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Updated 2025 Tax Year

Washington County
Property Tax Guide

Everything you need to know about property taxes in Washington 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
17.3151% effective rate (varies significantly by taxing district location within county)
1st Due
Dec 20
Exemptions
5+ Available
Section 1

How Property Tax Works

Washington County, Idaho operates under a property tax system that funds essential local services including schools, roads, public safety, and various municipal services. Property taxes are assessed annually based on market value as of January 1st, with the county maintaining assessment records and collecting taxes on behalf of multiple taxing districts including the county, cities, school districts, and various special service districts.

The effective tax rate in Washington County for 2025 is 17.3151%, though actual rates vary significantly by location within the county depending on which special taxing districts serve your property. These may include fire districts, highway districts, cemetery districts, and other local service areas. Property owners receive annual tax statements by October 25th, with taxes typically due in two installments - the first in December and the second in June of the following year.

Washington County also offers monthly payment plans for property owners who prefer to spread their tax burden throughout the year rather than making lump sum payments. The county assessor's office handles property valuations and exemption applications, while the treasurer's office manages tax collection and payment processing.

Section 2

What Makes Up Your Tax Bill

ComponentRateDescription
County GeneralVariesBasic county services, roads, administration
School DistrictVariesLocal school district operations and facilities
Highway DistrictVariesRoad maintenance and construction
Fire DistrictVariesFire protection and emergency services
Cemetery DistrictVariesCemetery maintenance and operations
Other Special DistrictsVariesVarious municipal services by location
Total Rate (2025)17.3151%Combined rate for all applicable districts

Note: These rates apply to the 2025 tax levy year. Your specific tax rate depends on which special taxing districts serve your property location. The 17.3151% rate represents the combined levy for all districts in certain areas of Washington County. Contact the Washington County Assessor at (208) 414-2380 for your property's specific district assignments and applicable rates.

Section 3

When Are Property Taxes Due?

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

First Installment
Dec 20
Delinquent after Dec 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 Washington County are triggered by changes in property ownership, new construction, or improvements that increase a property's assessed value during the tax year. When these events occur after the January 1st assessment date but before the end of the fiscal year, a supplemental tax bill is issued to capture the additional tax liability.

The supplemental tax is calculated by taking the difference between the new assessed value and the original assessed value, multiplying by the applicable tax rate, and prorating for the portion of the year remaining after the change occurred. For example, if you purchase a home in Washington County in March that was previously assessed at $250,000 but now has a market value of $350,000, you would receive a supplemental bill for the additional $100,000 in assessed value, multiplied by your area's tax rate (such as 17.3151%), and prorated for the remaining 9.5 months of the tax year.

Supplemental tax bills are mailed separately from annual tax statements and have their own due dates, typically 30 days from the bill date. These taxes are in addition to, not instead of, your regular annual property tax bill.

Example Calculation

Example 1: $300,000 Home

  • Market Value: $300,000
  • Assessed Value: $300,000
  • Less: Homeowner's Exemption (if eligible): $125,000
  • Net Taxable Value: $175,000
  • Annual Tax ($175,000 × 17.3151%): $3,030
  • Monthly Payment: $253

Example 2: $600,000 Home

  • Market Value: $600,000
  • Assessed Value: $600,000
  • Less: Homeowner's Exemption (if eligible): $125,000
  • Net Taxable Value: $475,000
  • Annual Tax ($475,000 × 17.3151%): $8,225
  • Monthly Payment: $685

Example 3: $1,000,000 Home

  • Market Value: $1,000,000
  • Assessed Value: $1,000,000
  • Less: Homeowner's Exemption (if eligible): $125,000
  • Net Taxable Value: $875,000
  • Annual Tax ($875,000 × 17.3151%): $15,151
  • Monthly Payment: $1,263

Note: Homeowner's exemption amounts are estimates and require annual application by March 2nd. Actual exemption amounts and eligibility requirements should be verified with the Washington County Assessor's office. Tax rates vary by special district location within the county.

