How to Find Comps for a Property Tax Appeal
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Short answer
Pull comps from your assessor or appraisal district's own records first — the board trusts its own data. Use sales closed before the jurisdiction's valuation date (January 1 in Texas and many states), not the most recent ones. Present three to five adjusted comps with the arithmetic shown. And run both arguments: that your market value is too high, and separately that you are assessed above comparable neighbours — in Texas the second is a statutory ground with its own median test, and most owners never raise it.
Tax appeal comps are not listing comps with a different cover sheet. Three rules change, and each one reverses something that is true in ordinary comp work.
The three rules that flip
| Listing comps | Tax appeal comps | |
|---|---|---|
| Timing | Most recent sales win | Sales before the valuation date win |
| Preferred source | MLS | The assessor's own records |
| Winning argument | What it's worth | What it's worth or how neighbours are treated |
Rule 1 — The valuation date, not today
Your assessment reflects value as of a specific date. In Texas and many other states that is January 1 of the tax year.
So a sale from the previous October is strong evidence. A sale from this June, however similar the house, is largely irrelevant to what the property was worth in January — and in a rising market, submitting it actively hurts you, because it shows a higher number.
This trips up almost every first-time protester. The instinct is to grab the freshest data. Confirm your jurisdiction's valuation date first, then look backwards from it.
Rule 2 — Use the assessor's own data
A review board is being asked to overturn its own district's number. The most persuasive evidence is the district's own records, because it removes any argument about the source.
Most appraisal districts publish a property search showing every parcel's assessed value, square footage, year built, class and condition rating. Many publish sales data too. Start there, and use Redfin or Zillow only to find candidates you then pull from the district.
A screenshot of a Zestimate is the weakest exhibit you can submit. It is a model output about a property that did not sell, and every board has seen a thousand of them.
Rule 3 — Run the equity argument too
This is the one most owners miss entirely, and in Texas it is written into statute.
Texas Tax Code §41.43(b)(3) says a protest on unequal appraisal must be determined in the owner's favour unless the district establishes that the appraised value is equal to or less than the median appraised value of a reasonable number of comparable properties, appropriately adjusted.
Read that carefully, because it does something unusual: it puts the burden on the district, and it makes the median of adjusted comparables the test. You are not arguing about market value at all. You are arguing that whatever the market says, you are assessed above the middle of your comparable set — and that is a violation of uniformity on its own.
The practical consequence: your property can be assessed below market value and you can still win, if neighbours in similar houses are assessed lower still. Owners routinely skip this because it feels like it should not work. It is the statutory ground.
Outside Texas, most states have an equivalent uniformity or equalisation provision, though the mechanics and the burden differ. Check your own statute — the argument usually exists in some form.
How to build each argument
The market value argument
- Find your jurisdiction's valuation date.
- Pull arm's-length sales of similar properties that closed in the 6–12 months before it.
- Screen to three to five: same neighbourhood, similar size, age and condition.
- Adjust each toward your property and show the arithmetic.
- Conclude a value, and compare it to your assessment.
The equity argument
- Pull assessed values for comparable properties from the district's records — not sale prices, assessed values.
- Adjust for real differences in size, age and condition.
- Compute the median of the adjusted set.
- If your assessment exceeds it, that is your case.
Expressing both on a per-square-foot basis makes the comparison legible, but be careful: price per square foot is non-linear, so a much larger or much smaller comparable will distort the figure. Keep the size band tight.
Evidence that helps, beyond comps
Condition is the strongest supplement, because mass appraisal models cannot see it. A district values thousands of properties with a model; it has never been inside your house.
- Photographs of defects — roof, foundation, dated systems, deferred maintenance.
- Contractor estimates for needed repairs. A written quote is a number the board can act on.
- Location disadvantages the model missed — backing an arterial, adjacent commercial use, drainage.
- Your own recent purchase price, if you bought near the valuation date in an arm's-length sale. Often the single strongest piece of evidence available.
- Errors in the record — wrong square footage, a bathroom you do not have, a garage counted twice. Check this first; it is common and it is the easiest correction to win.
