How to Find Comparable Sales for a Property Tax Appeal

A comparable sale is a recent, arm's length sale of a home enough like yours in location, size, age, style, condition and lot that its price stands in for what your home would have sold for on the assessment date. Assessors value thousands of homes with a model, and a few well-chosen sales can show the model got yours wrong. The sales that count are nearby, closed rather than listed or pending, close in time to the valuation date, and free of foreclosure or family pricing. This guide covers finding those sales, adjusting them in plain terms, and presenting them so a board actually uses them.

What makes a sale comparable

Start close to home. A sale a few blocks away is stronger evidence than one three miles off, because location alone can move a price more than any other single factor. If you live in a named subdivision or neighborhood, sales inside it beat sales outside it.

Size matters next. Appraisers and assessors generally look for homes within roughly 20 percent of your square footage. A 2,000-square-foot comp is usable for a 1,800-square-foot home; a 3,200-square-foot new build down the street usually is not, unless you adjust hard for the difference.

After location and size, match on:

• Age and style. A 1962 ranch is a weak comp for a 2018 build, even next door. Try to match construction era and architectural style.
• Condition. A fully renovated kitchen and bath set is not the same house as one with original 1970s finishes, even at identical square footage.
• Lot size and type. A quarter-acre lot and a corner lot with no privacy fence are not interchangeable, even with the same house on top.
• School district or neighborhood boundary. Buyers pay for schools. A sale one street over but in a different attendance zone can price very differently from yours.

Three or four strong comps beat a dozen loose ones. A board that sees ten weak matches will discount all of them, while three tight, clearly explained matches are harder to dismiss. If your case is really about a wrong square footage or bedroom count in the county's own file rather than the market, start with seven record errors that inflate assessments instead, since fixing the record can be faster than assembling comps.

The valuation date sets your window

Every appeal argues about value on a specific day, not value in general. California, Georgia, and Florida all key their assessments to January 1. In California, the Board of Equalization describes a decline in value as occurring "in any year in which the current market value of real property is less than its adjusted base year value as of the lien date, January 1." Georgia's Department of Revenue states that property is valued "as of January 1 each year." Florida's property appraiser sets just value as of the same date.

That date sets the window for your evidence. Sales from six months before or after January 1 are more persuasive than sales from a year and a half ago, because markets move. California draws a specific line for decline-in-value cases: the Board of Equalization's Publication 30 says comparable sales should be no later than 90 days after the January 1 lien date. If you are filing a Prop 8 decline-in-value case, read the Prop 8 guide alongside this one, since the comp window and the underlying claim are the same argument.

Georgia and Florida do not publish a numbered day-count for comp recency here. The safe practice is the same everywhere: use sales closest to January 1, and if you must reach further back, explain why.

Where to find sales

You do not need a paid data service to build a comp set.

• The county assessor's or property appraiser's own sales search. Most counties publish a public sales lookup by address or neighborhood, the same site where you found your record card. This is the data the assessor's own staff works from, which makes it hard to dispute.
• The county recorder or clerk of court. Deed and transfer records show the actual recorded sale price and date, useful for confirming a sale found elsewhere.
• Listing sites. These are the best source for photos and a written description of condition, which a county sales database will not give you. Use them to document condition, not to source the price of a sale that has not closed.
• A real estate agent. An agent can pull a comparable market analysis from the local MLS in minutes, often for free, complete with photos and confirmed closing details.

Adjusting for differences in plain terms

No two homes are identical, so every comp needs an adjustment before you compare its price to yours. The idea is simple: add value to a comp for something it lacks that your home has, and subtract value for something it has that yours lacks.

The adjustment logic is the same one an appraiser uses and the one Publication 30 expects a homeowner's comparable-sales analysis to follow. Say a comp sold for $410,000 and has one fewer bathroom than your home. Assume, for illustration, an extra bathroom in your market is worth about $8,000, based on what similar homes with and without one tend to sell for locally. Add that amount to the comp, putting its adjusted value at $418,000. If a different comp has a finished basement worth an estimated $15,000, subtract that amount before comparing it to yours.

Keep every adjustment small and specific: bedroom count, bathroom count, garage, pool, lot size, square footage, condition. Do not adjust for things a buyer would not actually pay for. And show your math. A board does not have to accept your opinion of an adjustment, but a visible, reasoned adjustment is far more persuasive than an unexplained final number.

Why closed sales beat listings and pending sales

A listing price is what a seller hopes to get. A pending sale is a price two parties have agreed to, but the deal can still fall through over financing, inspection, or appraisal. A closed sale is the one number that is final: money changed hands at that price, and it is recorded.

Boards and hearing officers know this, and they weight evidence accordingly. Bring closed sales as your primary evidence. A current listing can support your case as color (it shows what similar homes are asking now), but it should never be your only comp.

Why some sales get excluded

Assessors generally define fair market value around a fair, voluntary transaction. Georgia's statute puts it plainly: fair market value is "the amount a knowledgeable buyer would pay for the property and a willing seller would accept for the property at an arm's length, bona fide sale" (O.C.G.A. section 48-5-2). A sale that does not fit that description is weak evidence of market value, whichever state you are in.

That is why foreclosures and short sales are usually set aside: a lender or a distressed seller is not pricing the home the way a willing seller would. It is also why sales between family members get excluded: the price often reflects estate planning or a favor, not the market. If a sale like this is your only nearby option, say so and explain why, rather than presenting it as an ordinary comp.

Presenting your comps as a one-page grid

However you found your sales, put them on one page. A board member or reviewer looking at a stack of listing printouts has to do your work for you, and busy reviewers do not.

Build a simple grid: your home in the first column, each comp after it, with the same rows for every property. Below is an illustrative example. The address, prices, and adjustments are all fictional and only show the format.

Illustrative example only. The address, dates, and dollar figures are invented to show the format, not real sales.

Publication 30 tells California homeowners to bring exactly this kind of evidence: three adjusted values clustering between $464,000 and $481,000 against an assessed value of $520,000, not one outlier sale but a consistent story from nearby, recent, closed sales. Once your grid is built, the appeal letter template guide shows how to attach it to your state's form or letter.

Checklist before you file

• Comps are closed sales, not listings or pending contracts.
• Comps are within roughly 20 percent of your square footage, or clearly adjusted for the difference.
• Comps are close in location, ideally the same neighborhood or school zone.
• Sale dates cluster around January 1; for a California decline-in-value case, no later than 90 days after the lien date.
• No foreclosures, short sales, or family transfers, unless you have explained why one had to be included.
• Every meaningful difference has a dollar adjustment, not just a description.
• Everything fits on one page, with your home and the comps in the same grid.

Common questions

How many comps do I need?

Three or four strong, well-matched sales usually make a more convincing case than a longer list of loose matches. Quality of match matters more than quantity.

What if nothing comparable sold near me?

Widen the distance before you widen the size or age gap, and say plainly in your presentation that you expanded the search radius because of limited sales. A board would rather see an honest explanation than an unstated stretch.

Do I need a licensed appraiser?

No. For a home, you can gather and present comps yourself using public county data and listing sites. A professional appraisal is one more piece of evidence you can choose to add, not a requirement to appeal.

Can I use an automated home-value estimate instead of actual sales?

Treat automated estimates as a starting point, not evidence. Boards weigh actual closed sales far more heavily than a website's algorithm-generated number, because the algorithm cannot see your home's actual condition.

For the rest of the appeal process once your evidence is ready, see the complete guide. If you would rather not build the grid yourself, a free review from Drop Property Tax includes the comparable sales work.