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Updated 2025 Tax Year

Union County
Property Tax Guide

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

10 Official Sources
8 min read
Quick Facts
Tax Rate
$18.00 per $1,000 assessed value (base county rate, varies by district with additional levies)
1st Due
Sep 30
2nd Due
Mar 31
Exemptions
5+ Available
Section 1

How Property Tax Works

Union County, Iowa operates on a property tax system that funds essential local services including schools, county operations, emergency services, and infrastructure maintenance. Property taxes are the primary revenue source for these vital community services. For fiscal year 2025, Union County has a property tax rate of $18.00 per $1,000 of assessed valuation, though this represents just one component of the total tax burden property owners face.

The actual property tax rate varies significantly by location within Union County due to different combinations of special taxing districts. These districts include school districts, city levies, rural fire districts, and other local service areas. Property owners may see different total rates depending on which municipal boundaries, school districts, and special service areas their property falls within. The county assessor determines assessed values, while various taxing authorities set their individual levy rates that combine to create each property's total tax obligation.

Section 2

What Makes Up Your Tax Bill

ComponentRate per $1,000Description
County General$18.00Basic county services and operations (FY 2025)
School DistrictVariesLocal school district levy (varies by district)
City/MunicipalVariesCity services (applies only within city limits)
TownshipVariesTownship services for rural areas
Rural Fire DistrictVariesFire protection services
Emergency ServicesVariesAmbulance and emergency management
Debt ServiceVariesBond payments for infrastructure projects

Note: Rates shown are for fiscal year 2025. Total effective rates typically range from $25-40 per $1,000 of assessed value depending on your specific taxing districts. Contact the Union County Assessor at (641) 782-1701 for your exact rate combination.

Section 3

When Are Property Taxes Due?

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

First Installment
Sep 30
Delinquent after Dec 10
Second Installment
Mar 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 Iowa are primarily triggered by new construction, property improvements, or ownership changes that result in a change of assessed value during the tax year. When new construction is completed or substantial improvements are made, the county assessor will issue a supplemental assessment to capture the increased property value for the remainder of the current tax year.

The supplemental tax is calculated by determining the difference between the old and new assessed values, then applying the current tax rate to that difference, prorated for the portion of the tax year remaining. For example, if you complete a $50,000 home addition in January that increases your assessed value by $40,000, and your total tax rate is $30 per $1,000, you would owe an additional $1,200 in supplemental taxes ($40,000 ÷ 1,000 × $30) for that tax year.

Example Calculation

Example 1: $300,000 Home

  • Market Value: $300,000
  • Assessed Value (typically 100% of market): $300,000
  • Homestead Credit Applied: -$4,850 (requires application)
  • Net Taxable Value: $295,150
  • Annual Tax (at $30/$1,000): $8,855
  • Monthly Escrow: $738

Example 2: $600,000 Home

  • Market Value: $600,000
  • Assessed Value: $600,000
  • Homestead Credit Applied: -$4,850 (requires application)
  • Military Exemption (if applicable): -$1,852 (requires application)
  • Net Taxable Value: $593,298
  • Annual Tax (at $30/$1,000): $17,799
  • Monthly Escrow: $1,483

Example 3: $1,000,000 Home

  • Market Value: $1,000,000
  • Assessed Value: $1,000,000
  • Homestead Credit Applied: -$4,850 (requires application)
  • Net Taxable Value: $995,150
  • Annual Tax (at $30/$1,000): $29,855
  • Monthly Escrow: $2,488

Note: Tax rates vary by location within Union County. Credits shown require annual application and eligibility verification.

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Section 5

Escrow & Property Taxes

Most mortgage lenders in Union County require property tax escrow accounts, where monthly payments are collected along with your mortgage payment and held until tax payments are due. Since Union County property taxes are paid in two installments (September and March), your lender will typically collect 1/12th of your estimated annual tax bill each month to ensure sufficient funds are available.

Lenders usually add a cushion of 2-3 months to escrow accounts to cover potential tax increases. Each year, your lender will conduct an escrow analysis and may adjust your monthly payment up or down based on actual tax bills received. You'll receive an annual escrow statement showing all deposits and payments made from your account. If you pay taxes directly rather than through escrow, remember that the first half is due in September and the second half is due by March 1st. Properties with unpaid taxes by April 1st may be listed for tax sale.

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 Union County property taxes due for FY 2025? A: Property taxes are paid in two installments - the first half is due in September, and the second half must be paid by March 1st. If the second half remains unpaid by April 1st, the property may be listed for tax sale.

Q: What tax credits are available and do they require application? A: The Homestead Tax Credit is available for qualifying homeowners and requires annual application through the county assessor's office. A Military Exemption is available for qualifying veterans, also requiring application. As of 2023, a new homestead tax exemption is available for claimants 65 years or older. All credits require application - none are automatic.

Q: How does the Homestead Credit work? A: The Homestead Credit limits assessment increases rather than reducing market value directly. It provides tax relief by capping how much your assessment can increase year-over-year, helping provide property tax stability. You must file annually with the county assessor to maintain eligibility.

Q: How often are properties reassessed in Union County? A: Iowa requires counties to reassess properties periodically to maintain current market values. Contact the Union County Assessor at (641) 782-1701 for the current assessment schedule and to discuss your property's valuation.

Q: What happens if I pay my property taxes late? A: Late payments incur penalties and interest charges. If the second half payment isn't received by March 1st and remains unpaid through April 1st, the property becomes eligible for tax sale proceedings.

Q: Can I pay my property taxes online? A: Contact the Union County Treasurer's office at (641) 782-1701 to inquire about available online payment options and accepted payment methods.

Q: Why do property tax rates vary within Union County? A: Different areas of the county fall within different combinations of special taxing districts including school districts, municipalities, rural fire districts, and emergency service areas. Each district sets its own levy rate, creating different total rates depending on location.

Q: How do I appeal my property assessment? A: Assessment appeals must be filed with the Union County Board of Review during their scheduled meeting period, typically in the spring. Contact the county assessor's office for specific deadlines and procedures.

Q: What triggers a supplemental tax bill? A: New construction, major improvements, or changes in property ownership that affect assessed value during the tax year can result in supplemental tax bills to capture the increased value for the remainder of that tax year.

Q: Where do I apply for property tax credits? A: Applications for Homestead, Military, Family Farm, and other credits are processed through the Union County Assessor's office. Contact them at (641) 782-1701 for application forms and deadlines.

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