safety to library services and parks.

The effective property tax rate in Iowa County for 2025 is 10.533 mills (approximately 1.05%), though actual rates vary significantly by location within the county due to different combinations of school districts, municipalities, and special taxing districts. Property taxes are assessed annually based on the assessed value of real estate as of January 1st, with tax bills reflecting the levy year 2025. Property owners should note that their specific tax rate depends on which taxing jurisdictions serve their property location.

Section 2

What Makes Up Your Tax Bill

ComponentRate (Mills)Description
Total Mill Rate10.533Combined rate for all taxing jurisdictions (FY 2025)
County LevyVariesIowa County government services
School DistrictVariesLocal school district operations and debt service
MunicipalVariesCity/town services (fire, police, roads)
Technical CollegeVariesSouthwest Wisconsin Technical College district
Special DistrictsVariesLibrary, sanitary, fire protection districts

Note: The 10.533 mill rate represents one specific combination of taxing districts within Iowa County. Your actual rate may differ based on your property's location and which school district, municipality, and special districts serve your area. Contact the Iowa County Assessor's office at (608) 935-0398 for your specific district combination.

Section 3

When Are Property Taxes Due?

For the 2025/2026 tax year in Iowa 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 Iowa County are typically triggered by new construction, property improvements, or changes in ownership that result in reassessment during the tax year. When improvements are completed or property changes hands, the assessor may issue a supplemental assessment reflecting the increased value for the portion of the tax year remaining.

Supplemental taxes are calculated by taking the difference between the new assessed value and the original assessed value, multiplying by the applicable mill rate, then prorating for the remaining months in the tax year. For example, if a $50,000 addition is completed in April, the supplemental tax would be calculated on that $50,000 increase for the remaining 9 months of the tax year at the property's applicable mill rate.

Example Calculation

Example 1: $300,000 Property

  • Assessed Value: $300,000
  • Less: Homestead Credit (if applied): $0 (varies by income/age)
  • Net Taxable Value: $300,000
  • Annual Tax (10.533 mills): $3,160
  • Monthly Payment: $263

Example 2: $600,000 Property

  • Assessed Value: $600,000
  • Less: Homestead Credit (if applied): $0 (varies by income/age)
  • Net Taxable Value: $600,000
  • Annual Tax (10.533 mills): $6,320
  • Monthly Payment: $527

Example 3: $1,000,000 Property

  • Assessed Value: $1,000,000
  • Less: Senior/Veterans Credits (if applied): $0 (varies)
  • Net Taxable Value: $1,000,000
  • Annual Tax (10.533 mills): $10,533
  • Monthly Payment: $878

Note: Tax credits require separate applications and eligibility verification. Contact Iowa County for available programs.

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Section 5

Escrow & Property Taxes

Most mortgage lenders require property tax escrow accounts for Iowa County properties. Lenders collect monthly payments equal to 1/12 of your annual property tax bill plus insurance premiums. These funds are held in escrow and used to pay your tax bills when due.

Tax payments are made in two installments: first half due September 1st and second half due July 31st of the following year. Lenders typically pay these on your behalf before the due dates to avoid penalties. Property owners should verify that their lender has received and processed tax bills correctly, as you remain ultimately responsible for payment even when using escrow. You can verify payments through the Iowa County Treasurer's office online portal or by calling (608) 935-0399.

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 Iowa County property taxes due for 2025? A: First half taxes are due September 1, 2025, and second half taxes are due July 31, 2026.

Q: What tax credits are available and do they require applications? A: Wisconsin offers various tax credits including Homestead Credit, Veterans Credit, and Senior Citizens Credit. All credits require separate applications and are NOT automatic. Contact the Iowa County Assessor at (608) 935-0398 for applications and deadlines.

Q: How does the Homestead Credit work? A: The Homestead Credit limits annual assessment increases rather than reducing market value. It caps assessment growth and requires annual application. This is a tax credit that reduces your tax bill, not an exemption that reduces assessed value.

Q: How often are properties reassessed in Iowa County? A: Wisconsin law requires municipalities to assess at least once every five years, though many assess annually. Iowa County typically follows state guidelines with periodic revaluation cycles.

Q: What are the penalties for late payment? A: Interest and penalties accrue on unpaid taxes after the due dates. Contact the Iowa County Treasurer at (608) 935-0399 for current penalty rates and payment options.

Q: Can I pay my property taxes online? A: Yes, Iowa County offers online payment options. Visit the county website or contact the Treasurer's office for secure payment portal access and accepted payment methods.

Q: How do special district taxes work? A: Special districts (library, fire, sanitary) levy additional taxes for specific services. Your total rate includes all districts serving your property location. The 10.533 mill rate includes these district levies.

Q: How do I appeal my property assessment? A: Assessment appeals must be filed with the local Board of Review, typically meeting in May. Contact the Iowa County Assessor's office for appeal procedures, deadlines, and required documentation.

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