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Updated 2025 Tax Year

Gem County
Property Tax Guide

Everything you need to know about property taxes in Gem County, ID. 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
0.544% average (varies by district and special taxing districts)
1st Due
Dec 20
2nd Due
Jun 20
Exemptions
5+ Available
Section 1

How Property Tax Works

Gem County, Idaho operates on a property tax system that funds essential local services including schools, roads, fire protection, and county operations. The property tax system is administered by the Gem County Assessor's Office, which determines assessed values, and the Gem County Treasurer's Office, which handles tax collection and payment processing.

For the 2025 tax year, Gem County has an average property tax rate of 0.544%, which is below Idaho's statewide average. However, your actual tax rate may vary significantly depending on your specific location within the county, as different areas are served by various special taxing districts including school districts, fire districts, highway districts, and other local service providers. These special districts each levy additional taxes to fund their specific services, meaning two similar properties in different parts of Gem County may have substantially different tax bills.

Property taxes in Gem County are calculated based on the assessed value of your property, which is determined annually by the county assessor. Idaho law requires property to be assessed at market value, and reassessments occur regularly to ensure valuations reflect current market conditions. The county assessor updates property values on the first Monday in June each year.

Section 2

What Makes Up Your Tax Bill

ComponentRateDescription
County General0.283%Funds county operations, services, and infrastructure
School DistrictVariesK-12 education funding, varies by school district
Special DistrictsVariesFire, highway, cemetery, and other local service districts
Total Average0.544%Combined rate for FY 2025

Note: These rates apply to the 2025 levy year. Your actual tax rate depends on which special taxing districts serve your property location. School district rates vary significantly across Gem County, and additional levies may apply for services like fire protection, road maintenance, and emergency services. Contact the Gem County Assessor's Office at (208) 365-4561 for your property's specific tax district assignments and applicable rates.

Section 3

When Are Property Taxes Due?

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

First Installment
Dec 20
Delinquent after Dec 10
Second Installment
Jun 20
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 Gem County are additional property tax bills issued when there are changes to property ownership, value, or use that occur after the regular assessment date. The most common triggers include new construction completion, property ownership transfers, changes from exempt to taxable status, or significant improvements that increase property value.

When a supplemental tax is issued, it covers the difference between the original tax bill and what the tax should be based on the new circumstances. The supplemental tax is calculated by determining the new assessed value, applying the current tax rate, and prorating the amount based on how many months remain in the tax year. For example, if you complete a home addition worth $50,000 in January and the tax rate is 0.544%, you would owe approximately $272 in supplemental taxes ($50,000 × 0.00544 = $272) for the remainder of the tax year. Supplemental tax bills are typically mailed within 30-60 days of the triggering event and become delinquent if not paid within 30 days of the bill date.

Example Calculation

Example 1: $300,000 Home

  • Market Value: $300,000
  • Homeowner's Exemption Applied: $125,000 (maximum)
  • Net Taxable Value: $175,000
  • Annual Tax: $175,000 × 0.00544 = $952
  • Monthly Escrow: $79

Example 2: $600,000 Home

  • Market Value: $600,000
  • Homeowner's Exemption Applied: $125,000 (maximum)
  • Net Taxable Value: $475,000
  • Annual Tax: $475,000 × 0.00544 = $2,584
  • Monthly Escrow: $215

Example 3: $1,000,000 Home

  • Market Value: $1,000,000
  • Homeowner's Exemption Applied: $125,000 (maximum)
  • Net Taxable Value: $875,000
  • Annual Tax: $875,000 × 0.00544 = $4,760
  • Monthly Escrow: $397

Note: The Homeowner's Exemption requires annual application and is available only for owner-occupied primary residences. The exemption reduces assessed value by 50% up to a maximum of $125,000. Actual tax rates vary by special district location within Gem County.

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Section 5

Escrow & Property Taxes

Most homeowners in Gem County with mortgage loans have their property taxes collected through an escrow account managed by their lender. Your mortgage servicer estimates your annual property tax bill, divides it by 12, and collects that amount with your monthly mortgage payment. The servicer then pays your property taxes directly to Gem County when they become due.

Lenders typically maintain a cushion in your escrow account to ensure sufficient funds are available when tax bills arrive. Each year, your lender will provide an escrow analysis statement showing the previous year's activity and any adjustments needed for the coming year. If property taxes increase due to rising assessments or rate changes, your monthly escrow payment may increase accordingly. You have the right to review your escrow account annually and request corrections if you believe there are errors in the tax calculations or payments.

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 Gem County for the current fiscal year? A: Personal property declarations must be returned to the county assessor by March 15. Real property tax bills are typically issued in late fall with payment due dates specified on the bill. Contact the Gem County Treasurer's Office for specific due dates.

Q: What tax credits are available and do they require application? A: The primary credit available is the Homeowner's Property Tax Exemption, which requires annual application. This exemption reduces your taxable assessed value by 50% up to a maximum of $125,000 for owner-occupied primary residences. Additional exemptions may be available for seniors, veterans, or disabled persons - all require separate applications.

Q: How does the Homestead exemption work? A: Idaho's Homeowner's Exemption reduces your property's taxable assessed value, not its market value. It exempts 50% of your home's value up to $125,000 maximum for qualifying owner-occupied primary residences. You must apply annually, and all deeded owners must reside in the home to receive the full exemption.

Q: When are properties reassessed and how can I appeal? A: The Gem County Assessor updates property values on the first Monday in June each year. If you disagree with your assessment, you may appeal to the County Board of Equalization. Appeal deadlines and procedures are provided with your assessment notice.

Q: What are the penalties for late property tax payments? A: Late payments incur penalties and interest charges as specified in Idaho Code. Contact the Gem County Treasurer's Office at (208) 365-4288 for current penalty rates and payment options.

Q: Can I pay my property taxes online? A: Check with the Gem County Treasurer's Office for available online payment options and accepted payment methods. Many Idaho counties offer online payment systems for property taxes.

Q: How do special district taxes affect my bill? A: Your property may be located within multiple special taxing districts (school, fire, highway, etc.), each with its own tax rate. These rates are added together to determine your total property tax rate, which is why rates vary by location within Gem County.

Q: What triggers a supplemental tax bill? A: Supplemental taxes are issued for new construction, ownership changes, or property improvements completed after the regular assessment date. The additional tax is prorated for the remaining months in the tax year.

Verified Sources

Backed by 10 Official Government Sources

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

01
Tax Doc
2025 average property tax ratestax.idaho.gov
02
State
Certification of Levy Rates - Idaho State Tax Commissiontax.idaho.gov
03
Tax Doc
Market Values and Property Taxes for 2025tax.idaho.gov
04
Search Category: Property Appraisaltax.idaho.gov
05
State
Property Tax Reduction - Idaho State Tax Commissiontax.idaho.gov
06
County
Important Tax Dates - Ada County Treasureradacounty.id.gov
07
Homeowner's Exemptionjcgov.us
08
State
Homeowner's Exemption - Idaho State Tax Commissiontax.idaho.gov
09
1-685-971-968tax.idaho.gov
10
Short Formapps.irs.gov
All sources verified as of 2025 Tax Year

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