How to pull comparable sales from public records for your appeal

Last updated 2026-07-11

What are comparable sales and why do they matter for a tax appeal?

A comparable sale, called a comp, is a property similar to yours that sold recently at arm's length. "Arm's length" means a willing buyer and a willing seller with no special relationship and no pressure, the way most normal home sales work. Assessors in almost every state are legally required to value your property at fair market value, which courts have defined as the price a typical buyer would pay a typical seller in an open market. ^[1]

If your assessed value sits above what similar homes actually sold for, you have a factual argument for a reduction. That argument needs real sales data behind it. Not your gut. Not a Zillow estimate. Tribunals and assessors respond to evidence, and three or four well-chosen comps from public records are the core of almost every successful residential appeal.

Here is the part people miss. The same data the assessor used to set your value is public, and you have the right to it. You do not need to pay an appraiser thousands of dollars to pull it, though in some commercial cases a certified appraisal still earns its cost.

Where can I find comparable sales in public records for free?

You have several free sources, and the best one depends on your county. Start with the assessor. Then the recorder, the state revenue department, and free aggregators as backup.

County assessor or auditor website. Most counties now run a searchable property database where you can look up any parcel by address and see its sale history. Some let you filter sales by date range, neighborhood, or property type. Your county assessor's office is legally required to maintain these records, and most have posted them online. ^[2]

County recorder or register of deeds. This office records every deed transfer. Sale price often shows up in the transfer tax stamps or directly on the deed, though about a dozen non-disclosure states (including Texas, Utah, and Indiana) do not require sale price to be printed on the deed. ^[3] In those states you need a workaround, described below.

State department of revenue or taxation. Many states collect sales data centrally and post it. Illinois publishes Real Estate Transfer Declaration data. California's Board of Equalization publishes sales ratios. Minnesota's Department of Revenue maintains a Sales Ratio Study. ^[4]

Free third-party aggregators. Zillow, Realtor.com, and Redfin pull from the MLS and public records and work fine for finding candidate comps fast. One catch: verify every number back to the county's own records before you submit anything. These sites carry errors.

FOIA or public records request. If your county's online database is thin, file a public records request for a sales extract. Most assessor offices will hand over a spreadsheet of sales within a date range and geographic area inside a few business days, often at no charge. Under most state freedom-of-information laws, property sales records are explicitly public. ^[5]

Which filters should I use when searching for comps?

Pulling the right comps is where most DIY appeals fall apart. Reviewers and hearing officers spot weak comps in seconds, so tighten your filters before you commit to any sale. Six filters matter.

Time window. The standard is sales within 12 months of your assessment date, often called the valuation date or lien date. Some jurisdictions accept up to 24 months if the market held steady, but 12 months is the norm. Check your state's assessment standard; many states publish it. ^[1] If you reach for older sales, note the market conditions and be ready to defend the choice.

Distance. For suburban and urban properties, start with a half-mile radius. If you can't find three good comps that close, expand to one mile. Rural properties may push you out several miles, and then you have to explain any location differences.

Property size. Aim for homes within 20% of your gross living area (GLA). A 2,000 square foot house compared against a 1,400 square foot house draws objections fast. Appraisers and assessors make size adjustments, and so should you (explained below).

Year built. Homes within about 10 years of your build year are safest. Big age gaps change condition, systems, and how buyers see the place.

Sale type. This is the filter most people skip, and it is the one that sinks appeals. Exclude:

• Foreclosure and REO sales (distressed prices don't reflect market value)
• Estate sales and inter-family transfers (often below market)
• Sales between related parties (same family, corporate affiliate)
• Partial interest transfers
• Tax deed sales

States that require a transfer declaration (like Illinois or Ohio) usually put a checkbox on the form for whether the sale was arm's length. ^[6] Use it. In non-disclosure states, cross-reference MLS data or watch for unusual deed language to flag non-arm's-length transactions.

Lot size and configuration. For single-family homes, lot size matters less than the house itself unless you sit on a large acreage parcel. For vacant land appeals, lot size is the main filter.

How many comps do I need, and how similar is similar enough?

Three comps is the working minimum for a residential appeal. Five is better. Appraisers build a sales comparison grid on at least three paired sales for a reason: one or two comps get waved off as outliers, but three or more showing the same pattern is hard to dismiss.

Hearing officers often lean on the Uniform Standards of Professional Appraisal Practice (USPAP) as a benchmark for evidence quality, even in informal hearings. USPAP asks appraisers to analyze enough sales to support a value conclusion, with no fixed minimum, but three to five has become the de facto standard in assessment appeals. ^[7]

How similar is similar enough? A rough scoring approach:

• Same neighborhood or subdivision: ideal
• Same school district and street type (cul-de-sac vs. arterial road): acceptable
• Different neighborhood with similar amenities and price tier: needs explanation

If every comp you find sold below your assessed value, even imperfect comps help. If you cherry-pick one low sale and ignore four nearby sales that back the assessment, expect to lose. Be honest about the pattern before you file, because the assessor will be.

