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Updated 2025 Tax Year

Ada County
Property Tax Guide

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

8 Official Sources
8 min read
Quick Facts
Tax Rate
Average 1.09% of assessed value, varies by location (urban 0.652%, rural 0.560%)
1st Due
Dec 20
2nd Due
Jun 20
Exemptions
5+ Available
Section 1

How Property Tax Works

Ada County's property tax system funds essential local services including schools, fire protection, public safety, libraries, and county operations. Property taxes are collected annually based on the assessed value of real estate and personal property, with the revenue distributed among various local taxing districts including the county, cities, school districts, and special service districts.

The average property tax rate in Ada County for 2025 is approximately 1.09% of assessed value, though actual rates vary significantly by location within the county due to different combinations of special taxing districts. Urban areas average around 0.652% while rural areas average 0.560%, with the overall county average at 0.642%. Your specific tax rate depends on which city, school district, fire district, library district, and other special districts serve your property. The Idaho Legislature provided approximately $82 million in property tax relief for Ada County in tax year 2024, helping to reduce the overall tax burden for residents.

Section 2

What Makes Up Your Tax Bill

ComponentRate RangeDescription
Ada County General~0.3%County operations, public safety, courts
School Districts~0.4-0.6%K-12 education, varies by district
City/Municipal~0.1-0.3%City services, varies by municipality
Fire Districts~0.05-0.15%Fire protection and emergency services
Library Districts~0.02-0.05%Public library services
Highway Districts~0.03-0.08%Road maintenance and construction
Other Special Districts~0.01-0.10%Parks, recreation, water, sewer
Total Average Rate1.09%Combined rate for FY 2025-2026

Note: These rates apply to the 2025 levy year and vary significantly by specific location within Ada County. Properties may be subject to additional special assessments or bonds. Check your specific tax bill or use the Property Assessment Records Search to determine your exact rate.

Section 3

When Are Property Taxes Due?

For the 2025/2026 tax year in Ada 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 Ada County are additional property tax bills issued when there are changes to a property's assessed value during the tax year. Common triggers include new construction, major improvements, changes in ownership that remove existing exemptions, or corrections to the original assessment. These supplemental bills ensure that property taxes reflect the current assessed value for the entire tax year.

Supplemental taxes are calculated by determining the difference between the new assessed value and the original assessed value, then applying the current tax rate to that difference. The tax is prorated based on the number of months remaining in the tax year when the change occurred. For example, if you complete a $100,000 home addition in March and your total tax rate is 1.09%, you would owe a supplemental tax of approximately $817 ($100,000 × 1.09% × 9/12 months remaining). Supplemental tax bills are typically mailed within 30-60 days of the assessment change and have the same payment terms as regular property tax bills.

Example Calculation

Example 1: $300,000 Home

  • Market Value: $300,000
  • Assessed Value: $300,000
  • Homestead Exemption (applied): -$125,000
  • Net Taxable Value: $175,000
  • Tax Rate: 1.09%
  • Annual Tax: $1,908
  • Monthly (if escrowed): $159

Example 2: $600,000 Home

  • Market Value: $600,000
  • Assessed Value: $600,000
  • Homestead Exemption (applied): -$125,000
  • Net Taxable Value: $475,000
  • Tax Rate: 1.09%
  • Annual Tax: $5,178
  • Monthly (if escrowed): $431

Example 3: $1,000,000 Home

  • Market Value: $1,000,000
  • Assessed Value: $1,000,000
  • Homestead Exemption (applied): -$125,000
  • Net Taxable Value: $875,000
  • Tax Rate: 1.09%
  • Annual Tax: $9,538
  • Monthly (if escrowed): $795

Note: These examples assume the standard Homestead Exemption has been applied, which requires a separate application. Additional tax relief programs may be available for qualifying residents but require individual applications.

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Section 5

Escrow & Property Taxes

Most mortgage lenders in Ada County require borrowers to maintain an escrow account for property taxes and insurance. Your lender collects 1/12th of your estimated annual property tax bill with each monthly mortgage payment, then pays your property taxes directly to Ada County when they become due. Lenders typically collect an initial escrow deposit at closing and may require a cushion of 1-2 months of payments.

Property tax bills in Ada County are typically mailed in November, with payments due in two installments: the first half due by December 20th and the second half due by June 20th of the following year. If your property taxes are escrowed, your lender will receive the tax bill and make payments on your behalf. You should still review your annual escrow analysis statement to ensure adequate funds are being collected. If your property taxes increase due to reassessment or new special districts, your monthly escrow payment may need to be adjusted. For escrow questions or to verify tax payments, visit the Ada County Treasurer's website at https://adacounty.id.gov/treasurer/ or contact your mortgage servicer directly.

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 Ada County property taxes due for FY 2025-2026? A: Property taxes are due in two installments: first half by December 20, 2025, and second half by June 20, 2026. Full payment can be made by the December deadline.

Q: What tax credits are available and do I need to apply? A: The primary tax credit is the Homestead Exemption, which provides up to $125,000 reduction in taxable value for owner-occupied homes. This requires a separate application and is NOT automatic. Additional credits may be available for seniors, veterans, and disabled persons, all requiring individual applications.

Q: How does the Homestead Exemption work? A: The Homestead Exemption reduces your property's taxable assessed value by up to $125,000, not the market value. You must apply for this exemption - it's not automatic. The exemption also includes a circuit breaker provision that can limit assessment increases for qualifying lower-income homeowners.

Q: When are properties reassessed in Ada County? A: Ada County assesses all properties annually. Assessment notices are typically mailed in April, with appeal deadlines in late June. If you disagree with your assessment, you can appeal through the Board of Equalization process.

Q: What happens if I pay my property taxes late? A: Late payments incur penalties and interest. After December 20th, a 2% penalty is added, with additional penalties accumulating monthly. Properties become delinquent after June 20th and may eventually face tax deed proceedings.

Q: Can I pay my property taxes online? A: Yes, Ada County offers online payment options through their treasurer's website. You can pay by electronic check or credit card, though credit card payments may include processing fees.

Q: Why did my property taxes increase if I didn't make any improvements? A: Tax increases can result from rising property values, new or increased special district levies, school bonds, or loss of previous exemptions. Your tax rate may also change based on the budgets of your local taxing districts.

Q: How do special districts affect my property taxes? A: Special districts provide specific services like fire protection, libraries, or parks. Each district sets its own levy rate, and your property may be served by multiple special districts. These rates vary significantly across Ada County depending on your exact location.

Q: Where can I find more information about Ada County property taxes? A: Visit the Ada County Assessor's Office website at https://adacounty.id.gov/assessor/ for assessment information, exemption applications, and property records. For payment information, visit the Treasurer's office online.

Q: What documentation do I need to apply for the Homestead Exemption? A: You'll typically need proof of ownership, evidence that the property is your primary residence, and a completed application form. Applications must be filed by April 15th of the year you want the exemption to begin. Visit the Assessor's website for specific forms and requirements.

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