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Updated 2025 Tax Year

Adams County
Property Tax Guide

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

10 Official Sources
8 min read
Quick Facts
Tax Rate
~5.7933% composite rate (57.933 mills) - varies significantly by location and taxing districts within county
1st Due
Jun 1
2nd Due
Sep 1
Exemptions
5+ Available
Section 1

How Property Tax Works

Adams County, Illinois operates under the state's property tax system, which funds essential local services including schools, municipalities, townships, fire protection districts, and county operations. Property taxes are the primary revenue source for these local government entities, with the Illinois Property Tax Extension Limitation Law (PTELL) providing some limitations on tax levy increases.

The effective property tax rate in Adams County varies significantly by location within the county due to the overlay of different special taxing districts. As of the most recent data available, the composite tax rate is approximately 5.7933% (57.933 mills), though individual property owners may experience different rates depending on their specific school district, municipality, fire protection district, and other local taxing bodies. Property assessments are conducted by the Adams County Supervisor of Assessments, with residential properties assessed at 33.33% of fair market value.

Section 2

What Makes Up Your Tax Bill

ComponentRate (per $100 EAV)Description
County General FundVariableCounty operations, courthouse, sheriff, roads
School DistrictsVariableLocal elementary and high school districts
MunicipalitiesVariableCity/village services (varies by incorporation)
TownshipVariableRoad maintenance, general assistance
Fire ProtectionVariableFire and emergency services
Library DistrictVariablePublic library operations
Other Special DistrictsVariablePark districts, drainage districts, etc.
Total Composite Rate~5.7933%Combined rate for levy year 2023

Note: These rates apply to Equalized Assessed Value (EAV) and vary significantly by specific taxing district boundaries within Adams County. Property owners should verify their specific rate combination through the County Treasurer's office.

Section 3

When Are Property Taxes Due?

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

First Installment
Jun 1
Delinquent after Dec 10
Second Installment
Sep 1
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 property taxes in Adams County are triggered by changes in property ownership, new construction, or significant improvements that increase the assessed value during the tax year. When the County Assessor discovers unreported improvements or reassesses property due to ownership changes, a supplemental assessment is issued for the difference between the original and revised assessments.

The supplemental tax is calculated by applying the current tax rate to the difference in assessed value, prorated for the portion of the tax year the higher assessment applies. For example, if a $50,000 home addition is completed in January and assessed at $16,665 (33.33% assessment ratio), the supplemental tax would be approximately $962 annually ($16,665 × 5.7933% rate) in addition to the original tax bill. Property owners typically receive supplemental bills separately from regular tax bills and should budget accordingly when making significant property improvements.

Example Calculation

Example 1: $300,000 Home

  • Market Value: $300,000
  • Assessed Value (33.33%): $100,000
  • Less: General Homestead Exemption: -$10,000 (if applied for)
  • Net Taxable EAV: $90,000
  • Annual Tax ($90,000 × 5.7933%): $5,214
  • Monthly Escrow: $435

Example 2: $600,000 Home

  • Market Value: $600,000
  • Assessed Value (33.33%): $200,000
  • Less: General Homestead Exemption: -$10,000 (if applied for)
  • Net Taxable EAV: $190,000
  • Annual Tax ($190,000 × 5.7933%): $11,007
  • Monthly Escrow: $917

Example 3: $1,000,000 Home

  • Market Value: $1,000,000
  • Assessed Value (33.33%): $333,333
  • Less: General Homestead Exemption: -$10,000 (if applied for)
  • Net Taxable EAV: $323,333
  • Annual Tax ($323,333 × 5.7933%): $18,726
  • Monthly Escrow: $1,561

All exemptions require annual application and are not automatically applied.

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Section 5

Escrow & Property Taxes

Most mortgage lenders in Adams County require property tax escrow accounts for borrowers with less than 20% down payment. Lenders collect monthly escrow payments equal to 1/12th of the annual property tax bill plus insurance premiums. The escrow account pays property taxes directly to the Adams County Treasurer when bills become due.

Property tax payments in Adams County are due in two installments: typically June 1st for the first installment and September 1st for the second installment, though exact dates may vary annually. Lenders usually pay the first installment in late May or early June and the second installment in late August or early September. Property owners should receive an annual escrow statement from their lender showing account activity and any shortage or surplus adjustments. If property taxes increase significantly due to reassessment or rate changes, lenders may require escrow payment increases or collect shortage amounts over 12 months.

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 Adams County for the current fiscal year? A: Property taxes are typically due June 1st (first installment) and September 1st (second installment), though exact dates may vary. If tax bills are mailed after May 1st, the first installment is due 30 days after the bill date.

Q: What tax credits are available and do they require application? A: The primary credit is the General Homestead Exemption, which reduces EAV by up to $10,000 for owner-occupied residences. This exemption requires annual application through the County Supervisor of Assessments. Senior citizens and disabled veterans may qualify for additional credits, all requiring separate applications.

Q: How does the Homestead Exemption work? A: The General Homestead Exemption reduces your property's Equalized Assessed Value (EAV) by up to $10,000, not the market value. You must apply annually, and the exemption is not automatic. Applications are typically due by the first Tuesday in March.

Q: How often are properties reassessed in Adams County? A: Illinois law requires reassessment at least every four years, though Adams County may conduct more frequent reassessments. Property owners receive assessment notices and have appeal rights through the Board of Review.

Q: What are the penalties for late property tax payments? A: Late payments incur interest charges and penalties. First installment payments made after the due date accrue interest, and second installment late payments face additional penalties. Unpaid taxes can result in tax lien sales.

Q: Can I pay property taxes online in Adams County? A: Yes, Adams County typically offers online payment options through the County Treasurer's website. Payments can also be made at local participating banks or by mail.

Q: Why do tax rates vary within Adams County? A: Different combinations of school districts, municipalities, fire protection districts, and other special taxing districts create varying composite tax rates. Rural properties may have different district combinations than properties within city limits.

Q: How do I appeal my property assessment? A: Assessment appeals must be filed with the Adams County Board of Review within specific deadlines after receiving your assessment notice. The Board of Review typically meets during the summer months to hear appeals.

Q: What happens if I don't apply for available exemptions? A: Exemptions are not retroactive and must be applied for annually by the deadline. Missing the application deadline means you'll pay the full assessed amount for that tax year.

Q: How are special district taxes determined? A: Special districts (schools, fire protection, parks) set their own levy amounts within PTELL limitations. Your specific location determines which districts apply to your property, creating your unique composite tax rate.

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