A good comparable sale for a Madison property tax appeal is a normal, arm's-length 2025 sale of a home similar to yours in location, size (within about 20% of square footage), age, and style. You need three to five of them. The City of Madison Assessor's dataset has 2,668 residential sales from 2025 — here's how to find the right ones and use them in your objection.
Under Wisconsin assessment law, your home's assessed value should reflect what it would have sold for on January 1, 2026. The evidence the assessor uses — and the evidence you should use — is arm's-length sales of similar properties that occurred during 2025.
Not every 2025 sale counts. Excluded from useful comps:
What you want are normal, market-rate sales of homes that look like yours.
Comparability is about how closely a sold home matches yours on the factors that drive market value. Location is the single biggest factor. A comp two blocks away in your neighborhood is dramatically more useful than a comp three miles away in a similar-looking neighborhood. Buyers pay for school districts, walkability, neighborhood character, and proximity to commercial corridors. Same neighborhood beats same square footage, every time.
Square footage matters next. Aim for comps within about 20% of your home's size. A 1,800 sq ft home is comparable to homes between roughly 1,440 and 2,160 sq ft. Outside that range, the comparison gets noisy.
Age and style matter too. A 1925 bungalow and a 2010 colonial are different products, even at the same square footage. Buyers shop for one or the other. Match style and era when you can.
Lot size matters more than people think, especially in Madison neighborhoods where lots vary substantially. A home on a 5,000 sq ft lot is not the same product as a home on a 12,000 sq ft lot.
Bedrooms, bathrooms, basement, and garage are secondary factors but they matter at the margins. A 3-bed/2-bath comp is more useful for a 3-bed/2-bath subject than a 4-bed/3-bath comp would be.
Condition is the hardest factor to control for, because public records don't always capture condition well — but it's often where the biggest valuation differences hide.
The City of Madison Assessor publishes 2025 sales data through their public records system. This is the same data the assessor uses to build the mass appraisal model that produced your assessment. It's the most authoritative source you can cite.
There are 2,668 actual residential sales in Madison from 2025. Buried in that dataset are the right comps for your specific home — the trick is finding them.
You can also pull data from MLS (if you have an agent helping) and from the County Register of Deeds. But for an objection going to the Madison Board of Assessors, citing City of Madison Assessor data is the strongest move because they can't dispute their own numbers.
For a strong objection, you want three to five comps that all support your opinion of value. Three is a defensible minimum. Five is better. More than seven starts looking like you're cherry-picking, which can backfire.
The comps should cluster around the value you're proposing. If three of your comps suggest $400K and two suggest $480K, the board is going to wonder why you're pointing them at $400K. Pick comps that tell a coherent story.
No comp is identical to your home. Real appraisers make adjustments — adding or subtracting dollars to account for differences. You don't need to be a licensed appraiser to make basic adjustments in your objection.
If your comp has an extra bathroom, subtract a few thousand dollars from its sale price for comparison purposes. If your comp has a finished basement and yours doesn't, subtract for that. If your comp has a brand-new kitchen and yours has a 1990s kitchen, subtract.
You don't need precision. You need to show the board you've thought carefully about why each comp is or isn't directly comparable, and what the adjusted numbers suggest.
The most common errors that weaken otherwise good objections:
Picking comps that are too far away. A sale in Maple Bluff isn't a comp for a home on the near east side, even if the houses look similar. Stay in your neighborhood.
Ignoring sale date. A January 2025 sale and a December 2025 sale happened in different markets. Recency matters.
Using non-arm's-length sales. Foreclosures and family sales aren't market value. Skip them.
Cherry-picking outliers. If most homes in your neighborhood sold in the $400Ks and you cite the one $340K sale, the board will notice. Pick representative comps.
Not adjusting for differences. If your comps all have features your home doesn't, your case looks weaker than it is. Walk through the differences.
In your written objection, you'll list the comp address, sale date, sale price, and key features (square footage, beds, baths, basement, garage, lot size, year built). Then you'll explain why each comp is comparable to your home and what differences exist.
The Board of Assessors does an individual appraisal of your property under Wis. Stat. § 70.075. They're trained to evaluate this kind of evidence. A clean, well-organized comp analysis with three to five strong sales is usually enough to get a meaningful reduction when one is warranted.
The hardest part of this whole process is sifting through 2,668 sales records to find the right comps for your specific home. We built a free tool that does exactly that — pulls the best comps from the City of Madison Assessor's 2025 sales data, walks you through condition factors, and generates a ready-to-send objection email. Use our free tool at mycitymadeeasy.com to check your assessment and build your objection in 2 minutes. No signup, no cost.