Comps are your single most powerful weapon in a property tax protest. Here's exactly how to find them on every major platform — and how to use AI to supercharge your research.
A comparable property ("comp") is a home similar to yours that is assessed at a lower value. When you present these to the Appraisal Review Board, you're proving that the county is treating your home unequally — and that's the strongest argument you can make.
Foreclosures, estate sales, divorce sales, new construction, homes in significantly better condition, homes in a different school district, or homes sold in distressed circumstances. The board will dismiss these immediately.
If you purchased your home in the past 1–3 years and the county has assessed it HIGHER than what you paid — your closing disclosure is your single most powerful piece of evidence. Skip the comp research and go straight to your closing documents.
Zillow is the most popular home search site and has excellent sold data going back several years. Here's exactly how to find comps.
On Zillow, look for the "Price/sqft" field on each sold listing. Your goal is to find homes with a lower price/sqft than your assessed rate. To get your assessed rate: divide your assessed value by your square footage. Example: $400,000 assessed value ÷ 2,000 sqft = $200/sqft. Find homes near you that sold for less than $200/sqft.
Redfin is arguably the best platform for finding comps because it shows price trends, detailed sold data, and has a powerful "Compete Score" that tells you how competitive the market is. It also displays price per square foot prominently.
Redfin has a "Market Insights" section for every neighborhood. Go to your neighborhood page and look for the median sale price chart. If prices have declined or flatlined since your last assessment, screenshot that chart — it's powerful evidence that the market doesn't support your assessed value.
Realtor.com pulls data directly from MLS (Multiple Listing Service) — the same database real estate agents use. It often has more complete and accurate data than Zillow for recently sold homes.
On Realtor.com, search your zip code and click "Market Trends". This shows median sale prices, average days on market, and sale-to-list price ratios. If homes are selling below list price in your area, that's evidence the market is softer than your assessed value suggests.
Your county CAD (County Appraisal District) or assessor website is the most powerful source for comps — because it shows the assessed values your neighbors are actually paying taxes on. This is the direct "unequal appraisal" evidence.
CAD comps prove unequal appraisal — the most powerful argument in Texas and most states. You're not arguing about market value. You're showing the county is applying different standards to similar properties on your street. The board cannot easily dismiss this because the data comes from their own records.
AI tools like Claude, ChatGPT, and Perplexity can dramatically speed up your comp research and help you build a stronger case. Here's exactly how to use them.
Use these exact prompts — copy and paste them into any AI tool. Replace the bracketed text with your information.
Perplexity.ai is especially useful because it searches the web in real time. Ask it: "What have homes similar to [your address] sold for in the past 12 months? I need price per square foot data for my property tax protest." Perplexity will pull live data from Zillow, Redfin, and other sources and summarize it for you.
AI tools can sometimes hallucinate addresses or prices. Always verify any specific sale prices or addresses AI provides by checking them directly on Zillow, Redfin, or your county CAD before including them in your protest. Use AI for analysis and argument-building — verify the raw data yourself.
One of the most powerful — and most overlooked — sources for property tax protest comps is a local real estate agent. They have direct MLS access and can pull 3-5 real comparable sales in minutes. And here's the thing most homeowners don't know: many agents are genuinely happy to do this for free.
A lot of people are surprised by this, but there are very practical reasons why agents are often happy to help:
Real estate is a relationship-driven business. If an agent helps you now — quickly, easily, and at no cost — you're far more likely to call them when you decide to sell, refer them to friends or family, or think of them as your go-to real estate person. For many agents, this is a tiny investment for a potentially huge long-term payoff.
High assessed values can make neighborhoods look artificially expensive to maintain. If too many homeowners feel overtaxed, it can discourage buyers, slow down sales, and make homes harder to move. Agents benefit when the market feels fair and accessible — helping homeowners challenge inflated assessments supports that.
Pulling comps is something agents do constantly. For them it's quick, familiar, and low effort — and it makes them look helpful and knowledgeable. It's one of the simplest ways they can provide value without spending hours of work.
Agents want to be seen as the person who knows the neighborhood inside and out. Helping with comps reinforces that reputation. It's a subtle form of marketing — without feeling like marketing.
Most agents have MLS tools that generate comp reports in minutes. If they're already running market analyses for other clients, pulling one more is no big deal.
Once they help you with comps, it's natural for you to ask: "What do you think my home could sell for?" or "Is now a good time to list?" Agents love these conversations because they can lead to listings down the road.
A lot of agents rely on word-of-mouth. If they impress you with fast turnaround, clear data, and professionalism, you're more likely to recommend them. Helping with comps is a low-stakes way to show what they can do.
When you get the comps from the agent, ask them to print it as a formal CMA (Comparative Market Analysis) report. This looks more professional when you present it to the Appraisal Review Board than a handwritten list. An official CMA from a licensed agent carries real weight.
Before you submit your protest, make sure you have all of this:
"My home at [address] is assessed at $[value], or $[$/sqft] per square foot. I identified [number] comparable properties within [distance] that are assessed at an average of $[avg $/sqft] per square foot — [X]% lower than my rate. For example, [comp address], a [sqft] square foot home built in [year], is assessed at just $[comp value] — $[comp $/sqft] per square foot. I'm requesting a reduction to $[requested value] to bring my assessment in line with comparable properties."
Now that you know how to find great comps, let Property Tax Fighter walk you through every step — and write your protest letter for you.
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