How to challenge a property assessment
The answer
File a written appeal with your county or local assessor before a strict deadline, commonly 30-60 days from your assessment notice, backed by comparable sales evidence, then go through an informal review with an appraiser before, if needed, a formal hearing before an independent review board. Any property owner can do this without a lawyer for a residential appeal. Worth doing if your evidence is solid: nationally only about 3-5% of homeowners appeal, but among those who do, roughly 30-50% win some reduction, and that climbs to 65-85% with well-prepared comparable-sales evidence versus roughly 12% for appeals filed without real documentation.1 Time cost: a few hours to gather comps and file. The process runs weeks to a few months depending on whether it resolves at the informal stage.
Before you go
- Find your assessment notice's date and read the appeal deadline printed on it. This is typically 30-60 days from the notice date and almost always a hard cutoff with no extensions.
- Confirm which office to file with: county assessor, county board of equalization or review, or a separate appeals board, depending on the state.
- Gather 3-5 comparable sales: similar homes in your area, ideally within about half a mile, that sold in the last 6-12 months for less than your assessed value.
- Check your property record card at the assessor's office or website for factual errors (wrong square footage, bedroom or bathroom count, lot size, condition), since factual errors are often the easiest wins.
- Decide whether you'll pursue only the free informal review or plan to continue to a formal hearing if that doesn't resolve it.2
The mechanics
- Read your assessment notice and calendar the appeal deadline immediately.
- Pull your property record card and check it against reality for factual errors.
- Gather comparable sales data (county GIS/property search sites, or a realtor's comparative market analysis) showing similar homes selling for less than your assessed value.
- File a written appeal before the deadline, stating your requested value and the basis. The form varies by county and is often available online.
- Attend the informal review, typically a one-on-one conversation with a county appraiser, and present your comps and any factual corrections.
- If the informal review resolves it, the assessor issues a corrected value and updated tax bill.
- If not, proceed to a formal hearing before an independent board (names vary: Board of Equalization, Property Tax Assessment Appeals Board, Board of Review), where you present evidence and the assessor's office presents its valuation.
- If you lose at the formal county hearing and believe the error is significant, the next level is typically a state tax court or state department of assessments and taxation, a more formal legal proceeding.3
What to say
Lead with the number, then the comps. Assessors and review boards respond to specific dollar comparisons, not general complaints that taxes are too high.
My property at [address] is assessed at $[X]. Based on [3-5]
comparable sales within [0.5] miles, sold within the last
[6-12] months for $[Y average], I am requesting the assessment
be reduced to $[Y]. [If applicable: the property record also
lists (specific factual error), which should be corrected.]
What happens next
Informal reviews are often resolved within a few weeks, sometimes with a same-day verbal indication from the appraiser. If it proceeds to a formal hearing, expect a hearing date weeks to a couple of months out, and a written decision afterward. A successful appeal lowers the assessed value, which lowers that year's tax bill and often carries forward into future assessment cycles unless the county does a full reassessment. If you miss the deadline, you generally cannot appeal until the next assessment cycle, which can mean waiting a full year or longer.
Does it work
Yes, when the evidence is strong. Well-prepared comparable-sales evidence lifts win rates to roughly 65-85%, versus about 12% for appeals filed without real documentation, based on aggregated county appeal-board data rather than a peer-reviewed study, so treat the precise percentages as directional.
Take action
Pull your property record card and check it for factual errors this week. Check /engage for your county's exact deadline and appeal form.