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Updated 2025 Tax Year

Carbon County
Property Tax Guide

Everything you need to know about property taxes in Carbon County, MT. 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 - Commercial: 1.40% first $400k, 1.89% above; Agricultural: 2.05%
Exemptions
4+ Available
Section 1

How Property Tax Works

Carbon County, Montana operates under a property tax system that funds essential local services including schools, roads, fire protection, and county government operations. Property taxes are the primary source of revenue for these services, with tax rates varying significantly by location within the county due to different combinations of special taxing districts such as school districts, fire districts, and other local improvement districts.

The county assesses property at market value with different tax rates applied to different property classes. Commercial properties face a rate of 1.40% on the first $400,000 of assessed value and 1.89% on additional value above that threshold, while agricultural property is taxed at 2.05%. Residential properties typically see effective tax rates ranging from 0.8% to 1.5% of market value, depending on their specific location and applicable special district levies. Property owners should note that their actual tax rate depends on which special taxing districts serve their specific property location within Carbon County.

Section 2

What Makes Up Your Tax Bill

ComponentRateDescription
Commercial (first $400K)1.40%Base commercial property tax rate for FY 2025
Commercial (over $400K)1.89%Additional rate on assessed value exceeding $400,000
Agricultural Property2.05%Rate for qualified agricultural land
Multifamily Rental (over $2M)1.89%Maximum rate for large multifamily rental properties
School District LevyVariesAdditional levy depending on school district boundaries
Fire District LevyVariesFire protection services levy where applicable
Special Assessment DistrictsVariesRoad maintenance, water, sewer, and other improvement districts

Note: These rates apply to the 2025 levy year. Actual tax rates vary significantly by property location due to different combinations of special taxing districts. Contact the Carbon County Assessor's Office for rates specific to your property address.

Section 3

When Are Property Taxes Due?

For the 2025/2026 tax year in Carbon 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 Carbon County are triggered when property undergoes changes that affect its assessed value during the tax year. The most common triggers include new construction completion, major improvements or additions, and change of ownership that reveals a significant difference from the current assessed value. When these events occur, the county assessor calculates the difference between the old and new assessed values and applies the current tax rate to determine the supplemental tax amount.

For example, if a property owner completes a $100,000 home addition in March, and the property is subject to a 1.2% effective tax rate, the supplemental tax would be calculated as $100,000 × 1.2% = $1,200 for the remaining months of that tax year. The supplemental tax bill is prorated based on the number of months remaining in the fiscal year from when the improvement was completed or the ownership change occurred.

Example Calculation

$300,000 Residential Property:

  • Market Value: $300,000
  • Less: Homestead Credit Application (if filed): -$15,000 assessment growth limitation
  • Net Taxable Value: $285,000
  • Effective Tax Rate: 1.1%
  • Annual Tax: $3,135
  • Monthly Escrow: $261

$600,000 Residential Property:

  • Market Value: $600,000
  • Less: Homestead Credit (caps assessment increases): -$25,000 potential savings
  • Net Taxable Value: $575,000
  • Effective Tax Rate: 1.25%
  • Annual Tax: $7,188
  • Monthly Escrow: $599

$1,000,000 Commercial Property:

  • First $400,000: $400,000 × 1.40% = $5,600
  • Remaining $600,000: $600,000 × 1.89% = $11,340
  • Annual Tax: $16,940
  • Monthly Escrow: $1,412

Note: These calculations assume average special district combinations. Actual rates vary by property location. Tax credits require separate applications and are not automatically applied.

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Section 5

Escrow & Property Taxes

Most mortgage lenders in Carbon County require borrowers to maintain an escrow account for property tax payments, collecting monthly deposits along with principal and interest payments. Lenders typically collect 1/12th of the estimated annual property tax bill each month, plus an additional cushion amount allowed by federal law. The escrow account ensures property taxes are paid on time, protecting both the homeowner and lender's interests.

Property tax bills are mailed by September 1st each year, and lenders receive copies to verify escrow calculations. If there's a shortage in the escrow account due to tax increases, lenders may require a lump-sum payment or spread the shortage over 12 months. Property owners should review their annual escrow analysis statement and can request to pay taxes directly if they meet certain equity and payment history requirements, though most lenders prefer to maintain escrow accounts for tax payments.

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  • Understand whether your escrow is set correctly
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Section 6

Frequently Asked Questions

When are property taxes due in Carbon County? For the current fiscal year, the first half payment is due by November 10th, and the second half is due by May 10th. Property tax bills are mailed by September 1st.

What tax credits are available and do they apply automatically? Tax credits in Carbon County include the Homestead Credit for primary residences, Disabled Veteran Credits, and Senior Citizen Credits. None of these are automatic - all require separate applications filed with the County Assessor's Office by specific deadlines.

How does the Homestead Credit work? The Homestead Credit doesn't reduce your property's market value but instead caps the annual increase in assessed value for tax purposes. You must apply annually, and the credit limits assessment growth rather than providing a direct tax reduction.

How often is property reassessed in Carbon County? Montana law requires reappraisal cycles every 2 years for residential and commercial properties, with the next county-wide reappraisal scheduled for 2024. Agricultural and forest properties follow the same 2-year cycle but may be assessed in different years.

Can I appeal my property assessment? Yes, property owners can appeal their assessment to the County Tax Appeal Board. Appeals must be filed within 30 days of receiving your assessment notice, typically by June 15th.

What are the penalties for late payment? Late payments incur penalties and interest charges. First-half payments made after November 10th and second-half payments made after May 10th are subject to penalty fees and monthly interest charges.

Can I pay my property taxes online? Contact the Carbon County Treasurer's Office for current online payment options and accepted payment methods. Many Montana counties now offer online payment systems for property taxes.

Why did my taxes increase when property values went down? Tax rates can increase even when property values decrease if local government budgets require more revenue or if special district levies are approved by voters. Your total tax depends on both your property's assessed value and the applicable tax rates for your location.

Verified Sources

Backed by 10 Official Government Sources

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

01
Commissioners Minutescarbonmt.gov
02
Tax Doc
2025 Tax Information for Montana Property Ownersrevenue.mt.gov
03
Overview of Centrally Assessed Property Valuation and ...archive.legmt.gov
04
Tax Doc
Property Tax Overviewgov.mt.gov
05
Tax Doc
Property Tax Calendarcarboncountywy.gov
06
Property Assessmentrevenue.mt.gov
07
Montanairs.gov
08
Tax Doc
Property Taxesgov.mt.gov
09
Tax Doc
Tax Relief for Homesteads and Long-term Rentalsrevenue.mt.gov
10
1 - Authorized Print Version – HB 816archive.legmt.gov
All sources verified as of 2025 Tax Year

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