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Updated 2025 Tax Year

St. Clair County
Property Tax Guide

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

10 Official Sources
8 min read
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Quick Facts
Tax Rate
Varies by district, typically 2.5-4.5% effective rate depending on overlapping taxing districts
Exemptions
5+ Available
Section 1

How Property Tax Works

St. Clair County, Illinois operates under a property tax system that funds essential local services including schools, fire protection, libraries, and county operations. Property taxes are the primary revenue source for these local governments, with the Illinois Property Tax Extension Limitation Law (PTELL) governing how tax levies can increase annually. The county assesses properties at 33.33% of fair market value, with tax bills typically mailed in May and due in installments during the summer and fall.

Effective tax rates in St. Clair County vary significantly by location within the county due to overlapping taxing districts. Property owners may pay taxes to multiple entities including the county, school districts, municipalities, townships, fire protection districts, and special service areas. The combined effective tax rate typically ranges from 3.5% to 5.5% of assessed value depending on your specific taxing districts, with some areas experiencing higher rates due to additional special assessments.

Section 2

What Makes Up Your Tax Bill

ComponentSample RateDescription
St. Clair County4.50%County operations, sheriff, courts, health department
School District (e.g., Belleville)3.75%Local elementary and high school districts
Municipality0.25%-2.50%City/village services (varies by location)
Fire Protection District1.25%Fire and emergency services
Township0.15%-0.30%Road maintenance, general assistance
Library District0.25%-0.40%Public library services
Metro-East Mass Transit0.25%Public transportation (specific areas)
Total Effective Rate3.50%-5.50%Combined rate varies by location

Rates shown are for FY 2024-2025 levy year and represent examples from various districts within St. Clair County. Your actual tax rate depends on which specific taxing districts serve your property location.

Section 3

When Are Property Taxes Due?

For the 2025/2026 tax year in St. Clair 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 St. Clair County are triggered when property ownership changes or when new construction/improvements are completed after the January 1 assessment date. When you purchase property or complete construction, the County Assessor may issue a supplemental assessment to capture the change in value for the current tax year. This supplemental tax covers the period from when the change occurred through the end of the tax year.

The supplemental tax is calculated by taking the difference between the new assessed value and the previous assessed value, multiplying by your area's tax rate, then prorating for the remaining months in the tax year. For example, if you purchase a home in June that increases the assessed value by $50,000, and your total tax rate is 4.5%, you would owe approximately $1,125 ($50,000 × 0.045 × 6/12 months) in supplemental taxes. Property transfers require filing the PTAX-203 Illinois Real Estate Transfer Declaration with the County Recorder's office.

Example Calculation

Example 1: $300,000 Home

  • Market Value: $300,000
  • Assessed Value (33.33%): $100,000
  • Less: General Homestead Credit: -$6,000
  • Net Taxable Value: $94,000
  • Tax Rate: 4.25%
  • Annual Tax: $3,995
  • Monthly Escrow: $333

Example 2: $600,000 Home

  • Market Value: $600,000
  • Assessed Value (33.33%): $200,000
  • Less: General Homestead Credit: -$6,000
  • Net Taxable Value: $194,000
  • Tax Rate: 4.50%
  • Annual Tax: $8,730
  • Monthly Escrow: $728

Example 3: $1,000,000 Home

  • Market Value: $1,000,000
  • Assessed Value (33.33%): $333,333
  • Less: General Homestead Credit: -$6,000
  • Net Taxable Value: $327,333
  • Tax Rate: 5.00%
  • Annual Tax: $16,367
  • Monthly Escrow: $1,364

Note: General Homestead Credit requires annual application and is not automatically applied. Additional credits may be available for seniors, veterans, or disabled persons.

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Section 5

Escrow & Property Taxes

Most mortgage lenders in St. Clair County require property tax escrow accounts for borrowers with less than 20% down payment. Your lender collects monthly escrow payments along with your mortgage payment, then pays your property taxes directly to the County Treasurer when due. Lenders typically collect an initial escrow deposit at closing to ensure adequate funds are available for the first tax payment.

The County Treasurer's office mails tax bills in May, with payment due dates of July 2, September 2, and October 31 (2025 schedule). Your lender should receive these bills and make payments on your behalf. You can verify payments were made by checking the St. Clair County Treasurer's website or calling their office. If you pay your own taxes, you're responsible for ensuring payments reach the Treasurer's office by 4:30 PM on each due date, with electronic payments stopping at 3:00 PM.

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Section 6

Frequently Asked Questions

Q: When are property taxes due for the current year? A: For taxes payable in 2025, the due dates are July 2, September 2, and October 31, 2025. Tax bills are mailed around May 23, 2025. Electronic payments stop at 3:00 PM on due dates.

Q: What tax credits are available and how do I apply? A: The General Homestead Credit reduces your assessed value by up to $6,000 and requires annual application. Senior citizens, veterans, and disabled persons may qualify for additional credits. All credits require separate applications filed with the County Assessor's office.

Q: How does the Homestead Credit work? A: The Homestead Credit primarily limits annual assessment increases to help provide property tax stability for owner-occupied homes. You must apply annually, and it's not automatically granted. The credit can reduce your assessed value but requires proper application and qualification.

Q: What happens if I pay late? A: Late payments incur penalties and interest charges. Properties with unpaid taxes after October 31 are subject to tax sale proceedings, typically held in November. The 2025 tax sale is scheduled for November 3.

Q: How often are properties reassessed? A: St. Clair County conducts periodic reassessments, typically every few years. The County Assessor's office reviews property values and may conduct physical inspections or use statistical analysis to update assessments.

Q: Can I appeal my property assessment? A: Yes, property owners can appeal assessments through the St. Clair County Board of Review. Appeal deadlines are typically in late summer, and you must provide evidence that your property is overvalued compared to similar properties.

Q: Can I pay property taxes online? A: Yes, St. Clair County offers online payment options through their official website. Credit card and electronic check payments are typically accepted, though convenience fees may apply.

Q: Do special taxing districts affect my tax rate? A: Yes, your location within St. Clair County determines which taxing districts serve your property. Some areas have additional taxes for fire protection, library services, or special service areas, which can significantly impact your total tax rate.

Verified Sources

Backed by 10 Official Government Sources

Every fact in this guide is sourced from official county, state, and federal documents.

01
County
St Clair County Il Property Taxnacdashboard.nara.gov
02
70 ILCS 3610/5.01ilga.gov
03
illinoisstclaircountyil.gov
04
County
Real Estate Tax Collection Dates - St. Clair Countyco.st-clair.il.us
05
County
St. Clair County Illinois > Departments > Treasurer > Letterco.st-clair.il.us
06
County
St. Clair County Illinois > Departments > Treasurer > Tax Saleco.st-clair.il.us
07
HB4934ilga.gov
08
County
Homestead Exemptions - St. Clair Countyco.st-clair.il.us
09
Tax Doc
PTAX-343 Application for the Homestead Exemptionstclaircountyil.gov
10
County
PTAX-203-A Supplemental Form A.txt - St. Clair Countyco.st-clair.il.us
All sources verified as of 2025 Tax Year

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