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Updated 2025 Tax Year

Boone County
Property Tax Guide

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

10 Official Sources
8 min read
Quick Facts
Tax Rate
3.57% effective rate (1.00% county base + school/city/district levies)
Exemptions
5+ Available
Section 1

How Property Tax Works

Boone County property taxes fund essential local services including schools, county government operations, emergency services, road maintenance, and various special districts. Property is assessed annually at market value, with taxes calculated based on the assessed value multiplied by the applicable tax rate for your specific location within the county.

The effective property tax rate in Boone County averages approximately 3.57% of assessed value for most parcels, though this varies significantly based on your property's location and the special taxing districts that serve your area. The county base rate is set at 1.00% per hundred dollars of assessed valuation, with additional levies from school districts, cities, townships, and other special districts making up the remainder. Your actual rate depends on which combination of these taxing authorities serve your specific property location.

Property taxes in Boone County are collected on a split-payment schedule, with the first half due September 30th and the second half due March 31st of the following year. The county offers various tax credits for eligible property owners, though most require annual application and are not automatically applied.

Section 2

What Makes Up Your Tax Bill

ComponentRate RangeDescription
County Base Levy1.00%Core county services, confirmed for FY 2025-2026
School DistrictVariesLocal school district operations and bonds
City/MunicipalityVariesMunicipal services (if applicable)
TownshipVariesTownship road maintenance and services
Special DistrictsVariesFire, ambulance, library, and other districts
Total Effective Rate~3.57%Average combined rate across all districts

Note: Your actual tax rate depends on your property's specific location within Boone County and which combination of taxing authorities serve your area. The county base rate of 1.00% applies to all properties, while additional levies vary by district. These rates apply to the FY 2025-2026 levy year.

Section 3

When Are Property Taxes Due?

For the 2025/2026 tax year in Boone 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 are additional property tax bills issued during the tax year when there are changes to your property's assessed value or ownership status. Common triggers include new construction, property improvements, ownership transfers, or corrections to the original assessment.

When supplemental taxes are issued, they are calculated on a pro-rated basis for the remaining portion of the fiscal year. For example, if you complete a home addition in January that increases your assessed value by $50,000, you would receive a supplemental tax bill covering the additional taxes owed from January through June (the remainder of the fiscal year).

The supplemental tax calculation uses the same tax rate structure as your regular property taxes, applied to the change in assessed value. If your property's assessed value increases by $50,000 mid-year and your total tax rate is 3.57%, your supplemental bill would be approximately $1,785 ($50,000 × 3.57%) pro-rated for the remaining months in the fiscal year.

Example Calculation

Example 1: $300,000 Home (with Homestead Credit)

  • Market/Assessed Value: $300,000
  • Homestead Credit Applied: Limits assessment increases, requires application
  • Net Taxable Value: $294,000 (assuming $6,000 homestead exemption)
  • Tax Rate: 3.57%
  • Annual Property Tax: $10,496
  • Monthly (if escrowed): $875

Example 2: $600,000 Home (with Homestead Credit)

  • Market/Assessed Value: $600,000
  • Homestead Credit Applied: Limits assessment increases, requires application
  • Net Taxable Value: $594,000 (assuming $6,000 homestead exemption)
  • Tax Rate: 3.57%
  • Annual Property Tax: $20,806
  • Monthly (if escrowed): $1,734

Example 3: $1,000,000 Home (with Homestead Credit)

  • Market/Assessed Value: $1,000,000
  • Homestead Credit Applied: Limits assessment increases, requires application
  • Net Taxable Value: $994,000 (assuming $6,000 homestead exemption)
  • Tax Rate: 3.57%
  • Annual Property Tax: $35,486
  • Monthly (if escrowed): $2,957

Note: These examples assume qualification for the homestead credit, which requires annual application by July 1st. Actual rates may vary based on your specific location's taxing districts.

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Section 5

Escrow & Property Taxes

Most mortgage lenders require property tax escrow for loans with less than 20% down payment. Your lender collects a monthly amount equal to your annual property tax divided by 12, plus an additional cushion amount (typically 2 months of payments) to ensure sufficient funds are available when taxes are due.

Property taxes in Boone County are due September 30th (first half) and March 31st (second half). Your escrow servicer typically pays these bills directly to the county treasurer on your behalf. It's important to verify that your lender has the correct tax amount, as escrow shortages can result from assessment increases or new special district levies.

If you pay your own property taxes (no escrow), you're responsible for making timely payments to avoid penalties. The county begins charging penalties on October 1st for the first half payment and April 1st for the second half payment. You can verify your current tax amount and payment status through the Boone County Treasurer's office.

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 Boone County for FY 2025-2026? A: The first half is due September 30, 2025, and the second half is due March 31, 2026. Penalties begin the day after each due date.

Q: What tax credits are available and do they require application? A: The primary credit is the Homestead Tax Credit ($6,000 exemption), which requires an initial application filed with the Boone County Assessor by July 1st of the year first claimed. Additional credits may be available for seniors, veterans, or disabled persons - all require separate applications.

Q: How does the Homestead Credit work? A: The Homestead Credit provides a $6,000 reduction in assessed value and helps limit annual assessment increases. It does NOT reduce your property's market value but caps how much your assessment can increase each year. You must apply initially, but it typically renews automatically if you continue to qualify.

Q: When are properties assessed and how can I appeal? A: Properties are assessed annually as of January 1st. Assessment notices are typically mailed in April. You have until May 1st to file an appeal with the Board of Review if you believe your assessment is incorrect.

Q: What are the penalties for late payment? A: Penalties begin at 1.5% per month on overdue amounts, starting October 1st for first half payments and April 1st for second half payments.

Q: Can I pay my property taxes online? A: Yes, Boone County offers online payment options through the Treasurer's website. Check with the Boone County Treasurer's office for current payment methods and any associated fees.

Q: Why did my tax bill increase even though the tax rate didn't change? A: Tax bills can increase due to rising property assessments, new special district levies, or bond measures. Even with stable tax rates, increased property values result in higher tax bills.

Q: What happens if my property is in multiple taxing districts? A: Your tax bill will include levies from all applicable taxing authorities serving your property location, including county, school district, city (if applicable), township, and any special districts like fire or library districts.

Q: How do I apply for tax credits or exemptions? A: Contact the Boone County Assessor's office for applications and specific deadlines. Most credits require annual application by July 1st, and documentation of eligibility is typically required.

Q: What if I disagree with a supplemental tax bill? A: You can appeal supplemental assessments through the same process as regular assessments. Contact the Boone County Assessor's office within the appeal period to discuss your concerns and the appeals process.

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