How do I actually pull the data step by step?

Here's the sequence that works in most counties. Five steps, start to finish.

Step 1: Get your own property record card. Go to your county assessor's website and pull up your parcel. Write down the exact recorded square footage, year built, bedroom and bathroom count, and any special features (pool, garage, finished basement). You need this to judge comps against your property. For large counties like Cook County in Illinois or LA County in California, the assessor's portal lets you pull the full property characteristics directly. ^[2]

Step 2: Search sales in your neighborhood. Use the assessor's map or sales search tool. Set your date range (12 months back from the assessment date), set property type to single-family residential, and draw a radius or select the same subdivision. Export or screenshot the results.

Step 3: Pull each candidate comp's record card. For every sale that looks close, pull the full property record and check size, age, bed/bath count, and condition code. Toss anything more than 20% off on square footage.

Step 4: Verify sale validity. Look up the deed in the recorder's database to confirm the sale was arm's length. Check for foreclosure notices (lis pendens) recorded before the sale date. If your county posts transfer declarations, look for the arm's-length confirmation.

Step 5: Record your findings in a simple grid. Show the sales in a table with address, sale date, sale price, square footage, price per square foot, year built, and distance from your property. This table becomes your exhibit.

For a look at how large urban counties handle their public sales data, the Cook County Assessor's tax bill and property record portal is one of the most open in the country and worth studying even if you live elsewhere.

What adjustments do I need to make to my comps?

Raw sale prices are rarely apples to apples. If comp A sold for $320,000 with 200 more square feet than your house, that raw price overstates what your house is worth. You adjust for the gap. This is where DIY filers either skip steps or overbuild.

For a residential appeal you don't need a full USPAP report. You need a simple, defensible adjustment table. Here's how to handle the differences that show up most.

Square footage. If your assessor publishes a cost-per-square-foot figure for your neighborhood (many do, buried in the mass appraisal model documentation), use that as your adjustment rate. Otherwise, look at price per square foot across your comps and apply a modest per-foot adjustment. A common range is $50 to $150 per square foot depending on the market, but justify your number with local data, not a guess.

Garage. A two-car attached garage typically adds $15,000 to $30,000 in a mid-tier suburban market. If your house has no garage and a comp does, subtract that from the comp's price. If your assessor publishes garage contribution values (some do), use those and cite them.

Bathroom count. A full bathroom is often adjusted at $5,000 to $15,000 depending on the market. Half baths run half that.

Sale date. If values moved during your 12-month window, a sale from 11 months back may need a time adjustment. Use your local median price trend from the MLS or the Federal Housing Finance Agency's House Price Index, which publishes quarterly price changes by metro area. ^[8]

Condition. If you can document that your house needs a new roof and a comp was recently renovated, a condition adjustment fits. Photos help a lot here.

Keep adjustments modest and documented. A massive adjustment (more than 20 to 25% of sale price) is a sign the comp was never comparable. Replace it with a better one.

What public records sources work in non-disclosure states?

About 12 states do not require sellers to disclose the sale price on the deed or in a transfer declaration. The commonly cited non-disclosure states include Alaska, Idaho, Indiana, Kansas, Louisiana, Maine, Mississippi, Missouri, Montana, New Mexico, North Dakota, Texas, Utah, and Wyoming, with parts of Nevada and Arizona varying by county. ^[9]

In these states, getting comp prices from public records alone is harder, not impossible.

MLS via Redfin, Zillow, or Realtor.com. MLS data reaches the public through these portals and shows actual closed prices. It is not a government record, but it is real transaction data. Print the listing detail page and the sold confirmation for your exhibit, and note the source.

County appraisal district value histories. Texas has no price disclosure, but each county's central appraisal district (CAD) posts its own appraised values, and many neighborhoods carry enough comparable value data to argue from assessed values rather than sale prices. The Bexar County Appraisal District in San Antonio, for instance, runs a searchable portal where you can pull every parcel's history and the comparable properties used in the CAD's own analysis. See the Bexar County tax assessor guide for a full walkthrough.

Buyer's recorded mortgage as a proxy. The deed of trust or mortgage recorded with the county shows the loan amount. Paired with a typical down payment percentage for the area, you can sometimes estimate the sale price within a reasonable range. This is indirect evidence, so label it that way.

Assessor's sales ratio studies. Several non-disclosure states (Utah, for one) publish sales ratio studies that include median price data by area even without individual prices disclosed. ^[4]

How do I present comps as evidence at my hearing?

