Comparable Sales Explained: How to Find Homes That Prove Your Assessment Is Too High

Comparable sales, often called "comps," are one of the strongest kinds of evidence in a property tax appeal. This guide shows you how to choose them, organize them, and present them so your case is easy for the assessor to follow.

What comparable sales are and why they matter

Comparable sales are recent sales of homes similar to yours. Assessors usually estimate your home's value by looking at what similar homes sold for. If your assessment is well above what similar homes actually sold for, that gap is the core of your appeal.

Good comps turn "my taxes feel too high" into "homes like mine sold for less than my assessed value." The second statement is much harder to dismiss.

Start with your own home's facts

Before you search for comps, get your property record card from the county assessor's website or office. Check these details:

Square footage of living space
Bedrooms and bathrooms
Year built and any recorded renovations
Lot size
Garage, basement, pool, or other features
Condition or quality grade, if listed

Errors here are common, and they matter. If the record says you have a finished basement and you don't, fix that first. A factual correction can lower your assessment before you ever need comps.

Also note your current assessed value and, if the county shows it, its estimate of market value. Assessed value and market value can differ depending on local rules, so check which number your county compares against sales.

How to choose comparable sales that hold up

Aim for three to six strong comps. A few close matches beat a long list of loose ones. Here is what to match, in rough order of importance:

Factor	What to look for
Location	Same neighborhood or subdivision if possible. Similar school zone and street type (busy road vs. quiet cul-de-sac).
Sale date	Recent sales, often within the last 6–12 months, or whatever period your county uses.
Size	Living area reasonably close to yours. A common rule of thumb is within 10–20%, but your county may differ.
Age and style	Built in a similar era, with a similar design (ranch, two-story, townhome).
Condition	Similar upkeep and updates. A gutted-and-remodeled home is not a fair match for a dated one.
Lot and features	Similar lot size, garage, basement, and extras like a pool.

Location and timing usually carry the most weight. A near-identical house across town sold two years ago is a weaker comp than a slightly different house on your street that sold last spring.

Be honest about condition

Condition is where homeowners most often go wrong. If your kitchen is original and a comp has new counters and appliances, the assessor will notice. Pick homes in similar shape, or be ready to explain the difference.

Where to find sales data

You have several free or low-cost options:

County records. Many counties publish recent sales, deeds, or transfer records online.
The assessor's office. Staff can often tell you what sales data they use and where to find it.
Public listing sites. Sites like Zillow, Redfin, and Realtor.com show sold prices and basic details. Treat them as a starting point and confirm with county records when you can.
A real estate agent. Some agents will pull a comparable sales report as a courtesy.

Use actual closed sale prices. Asking prices, active listings, and automated estimates are not sales.

What assessors tend to accept and ignore

Rules differ by county, but assessors and review boards tend to respond to the same things.

Usually taken seriously:

Recent arm's-length sales, meaning a normal sale between unrelated parties
Homes in your neighborhood with similar size, age, and condition
Documented problems with your home, such as photos and repair estimates for a bad foundation, roof damage, or water issues
Clear, side-by-side comparison of facts

Often ignored or discounted:

Foreclosures, short sales, and sales between family members, which may not reflect market value
Old sales that predate recent market shifts
Listings that never sold
Online value estimates on their own
Comparisons based only on a neighbor's lower tax bill, with no sales data (some counties do accept "equity" arguments, so ask)
General complaints that taxes have gone up

How to organize your evidence

A tidy package helps the reviewer see your point in minutes. Here is a simple approach:

Make a one-page summary. State your assessed value, what you believe the value should be, and the reason in two or three sentences.
Build a comparison chart. List your home and each comp in columns or rows: address, sale price, sale date, square footage, age, lot size, condition, and notable features.
Adjust for differences, simply. If a comp has an extra bathroom or garage, say so and explain how that might affect price. If you aren't sure how to estimate adjustments, an agent or appraiser can help. Don't make up numbers.
Add photos. Include photos of your home, especially any condition problems. Photos of comps help too, if you have them.
Attach proof. Include county records, closing data, or printouts of sale details, plus repair quotes or inspection reports if relevant.
Keep copies. Bring extras to a hearing and save everything you submit.

Stay factual. A calm, organized presentation is more convincing than a long argument.

Know the limits and risks

A strong set of comps helps, but it doesn't guarantee a reduction. Some things to keep in mind:

The assessor or board may disagree about which sales are truly comparable.
Your evidence might show your value is fair, and in some places a board can raise a value after review.
Savings vary. Many successful appeals save somewhere in the range of a few hundred to a few thousand dollars per year, but results depend on your home, your area, and your tax rate.

If your comps are mixed, with some above and some below your assessment, that is useful information too. It may mean an appeal isn't worth your time.

Check your county's requirements

Appeal rules vary widely. Counties differ on filing deadlines, forms, which sales dates they accept, how many comps they want, and whether you present in writing, online, or at a hearing. Confirm the details with your county assessor or board of review before you start, and file by the deadline. Missing it can mean waiting another year.

This article is general information, not legal or tax advice.

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