Lesson 8 of 9 · about 15 minutes
Reading a Tax Bill and Comparing Years
You'll be able to
- Identify the parts of an Idaho assessment notice and tax bill
- Know the appeal and payment deadlines
- Split a change in a tax bill into a value effect and a rate effect
- Find which district caused a change, and why
A property tax bill answers "how much." Read it alongside last year's and the assessment notice, and it starts answering "why." That second question is where most people need help, and where most local tax arguments stop too soon.
Two documents, six months apart
The assessment notice arrives first. Idaho Code 63-308 requires the assessor to send it by the first Monday in June. Since January 1, 2024, the notice must show:
- This year's market value and the right to appeal
- Market value for the previous two years
- Property taxes by each taxing district for the previous two years
- The percentage change in each district's tax over those two years
- Each district's budget hearing date, or the deadline for it
- A phone number for each district
That list makes the June notice the best civic document most Idahoans receive, and most of them file it unread. It tells you who to call and which hearing to attend while the budget can still change.
If you think the value is wrong, appeal to the county board of equalization. Idaho Code 63-501 says the board hears appeals received by the end of business on the fourth Monday of June. After that, the value is set for the year.
The tax bill arrives in late November, once levies are approved. Under Idaho Code 63-903 you can pay in full by December 20, or pay half by December 20 and the rest by June 20. Miss the first half and late charges and interest start.
The lines on a bill
| Line | What it means | Where to check it |
|---|---|---|
| Parcel number and tax code area | Identifies the property and the set of districts it sits in | Assessor's parcel lookup |
| Market value | The assessor's value as of January 1 | June assessment notice |
| Exemptions | Homeowner exemption and any others | Lesson 4 table |
| Taxable value | Market value minus exemptions | Do the subtraction |
| District lines | Each district's levy rate and dollars, sometimes split into operating, bond and override | County levy rate table |
| Credits | State-funded relief, such as the homeowner property tax relief created by HB 292 in 2023, and the property tax reduction program for qualifying owners | Treasurer; the reduction program application runs January 1 to April 15 |
| Special assessments and other charges | Non-tax charges like a weed or local improvement district charge | Under 63-1311(2), these need county commissioner approval to appear on the bill |
| Total and halves | What you owe, and when | 63-903 dates |
Comparing two years
When a bill changes, two things moved: your taxable value and the total levy rate. Split them. The method is simple arithmetic, and it ends most arguments.
- Value effect = (new taxable value - old taxable value) x old rate
- Rate effect = new taxable value x (new rate - old rate)
- Value effect + rate effect = total change, exactly
Example: the Alder Street house, 2025 to 2026
Market value rose from $365,000 to $395,000. With the $125,000 exemption, taxable value rose from $240,000 to $270,000. The combined levy fell from 0.008600 to 0.007900.
2025 tax: $240,000 x 0.0086 = $2,064.00
2026 tax: $270,000 x 0.0079 = $2,133.00
Change: +$69.00 (3.3 percent)
Value effect: $30,000 x 0.0086 = +$258.00
Rate effect: $270,000 x (0.0079 - 0.0086) = $270,000 x -0.0007 = -$189.00
Check: $258 - $189 = $69.
So the owner's value rose 8.2 percent in market terms, but 12.5 percent in taxable terms (because the exemption was capped), and falling rates gave most of that back.
Now go district by district. This is where you find out who actually asked for more.
Example: which district moved?
| District | 2025 rate | 2025 tax ($240,000) | 2026 rate | 2026 tax ($270,000) | Change |
|---|---|---|---|---|---|
| Quill County | 0.002300 | $552.00 | 0.002100 | $567.00 | +$15.00 |
| City of Larkspur | 0.003700 | $888.00 | 0.003300 | $891.00 | +$3.00 |
| Kestrel Valley School District | 0.001850 | $444.00 | 0.001900 | $513.00 | +$69.00 |
| Library district | 0.000450 | $108.00 | 0.000400 | $108.00 | $0.00 |
| Ambulance district | 0.000250 | $60.00 | 0.000150 | $40.50 | -$19.50 |
| Cemetery district | 0.000050 | $12.00 | 0.000050 | $13.50 | +$1.50 |
| Total | 0.008600 | $2,064.00 | 0.007900 | $2,133.00 | +$69.00 |
The school line is the only one whose rate went up. Its dollars rose 15.5 percent ($69 / $444). That points to a new voter-approved levy or bond, so check the May and November ballots. The ambulance line fell because an old equipment levy expired. The county and city rates fell, yet their dollars rose slightly, which is the normal pattern under the 3 percent cap with rising values.
Nearly all of this owner's increase came from one district, approved by voters. A complaint aimed at the county would have the wrong board.