Format matters more than most filers realize. A hearing officer working through 30 appeals in a day gives yours maybe 10 minutes. Make your comp evidence impossible to misread.

A single-page sales comparison grid is the format that lands. It should show:

• Your property in the left column
• Three to five comps in the columns after it
• Each row: address, sale date, sale price, GLA (sq ft), year built, beds/baths, garage, distance, price per sq ft, adjustments, and adjusted price

Below the grid, state your conclusion plainly: "The adjusted sale prices of the comparable properties range from $X to $Y, with a mean of $Z. The subject property's assessed value of $W exceeds this range by $V, indicating an overassessment of approximately $V."

Attach printouts of each comp's county record card and the deed or MLS listing confirming the sale price and date. Organize everything in a folder or binder with a cover page listing your parcel number, your name, and your hearing date.

If you want a pre-built grid and instructions, TaxFightBack's DIY appeal kit includes the template used to organize comp evidence in a format hearing officers recognize, plus state-specific filing checklists.

For county-specific filing details in major markets, the Los Angeles County property tax and Montgomery County property tax guides cover the exhibit format those assessors expect.

What mistakes make an assessor or hearing officer reject your comps?

A handful of errors get comp evidence tossed. Here are the ones that show up again and again.

Using distressed sales. A foreclosure that sold 30% below market because the bank wanted a fast close is not evidence of your property's value. If a hearing officer asks "was that an arm's-length sale?" and you can't say yes, the comp is gone.

Geographic cherry-picking. Grabbing a comp on the far side of a busy highway, in a different school district, or in a clearly lower-priced neighborhood when closer sales existed. Assessors know their territories and flag this on sight.

Ignoring the time window. Reaching for a sale from two or three years back in a market that moved. If you use it, show a time adjustment with documented support.

Price per square foot with no adjustments. "The average comp sold for $180 per square foot, so my house should be assessed at $180 times 1,800 square feet" skips condition, age, location, and features. It reads as amateur work.

Confusing assessed value with sale price. Your neighbors' assessed values are not comps. What the assessor says a property is worth is not what a buyer paid for it. Sale prices are the evidence. Assessed values are the thing you're disputing.

No exhibit organization. A stack of Zillow screenshots is worse than nothing. Paginate, label, and organize.

How is pulling comps for a commercial property appeal different?

For commercial property the sales comparison approach still applies, but assessors often weight the income and cost approaches more heavily, and the comp pool is far smaller.

Commercial sales frequently move as entity transfers (LLC to LLC) rather than deed transfers, so they may never show up in the recorder's database. You may need to search SEC filings, paid commercial databases like CoStar, or news coverage of notable deals.

Cap rate evidence often beats raw comp prices in commercial appeals. If you can show the assessor used a 5% cap rate to value your strip mall while the market runs at 7%, you have a strong case no matter what individual sales say.

In large urban commercial markets, the public records infrastructure is usually more detailed than in suburban residential ones. The NYC property tax, LA County property tax, Hennepin County property tax, and Gwinnett County tax assessor guides each cover how those assessors handle commercial comp evidence.

What do state statutes actually say about comparable sales evidence?

State assessment law defines what counts as acceptable evidence in an appeal. Most states authorize the sales comparison approach outright, and several spell out what qualifies as a comparable sale.

California's Revenue and Taxation Code Section 110 defines fair market value as "the amount of cash or its equivalent that property would bring if exposed for sale in the open market under conditions in which neither buyer nor seller could take advantage of the exigencies of the other." ^[10] The State Board of Equalization's guidance treats sales of comparable properties as the primary evidence in residential appeals.

The Illinois Property Tax Code (35 ILCS 200) governs assessment practice in Cook County and across the state. The Illinois Department of Revenue publishes an annual sales ratio study that taxpayers and assessors both use as a benchmark, and that study is public record. ^[4]

Minnesota Statutes Section 273.11 sets the assessment standard (estimated market value at arm's length), and the Minnesota Department of Revenue's sales ratio study documents how closely assessed values track actual sales. ^[4] That study reported a statewide median ratio of assessed value to sales price of 93.0% in fiscal year 2023, meaning the typical Minnesota home is assessed slightly below market, though variation by county runs wide.

For Texas, Tax Code Section 23.01 requires appraisal at market value using generally accepted appraisal methods, and Section 41.43 lets a taxpayer protest on the grounds that the appraised value exceeds the median appraisal ratio of comparable properties. That provision hands you the CAD's own mass appraisal ratios to use against it. ^[11]

Know your state's specific statutory language before a hearing. Print the section and cite it directly.

