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Updated 2025 Tax Year

Grundy County
Property Tax Guide

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

10 Official Sources
8 min read
Quick Facts
Tax Rate
Varies by district - projected 15.29% rural increase, 16.95% urban increase for FY 2025-2026
1st Due
Sep 30
2nd Due
Mar 31
Exemptions
4+ Available
Section 1

How Property Tax Works

Grundy County, Iowa operates under the state's property tax system to fund essential local services including education, emergency services, infrastructure maintenance, and county operations. Property taxes are levied based on assessed valuations and varying tax rates that depend on your specific location within the county due to different school districts, municipalities, and special taxing districts.

For the FY 2025-2026 tax year, Grundy County faces significant rate increases, with urban taxpayers seeing a projected 16.95% increase and rural taxpayers experiencing a 15.29% increase compared to the previous year. The actual tax rates vary considerably based on which taxing districts serve your property, including school districts, city services, and other special assessments. Iowa's base property tax rate averages around 1% statewide, but your effective rate in Grundy County will depend on your specific location and applicable district levies.

Section 2

What Makes Up Your Tax Bill

ComponentDescriptionNotes
County General ServicesBasic county operations, roads, law enforcementApplied countywide
Rural Basic ServicesAdditional services for unincorporated areasRural properties only
School District LevyK-12 education fundingVaries by school district
Municipal LevyCity services and infrastructureIncorporated areas only
Community CollegeIowa Valley Community College DistrictApplied countywide
Agricultural ExtensionCounty extension servicesApplied countywide
Special AssessmentsDrainage districts, library districts, etc.Location-specific

Levy Year: FY 2025-2026 (taxes payable in 2025) Rate Variations: Tax rates differ significantly based on your property's location within Grundy County. Rural properties face different service levies than urban properties, and each municipality and school district has its own additional rates.

Section 3

When Are Property Taxes Due?

For the 2025/2026 tax year in Grundy 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 Grundy County are additional property tax assessments that occur when there are changes to property ownership, value, or use during the tax year. These typically arise from new construction completed after the January 1 assessment date, property improvements that increase value, or changes in property classification (such as agricultural to residential).

Supplemental taxes are calculated by applying the current year's tax rate to the difference between the original assessed value and the new assessed value. For example, if you complete a $50,000 home addition after January 1, and your total tax rate is 3.5%, you would owe approximately $1,750 in supplemental taxes for that improvement, prorated for the portion of the year the improvement was completed. These supplemental bills are issued separately from your regular tax statement and have their own due dates.

Example Calculation

$300,000 Property (with Homestead Credit):

  • Assessed Value: $300,000
  • Homestead Credit Applied: Limits assessment increase to inflation rate
  • Estimated Tax Rate: 3.2%
  • Annual Tax: $9,600
  • Monthly Escrow: $800 Homestead credit application required annually

$600,000 Property (no credits):

  • Assessed Value: $600,000
  • No Credits Applied: Full assessment
  • Estimated Tax Rate: 3.4%
  • Annual Tax: $20,400
  • Monthly Escrow: $1,700

$1,000,000 Property (with Military Credit):

  • Assessed Value: $1,000,000
  • Military Service Credit: Up to $1,852 reduction in taxes
  • Estimated Tax Rate: 3.5%
  • Annual Tax Before Credit: $35,000
  • Annual Tax After Credit: $33,148
  • Monthly Escrow: $2,762 Military credit requires annual application and verification of service

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Section 5

Escrow & Property Taxes

Most mortgage lenders in Grundy County require property tax escrow accounts to ensure timely payment of property taxes. Your lender collects approximately 1/12 of your estimated annual property tax with each monthly mortgage payment, holding these funds in escrow until tax due dates in September and March.

It's crucial to verify that your mortgage company has current and accurate tax information for your property, especially if you're a new property owner. Contact the Grundy County Treasurer's Office at 319-824-3108 to update your mailing address and ensure your lender receives proper tax statements. Your escrow account will be analyzed annually, and you may receive a shortage or surplus notice if property taxes increase significantly, such as the projected 15-17% increases for FY 2025-2026. Always review your escrow statements and contact your lender immediately if you notice discrepancies in tax amounts or payment timing.

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 Grundy County? A: Property taxes are due in two installments: September 30th and March 31st for FY 2025-2026. Taxes unpaid by April 1st are subject to tax sale proceedings typically held in June.

Q: What tax credits are available and do they apply automatically? A: No credits are automatic - all require annual application. Available credits include the Homestead Credit (limits assessment increases), Military Service Credit (up to $1,852), and the new Homestead Tax Exemption for residents 65 and older. Contact the County Assessor for applications and deadlines.

Q: How does the Homestead Credit work? A: The Homestead Credit doesn't reduce your home's market value but limits how much your assessed value can increase year-over-year, typically capping increases at the rate of inflation. You must file annually to maintain eligibility.

Q: When are properties reassessed? A: Iowa requires reassessment every two years. Properties are physically inspected on rotating schedules, with assessment notices typically mailed in April. You have until May 1st to appeal your assessment.

Q: What are the penalties for late payment? A: Late payments incur interest and penalty charges. After April 1st, unpaid taxes are subject to tax sale proceedings, which can result in loss of property ownership rights.

Q: Can I pay property taxes online? A: Yes, contact the Grundy County Treasurer's Office at 319-824-3108 for online payment options and instructions.

Q: Why do tax rates vary within Grundy County? A: Your total tax rate depends on which taxing districts serve your property, including school district, municipality (if applicable), and special districts like drainage or library districts.

Q: How can I apply for available tax credits? A: Contact the Grundy County Assessor's office for credit applications. Most credits have annual filing deadlines, typically in early July, and require documentation of eligibility such as military service records or proof of age and residency.

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