Property tax in Ada County, Idaho
The median property tax bill in Ada County, Idaho is $2,655 a year, which is about 0.52% of the county's median home value of $512,300. That effective rate is higher than the typical Idaho county (0.45%) and lower than the national median (0.81%). These are American Community Survey 5-year estimates (2024); your own bill depends on your home's assessed value and any exemptions.
Estimate the property tax on a home in Ada County
Enter a home's market value for a ballpark at Ada County's average effective rate of 0.52% (Census). The real bill depends on the home's assessed value, the millage where it sits and any exemptions.
Estimated property tax: $2,664 / year
Property tax in Ada County at a glance
| Measure | Value |
|---|---|
| Median annual property tax | $2,655 |
| Median home value | $512,300 |
| Effective tax rate | 0.52% |
| Typical Idaho county rate | 0.45% |
| National median county rate | 0.81% |
Effective rate = median real estate taxes paid divided by median home value. Source: U.S. Census Bureau, American Community Survey 5-year estimates.
How does Ada County compare in Idaho?
Among Idaho's 44 counties, Ada County has the 11th highest effective property-tax rate: 10 rank higher and 33 rank lower. That is on the higher side for Idaho. Nationally, it ranks 2565th of 3135 US counties by effective rate. See every Idaho county ranked.
How much do homeowners in Ada County actually pay?
The median is only the middle bill. Across Ada County's 143,399 owner-occupied homes, 39.7% pay $3,000 or more a year in property tax, 66.2% pay at least $2,000, and 4.5% pay under $800. Another 2.4% report paying no property tax at all, which usually means an exemption covers the whole bill.
| Annual bill | Homes | Share |
|---|---|---|
| Under $800 | 6,415 | 4.5% |
| $800 to $1,499 | 18,459 | 12.9% |
| $1,500 to $1,999 | 20,202 | 14.1% |
| $2,000 to $2,999 | 37,997 | 26.5% |
| $3,000 or more | 56,890 | 39.7% |
| No property tax paid | 3,436 | 2.4% |
Owners with a mortgage pay a median of $2,610 and owners without one pay $2,755. That is within 10% either way, so in Ada County paying off the house does not go with a noticeably different bill. Census table B25103.
How does the Ada County property tax bill compare with local incomes?
The median property tax bill of $2,655 is about 2.5% of the median income of Ada County homeowner households, $108,358 a year. That compares two middles, so a retiree in a long-held home can pay a far larger share. 70.8% of Ada County's occupied homes are lived in by their owners; renters pay property tax too, just folded into rent.
Have property taxes gone up in Ada County?
Yes. The median bill went from $1,923 in 2015-2019 to $2,655 in 2020-2024, a 38.1% rise. Over the same span the median home value moved 89.2%, from $270,800 to $512,300. Bills rose more slowly than values, which is what assessment caps and falling millage rates do: the county is taxing a smaller share of each home's worth.
Two Census ACS 5-year periods with no survey years in common, in each period's own dollars. A change counts only if it exceeds the combined 90% margin of error.
Property tax in counties next to Ada County
Ada County borders 5 counties.
| County | Effective rate | Median bill | Median home value |
|---|---|---|---|
| Elmore County, ID | 0.54% | $1,701 | $316,500 |
| Canyon County, ID | 0.52% | $2,011 | $390,000 |
| Ada County, ID (this county) | 0.52% | $2,655 | $512,300 |
| Owyhee County, ID | 0.4% | $1,432 | $359,800 |
| Boise County, ID | 0.34% | $1,611 | $476,100 |
| Gem County, ID | 0.33% | $1,418 | $428,700 |
How is a home assessed in Ada County?
Idaho assesses homes at 100% of market value in every county, Ada County included. How Idaho assesses and reappraises homes.
Is there a homestead exemption in Ada County?
Yes. Idaho's homeowner's exemption takes 50% of a primary home's value off the assessment, capped at $125,000. Apply once through the county assessor. That is the Idaho rule, and it applies in Ada County. Idaho's exemptions and relief programs in full.
When are property taxes due in Ada County?
Counties mail bills in November. The full amount is due by December 20, or you can split it and pay half by December 20 with the second half due by June 20. The June grace period only applies if the first half was paid in full and on time. Miss either deadline and late charges plus interest are added to whatever is outstanding.
Idaho splits the bill into 2 installments. That is the Idaho rule. Ada County issues and collects the bill, so the dates printed on your statement are the ones that bind you.
How to appeal your Ada County property assessment
You contest the assessed value with the county board of equalization, then the Idaho Board of Tax Appeals or district court. The filing deadline is typically the fourth Monday in June for property on the regular roll, or the fourth Monday in November for the subsequent roll. That is the Idaho rule; Ada County sets the exact dates and forms. The Idaho appeal process step by step.
Idaho rules from primary state sources, reviewed September 7, 2026; sources on the Idaho page.
Work out your own numbers
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How much house can I afford?
Your income, debts and down payment against the 28/36 rule lenders actually use, with Ada County's tax rate to hand.
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Mortgage calculator
Monthly payment with principal, interest, tax and insurance, plus what an extra payment saves you.
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Idaho income tax
Brackets, standard deduction and what Idaho actually taxes.
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Sales tax in Ada County
The other local tax: combined state and local rate for this county.
Sources
- Median real estate taxes paid and median home value for Ada County, Idaho: U.S. Census Bureau, American Community Survey 5-year estimates (2020-2024), tables B25103, B25077, B25102, B25119 and B25003; the five-year comparison uses the 2015-2019 estimates. Neighboring counties: Census county adjacency file.