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Section 5

Escrow & Property Taxes

Most mortgage lenders in Washington County require borrowers to establish an escrow account to ensure property taxes are paid on time. Your lender will collect a portion of your annual property tax bill with each monthly mortgage payment, typically dividing your annual tax liability by 12 and adding this amount to your principal and interest payment.

Washington County property taxes are due in two installments - typically in December for the first half and June for the second half. Your lender will make these payments directly to the Washington County Treasurer on your behalf using funds collected in your escrow account. Lenders usually maintain a cushion of 1-2 months of tax payments in the escrow account to ensure sufficient funds are available when payments are due.

You should receive an annual escrow analysis from your lender showing how your tax payments were calculated and whether any adjustments to your monthly escrow contribution are needed. If your property taxes increase due to reassessment or rate changes, your monthly mortgage payment may increase to accommodate the higher escrow requirement. You can verify that your taxes were paid correctly by checking with the Washington County Treasurer's office or viewing your account online.

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

When are property taxes due in Washington County? For the 2025 tax year, property taxes are due in two installments: the first installment in December 2025 and the second installment in June 2026. Tax statements are mailed by October 25th each year.

What tax credits are available and how do I apply? Washington County offers several tax credits including the Homeowner's Exemption and Property Tax Reduction (PTR) benefits. The Homeowner's Exemption requires annual application by March 2nd starting February 1st. PTR applications are accepted January 1st through April 15th. All credits require application - none are automatic.

How does the Homestead/Homeowner's credit work? The Homeowner's Exemption in Idaho reduces your property's taxable assessed value, not the market value. It does not cap assessment increases but provides a fixed reduction in taxable value. You must apply annually and can only claim this exemption on one primary residence.

How often are properties reassessed? Washington County assesses all properties annually as of January 1st. The county uses market sales data and other factors to determine current market values for tax purposes.

What happens if I pay my taxes late? Late property tax payments incur interest and penalties. Contact the Washington County Treasurer at (208) 414-2381 for current penalty rates and interest calculations on delinquent taxes.

Can I pay my property taxes online? Yes, Washington County accepts online property tax payments. Visit the county website or contact the Treasurer's office for online payment options and any associated processing fees.

How do special district taxes work? Special districts like fire, highway, and cemetery districts levy additional taxes based on your property location. These appear as separate line items on your tax bill and fund specific local services in your area.

How do I appeal my property assessment? Property assessment appeals must be filed with the Washington County Board of Equalization by the fourth Monday in June. Contact the Assessor's office at (208) 414-2380 for appeal forms and procedures.

Are monthly payment plans available? Yes, Washington County offers monthly payment plans as an alternative to the standard two-installment payment schedule. Contact the Treasurer's office to enroll in monthly payments.

What triggers a supplemental tax bill? Supplemental taxes are issued when property changes ownership, new construction is completed, or improvements increase assessed value after the January 1st assessment date but during the current 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
County
Washington County Public Access > Property Detailwashcotax.co.washington.or.us
02
County
Washington County Public Access > Property Detailwashcotax.co.washington.or.us
03
Tax Doc
IMPORTANT PROPERTY TAX INFORMATIONco.washington.id.us
04
County
Significant Dates | Washington County, IDco.washington.id.us
05
County
Washington County Public Access > Homewashcotax.co.washington.or.us
06
General Information and Frequently Asked Questionswashingtoncountyor.gov
07
County
Exemption year applied for - Washington County, IDco.washington.id.us
08
Tax Doc
Property Tax Exemptionwashingtoncountyor.gov
09
County
Residential Exemption | Washington County of Utahwashco.utah.gov
10
Tax Doc
Taxing District Date of Election Term of Initiative 2024 2023 2022 ...co.washington.id.us
All sources verified as of 2025 Tax Year

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