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Updated 2025 Tax Year

Sullivan County
Property Tax Guide

Everything you need to know about property taxes in Sullivan County, IN. 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
$1.6129 per $100 assessed value (1.61% effective rate), varies by taxing district
1st Due
May 10
2nd Due
Nov 10
Exemptions
5+ Available
Section 1

How Property Tax Works

Sullivan County, Indiana operates under a property tax system that funds essential local services including schools, libraries, fire protection, and county government operations. The county's property tax rate for 2025 is $1.6129 per $100 of assessed value, as approved by the Sullivan County Board of Commissioners. This translates to an effective tax rate of approximately 1.61% of assessed value, which is above Indiana's statewide average base rate of around 1%.

Property owners should note that actual tax rates can vary significantly depending on your specific location within Sullivan County due to special taxing districts such as school corporations, library districts, fire districts, and other municipal services. Each property's total tax bill reflects the combined rates of all applicable taxing units that serve that particular area. The county assesses all real property at 100% of its true tax value as determined by market-based assessments.

Section 2

What Makes Up Your Tax Bill

ComponentRate (per $100)Description
Total County Rate$1.6129Combined rate for FY 2025
County GeneralVariesBasic county services and operations
School CorporationVariesLocal school district funding
TownshipVariesTownship-level services
Library DistrictVariesPublic library funding (where applicable)
Fire DistrictVariesFire protection services (where applicable)
MunicipalVariesCity/town services (incorporated areas only)

Note: The $1.6129 rate represents a county-wide average. Your actual rate may differ based on the specific combination of taxing districts serving your property location. Special assessments for bonds, TIF districts, or other local improvements may result in additional charges beyond the base rate.

Section 3

When Are Property Taxes Due?

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

First Installment
May 10
Delinquent after Dec 10
Second Installment
Nov 10
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 Sullivan County are typically triggered by significant changes to property ownership or improvements made during the tax year. Common triggers include new construction, substantial renovations that increase assessed value, subdivision of property, or change of use classification. When supplemental taxes are assessed, they represent the pro-rated difference between the old and new tax amounts for the remaining portion of the tax year.

For example, if you complete a $50,000 home addition in July that increases your assessed value, you would receive a supplemental tax bill covering the additional taxes owed from July through the end of the tax year. The calculation would be: ($50,000 × 0.016129) × (6 months ÷ 12 months) = approximately $403 in supplemental taxes. These supplemental bills are issued separately from your regular semi-annual tax bills and have their own due dates as specified by the county treasurer.

Example Calculation

Example 1: $300,000 Home

  • Assessed Value: $300,000
  • Less: Homestead Credit (if applied): Caps assessment increases
  • Net Taxable Value: $300,000
  • Annual Tax: $300,000 × 0.016129 = $4,839
  • Monthly Escrow: $403

Example 2: $600,000 Home

  • Assessed Value: $600,000
  • Less: Homestead Credit (if applied): Caps assessment increases
  • Net Taxable Value: $600,000
  • Annual Tax: $600,000 × 0.016129 = $9,677
  • Monthly Escrow: $806

Example 3: $1,000,000 Home

  • Assessed Value: $1,000,000
  • Less: Homestead Credit (if applied): Caps assessment increases
  • Net Taxable Value: $1,000,000
  • Annual Tax: $1,000,000 × 0.016129 = $16,129
  • Monthly Escrow: $1,344

Note: These examples assume the county-wide average rate. Actual rates vary by taxing district. Tax credits like the Homestead Credit require separate application and primarily limit assessment increases rather than reducing the tax rate.

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Section 5

Escrow & Property Taxes

Most mortgage lenders in Sullivan County require property tax escrow accounts to ensure timely payment of property taxes. Your lender collects approximately 1/12 of your estimated annual tax bill with each monthly mortgage payment, depositing these funds into an escrow account. The lender then pays your property taxes directly to the Sullivan County Treasurer when bills are due on May 10 and November 10.

Lenders typically conduct annual escrow analyses to adjust your monthly payment based on actual tax bills and account balances. If your property taxes increase due to reassessment or rate changes, your monthly escrow payment will be adjusted accordingly. Property owners can verify their tax payments and balances by contacting their lender or checking with the Sullivan County Treasurer's office. Even with escrow accounts, property owners remain ultimately responsible for ensuring taxes are paid on time and should monitor their accounts regularly.

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 Sullivan County? A: Property taxes for FY 2025-2026 are due May 10, 2026 and November 10, 2026. These represent the two semi-annual installments for the current tax year.

Q: What tax credits are available and how do I apply? A: The primary credit is the Homestead Credit, which limits assessment increases on primary residences. You must file an application with the Sullivan County Assessor before April 1 of the assessment year, and reapply every even year. Additional credits may be available for seniors, disabled veterans, or disabled persons - all requiring separate applications.

Q: How does the Homestead Credit work? A: The Homestead Credit doesn't reduce your tax rate but rather caps how much your assessed value can increase each year (typically 10% or less). This credit only applies to your primary residence and requires filing Form 43902 with the county assessor.

Q: What happens if I pay my taxes late? A: Unpaid taxes after the May 10 deadline incur an $8 demand fee. Additional penalties and interest continue to accrue, and properties with delinquent taxes may eventually face tax sale proceedings.

Q: How often are properties reassessed? A: Indiana conducts annual reassessments, but major market-wide reassessments typically occur every few years. Property owners receive assessment notices and have the right to appeal within specified timeframes.

Q: Can I pay my property taxes online? A: Contact the Sullivan County Treasurer's office directly for current online payment options and accepted methods, as these services may vary.

Q: Why do tax rates vary within the county? A: Different areas are served by different combinations of school districts, fire districts, library districts, and municipalities, each with their own tax rates that combine to create your total rate.

Q: How do special district taxes affect my bill? A: If your property is located within special taxing districts (TIF districts, bond districts, etc.), you'll pay additional taxes beyond the base county rate. These appear as separate line items on your tax bill.

Verified Sources

Backed by 10 Official Government Sources

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

01
County
Frequently Asked Questions - Sullivan County Trusteesullivantntrustee.gov
02
County
2025 Sullivan County Budget Orderin.gov
03
Tax Doc
2025 Certified Tax Rates by Districtin.gov
04
Tax Doc
DLGF: Property Tax Due Datesin.gov
05
Tax Doc
Billing and Online Bill PaymentBond Out and Tax ...sullivancounty.in.gov
06
Demand Noticessullivancounty.in.gov
07
DLGF: Exemptionsin.gov
08
County
Property Tax Burden by Countyifo.state.pa.us
09
Tax Doc
Tax Bill Calculator - Indiana Gatewayallencounty.in.gov
10
Sullivan - DLGFin.gov
All sources verified as of 2025 Tax Year

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