The Texas non-disclosure wrinkle
Texas does not record sale prices publicly. That cuts both ways in a protest.
It limits what you can find independently — free sites show estimates, not verified prices. It also limits what the district can assert, and means MLS-derived evidence or a documented recent purchase carries real weight when you have it.
It is also why the equity argument is disproportionately useful in Texas: assessed values are public, even when sale prices are not. You can always build the equity case from district records, whatever the sales data looks like.
How to present it
Boards are not hostile, but they are fast and they see a lot of cases. What works:
- One page summarising your conclusion and the number you are asking for.
- A comparison grid: your property in the first column, each comp beside it, adjustments shown as line items.
- Source labels on every figure — district record, MLS, closing statement.
- Photographs, if condition is part of the argument.
- A specific number, not "it seems high."
Show the arithmetic. An adjustment nobody can follow reads as a guess, and a board that cannot verify your reasoning will default to the district's.
Is it worth doing?
Firms in this market publish figures suggesting only around a fifth of Texas homeowners protest annually, that a majority of protests produce some reduction, and that successful ones average roughly a 10–15% cut. Those numbers come from companies selling protest services, so treat them as indicative rather than authoritative — they have an interest in the answer.
The structural point survives the caveat: most owners never file, informal hearings are usually short, and correcting a factual error in the record is often the whole case.
The bottom line
Work backwards from the valuation date, not forwards from today. Pull comps from the assessor's own records. Build both the market-value case and the equity case, because they can fail independently and in Texas the second has a statutory median test with the burden on the district. Show every adjustment.
And check your property record for errors before anything else. The cheapest win in property tax is a bathroom you were never assessed correctly for.
Frequently asked questions
What comps should I use for a property tax appeal?
Sales of similar nearby properties that closed before your jurisdiction's valuation date, drawn where possible from the assessor's own sales records. Three to five well-matched, clearly adjusted comps are stronger than a long list. Recent sales after the valuation date are usually inadmissible for the value argument, however relevant they feel.
What is the valuation date for a property tax appeal?
The date your property's taxable value is measured as of. In Texas and many other states it is January 1 of the tax year. Comps should generally close before that date. A sale three weeks after the valuation date carries much less weight than one three months before it, which is the opposite of listing-comp practice.
What is an equal and uniform or equity appeal?
An argument that your property is assessed higher than comparable properties, regardless of whether the assessed value matches market value. In Texas, Tax Code section 41.43(b)(3) provides that a protest must be determined in favour of the owner unless the district shows the appraised value is equal to or less than the median appraised value of a reasonable number of appropriately adjusted comparable properties. It is a separate ground from market value and can win even when the market-value argument fails.
Can I use Zillow comps for a property tax appeal?
You can submit them, but they carry little weight. Review boards prefer their own district's sales records and verified sources, and a Zestimate is a model output rather than a transaction. Use public sites to find candidates, then pull the corresponding record from the assessor to present.
How many comps do I need for a tax appeal?
Three to five, adjusted and clearly explained. Boards reward transparent arithmetic far more than volume. A short set where every adjustment is shown and justified is more persuasive than fifteen unadjusted sales.
Sources
- Texas Tax Code §41.43(b)(3) — a protest on unequal appraisal is determined in favour of the protesting party unless the appraisal district establishes that the appraised value is equal to or less than the median appraised value of a reasonable number of comparable properties appropriately adjusted. Comparability is determined by the characteristics described in §23.013(d), and adjustments must be developed and quantified in accordance with generally accepted appraisal standards.
- January 1 valuation date reflects Texas practice and that of many other states; confirm your own jurisdiction's date, as it varies.
- Texas protest participation and outcome figures (commonly cited as roughly 17–24% of owners protesting annually, 60–80% of protests producing some reduction, and average reductions around 10–15%) are published by property-tax-protest firms — interested parties marketing their own services. They are not official state statistics and are cited here as indicative only.
- Texas is a non-disclosure state: sale prices are not recorded in public records, which is why the appraisal district's own sales data and MLS-derived evidence carry disproportionate weight in a Texas protest.