Appeal a property tax assessment

What does this setup do?

Track the deadline, the reason and the evidence for a property tax appeal, and draft the written appeal your local board asks for.

Who is it for?

Homeowners who think their assessed value is too high and want a clear checklist before the deadline. This is not legal or tax advice. Check dates and forms with your local assessor or board. Do not paste your parcel or account numbers into a chatbot.

How do you set it up?

Tools

• ChatGPT or Claude (free tier is fine)
• Your assessment or change of value notice
• The website or office of your local assessor and appeal board
• Evidence: recent comparable sales, your purchase documents, photos, or an appraisal

Steps

1. Find your assessment notice and write down the assessed value and the date the notice was issued. Deadlines are counted from local rules, so check the date with your local assessor or appeal board.
2. Look up who takes appeals where you live: your local assessor and an appeal board, which may be called a board of review or a board of equalization. This page cannot know your state.
3. Check the deadline with that office. As examples only, Washington's Department of Revenue says it is the later of July 1 of the assessment year or 30 days after the Change of Value Notice, with some counties allowing 60. Illinois tells owners to ask the county board of review for deadlines and forms, and says it is generally too late once you get the tax bill.
4. Pick your reason. As an example, Illinois lists four: the assessor's market value is higher than actual market value, the assessment ratio is higher than the local median, the assessment uses inaccurate facts such as a wrong measurement, or the assessment is higher than similar neighboring properties.
5. Gather evidence. Illinois lists the property record card, photos, records for similar nearby properties, your purchase documents, an appraisal, and recent comparable sales.
6. Ask the assessor to review it first. Washington says many disagreements settle at that level, but you still need to file on time to keep your appeal rights.
7. Ask the chat to draft the written appeal from your facts. File it on your area's official form. Washington says a letter or phone call is not accepted in place of the form.

Help me prepare a property tax assessment appeal. This is not legal or tax advice. I will check every deadline and form with my local office.

I will not paste my parcel number, account numbers or SSN.

My state and county: [state, county]
Assessed value on my notice: [amount]
Date the notice was issued: [date]
Why I think it is too high: [reason]
My evidence: [comparable sales, purchase price and date, errors in the record, photos]

1. Make a checklist with the deadline questions I must confirm with my local office.
2. Sort my evidence into the four reasons: value above market, ratio above local median, wrong facts, higher than similar neighbors.
3. Draft a short written appeal using only my facts.

Show me the checklist first. Do not guess deadlines, forms or my state's rules. Ask me. I file it myself.

Which chat tools work with this prompt?

Paste the prompt into any of these assistants (free or paid tiers).

• ChatGPT
• Claude

What tips make it smoother?

• The Washington and Illinois rules on this page are examples. Do not treat them as your deadline or your appeal authority.
• Illinois says you are appealing the assessed value, not the tax bill, and tax rates are not an issue in the appeal.
• Calling an error to the assessor early may fix it without a formal appeal, per Illinois.
• Washington says to keep the date stamp or postmark: mailed forms must be postmarked by midnight of the deadline.

Where do the claims come from?

Summaries use public sources linked below, not independent verification. How setups are picked.

• Read Washington Department of Revenue’s write-up (dor.wa.gov)

  Washington Department of Revenue: Appealing Your Property Assessment to the County Board of Equalization, opened live 2026-10-29: right to appeal, assessor review first, form required, deadline later of July 1 or 30 days after the notice, some counties 60 days.

• Read Illinois Department of Revenue’s write-up (tax.illinois.gov)

  Illinois Department of Revenue: Assessment Appeals - Property Tax, opened live 2026-10-29: appeal the assessed value not the bill, four reasons, informal and formal appeal, written complaint to the county board of review, evidence list, generally too late after the tax bill.