County assessors mailed out millions of assessment notices this spring, and most homeowners will glance at the number, sigh, and pay it.
Assessment errors are common, and the appeal window in most states closes fast — often 30 to 90 days from the notice date.
The stakes are bigger than they used to be.
Home values surged in many metros between 2020 and 2023, and assessors are still catching up.
Some bills jumped 20% or more in a single year.
But the formula behind that number is often a mass appraisal — a computer model that never walked your street or saw your dated kitchen.
You want three things: your assessed value, the deadline to appeal, and the method your county uses to set value.
Some states cap annual increases, some reassess every year, and some only when a property sells.
Most assessor offices post property records online for free.
Look for errors that are pure fact: wrong square footage, a bedroom count that's off, an extra bathroom that doesn't exist, or a pool you never built.
These are the easiest appeals to win because they don't require arguing about the market.
Find three to five similar homes in your neighborhood that sold within the past year and are assessed for less than yours.
Public sale records and sites like Zillow or Redfin can get you close, though the county's own sales database is stronger evidence.
Adjust for differences — a finished basement or an extra garage bay justifies a gap.
In many states, you can argue your home is assessed at a higher percentage of market value than comparable neighbors.
That's a separate legal claim from "my value is too high," and it sometimes wins when a straight value challenge fails.
Filing is usually cheaper than people expect.
Most counties accept an online form or a one-page petition.
You typically don't need a lawyer for a first-level appeal.
Some homeowners hire a contingency firm that takes 30% to 50% of the savings — worth it only if you have zero time and a strong case.
Photograph everything: the cracked driveway, the water stain, the busy road out front.
Bring your evidence organized in a folder, because hearings are short.
If you lose at the county level, most states allow a second appeal to a board or tax tribunal, and deadlines there are strict too.
Shaving $30,000 off an assessed value in a typical 1.5% tax district saves roughly $450 a year — and that lower base usually carries forward until the next reassessment.
One more thing: don't ignore the notice because you assume everyone's bill went up.
But the county has no incentive to correct a number you never questioned, and the deadline doesn't care whether you read the letter.
Our take: appealing your assessment is one of the few financial moves where a couple of hours of paperwork can pay you back for years.
The system isn't rigged against you so much as it's indifferent — it rewards the people who show up with documents.
Final Thoughts
Check your notice today, because the calendar, not the merits, is what kills most appeals.