Credits and the 2026 utility change
Credits can make a bill look smaller or bigger from year to year for reasons no local board controls. The homeowner property tax relief from HB 292 is paid by the state, and its size depends on state revenue and legislative decisions. Compare bills both before and after credits, and when you cite a figure at a meeting, in testimony or online, say which one you are using.
In 2026 a bigger shift arrived. Under HB 329 of 2025, as the Tax Commission describes it, rate-regulated electric and natural gas companies stopped being valued for property tax starting in 2026 and pay a kilowatt-hour and therm tax instead. The Tax Commission estimates each district's share, and under HB 722 of 2026 every district subtracts that estimate on its L-2 from the property tax it certifies. That changes the taxable value base and the dollars districts levy at the same time. How it nets out for a particular homeowner depends on how much utility property a district had. When you compare 2025 and 2026 bills, ask the county clerk how much utility value left each district's roll and how much kilowatt-hour revenue replaced it.
Common mix-ups
- Claim: My bill went up because the assessor raised my value. What the evidence shows: Part of it may be the value effect. Run the split. Often a rate increase on one voter-approved line explains more.
- Claim: I can appeal my taxes when the bill comes. What the evidence shows: Value appeals go to the board of equalization by the fourth Monday of June. By November it is too late to appeal that year's value.
- Claim: Every line on the bill is a property tax. What the evidence shows: Some are special assessments or other charges the commissioners allowed on the notice. They follow different rules.
Reporting angle
- Each fall, build a "typical home" table: one median-value primary residence, its bill for the last five years, split by district and into value and rate effects.
- Get the county's levy rate table and certified budget table each October after the Tax Commission review.
- Ask the assessor how many valuation appeals were filed and how many succeeded.
- Track credits separately, by year, with the state appropriation behind them.
- Ask the treasurer how many parcels were delinquent after June 20. A rising number is a hardship story.
Research angle
- Idaho Code 63-308: the valuation assessment notice sent to the taxpayer.
- Idaho Code 63-501: the county commissioners meeting as a board of equalization.
- Idaho Code 63-903: when taxes are payable.
- Idaho Code 63-1311: fees for services charged on the tax notice.
- State Tax Commission homeowner's online guide: property tax basics for homeowners.
- State Tax Commission webinar (EPR00112): how levy rates and value changes work.
Check yourself
1. By when must an Idaho county assessor send valuation assessment notices?
Idaho Code 63-308 sets the first Monday in June.
2. To appeal your assessed value to the county board of equalization, the appeal must be received by:
Idaho Code 63-501 has the board hear appeals received by the end of normal business hours on the fourth Monday of June.
3. If you pay the first half of your property tax by December 20, when is the second half due?
Idaho Code 63-903 allows payment in halves: first half by December 20, second half by June 20.
4. A home's taxable value went from $240,000 to $270,000, and its total levy rate went from 0.0086 to 0.0079. How much of the change is the value effect at the old rate?
Value effect = $30,000 x 0.0086 = $258. The rate effect is 270,000 x -0.0007 = -$189. Together: +$69.
5. Which item became part of every Idaho assessment notice starting January 1, 2024?
The 2024 version of 63-308 requires two prior years of value and taxes by district, percentage changes, budget hearing dates and a phone number for each district.
6. A non-property-tax charge, such as a weed control assessment, appears on your tax bill. Under Idaho Code 63-1311, what had to happen first?
63-1311(2) bars charges other than property taxes on a tax notice unless the board of county commissioners approved it and the criteria in 63-902 are met.
Terms in this lesson
- Assessment notice
- The assessor's yearly notice of your property's market value, with appeal rights and, since 2024, prior taxes by district and budget hearing dates.
- Board of equalization
- The county commissioners sitting to hear property value and exemption appeals, through the fourth Monday of June.
- Value effect
- The part of a tax change caused by your taxable value changing, measured at last year's rate.
- Rate effect
- The part of a tax change caused by levy rates changing, measured at this year's value.
- Credit
- A reduction printed on the bill, paid by the state or a program, after district taxes are computed.
Sources
- Idaho Code 63-308, Valuation assessment notice to be furnished to the taxpayer checked 2026-10
- Idaho Code 63-501, Meeting of commissioners as a board of equalization checked 2026-10
- Idaho Code 63-903, When payable checked 2026-10
- Idaho Code 63-1311, Fees for services (charges on the tax notice) checked 2026-10
- Ada County, HB 292 synopsis (homeowner property tax relief, key dates) checked 2026-10
- Idaho State Tax Commission, 2026 Budget and Levy Training, School District Webinar (kWh and therms tax, replacements) checked 2026-10
- Idaho State Tax Commission, Property tax basics guide for homeowners (reduction program dates) checked 2026-10