A quick look at how comp quality affects appeal success rates

Nobody tracks appeal outcomes by evidence quality in a rigorous, nationally published study. The honest answer is that the data is thin and mostly anecdotal. The closest reliable work comes from the Lincoln Institute of Land Policy's research on assessment uniformity, which documents the assessment inequality that appeals exist to correct. ^[12]

What state administrative data does show: the Illinois Property Tax Appeal Board reported that in FY2023, roughly 60% of residential appeals that reached a formal hearing produced some reduction. ^[13] Cook County's own data has long shown that appeals backed by written evidence outperform appeals with none, though the county does not publish that breakdown.

The practical takeaway is blunt. Three clean comps that clearly support your position beat a 20-page report built on questionable data. Quality wins over quantity. Arm's-length recency wins over everything else.

The table below shows which factors most often decide whether a residential comp gets accepted or rejected in administrative hearings, based on standard appraisal practice guidelines.

Frequently asked questions

Can I use Zillow or Redfin data as comp evidence in my appeal?

Yes, with caveats. Third-party sites are not primary sources, so verify the sale price and date against your county recorder or assessor's database before submitting. Print the MLS listing page and the county record together. In non-disclosure states where recorder data doesn't show prices, MLS-sourced data from Zillow or Redfin is widely accepted as secondary evidence.

How many comparable sales do I need for a property tax appeal?

Three is the practical minimum, and hearing officers expect at least that many. Five is better. A single outlier comp gets dismissed easily; three comps showing the same pattern persuades. More than five usually adds diminishing returns unless your property is unusual. All three should be arm's-length sales within the past 12 months and within reasonable geographic and physical proximity.

What is an arm's-length sale and how do I verify one?

An arm's-length sale is between an unrelated willing buyer and willing seller, with no pressure on either side. To verify: check the transfer declaration (available in disclosure states) for the arm's-length checkbox, search for prior foreclosure notices (lis pendens) in the recorder database, and look for unusual deed language like 'love and affection' or 'for nominal consideration,' which signals a non-market transfer.

What if I can't find any comparable sales near my property?

Expand your radius in half-mile increments until you have candidates, then document why you had to go further. For rural properties, two or three miles is often acceptable. If the market genuinely had few sales, supplement with an income approach or cost approach, or argue directly from your county's own sales ratio data showing widespread overassessment in your area.

Do I need to make adjustments to comparable sales, or can I use raw prices?

You need adjustments whenever comps differ from your property in size, features, age, or condition. A hearing officer who sees unadjusted raw prices from bigger or nicer homes will discount your evidence. Adjustments don't need to be complex: a simple table showing size adjustment, garage adjustment, and sale date adjustment covers most residential appeals. Document where your adjustment figures come from.

Where do I find comparable sales in a non-disclosure state like Texas?

Texas deeds don't show sale prices, so use MLS data from Zillow or Redfin as your primary source, verified against the county appraisal district's recorded characteristics. Texas Tax Code Section 41.43 also lets you protest based on the median appraisal ratio of comparable properties, meaning the CAD's own data can work against an inequitable assessment even without individual sale prices.

How far back can my comparable sales be dated?

Twelve months before the assessment valuation date is the standard in most states. Some allow 24 months if the market held steady. Older sales require a documented time adjustment based on a recognized index like the FHFA House Price Index. Check your state's assessment statute or the assessor's published guidelines for the exact cutoff in your jurisdiction.

Can I use a neighbor's assessed value as a comparable instead of a sale price?

No. Assessed values are the assessor's opinion of value, not market evidence. Courts and tribunals treat sale prices as the primary evidence of market value. If your neighbor is also overassessed, using their value just compounds the error. You need actual arm's-length transactions. That said, if your neighbor sold recently, that sale price is exactly the kind of comp you want.

What's the difference between pulling comps myself versus hiring an appraiser?

A licensed appraiser produces a USPAP-compliant report that carries formal credibility, useful for high-value or commercial properties. For most residential appeals, a well-organized DIY comp grid from public records is enough and costs nothing. Save the appraisal expense (typically $300 to $600 for a residential report) for cases where the potential tax savings justify it or where a formal hearing is likely.

How do I find the assessment date or valuation date for my jurisdiction?

Look at your assessment notice, which usually states the lien date or valuation date. If not, check your county assessor's website or your state's property tax code. Common valuation dates include January 1 of the tax year (used by California, Texas, and many other states) and April 1 (used by Maine, among others). Your 12-month comp window runs backward from that date.

What public records databases are best for pulling comps in large counties?

Each major county runs its own portal. Cook County's Assessor portal (cookcountyassessor.com) is especially detailed. LA County's Assessor portal covers over 2.5 million parcels with full sale and characteristic data. Most large counties also run a GIS-based property search that lets you draw a radius and export results. If the portal is thin, file a public records request for a sales extract spreadsheet.

Can I submit comparable sales evidence by mail or does it have to be in person?

This depends entirely on your jurisdiction. Many counties now accept mailed or electronically uploaded evidence packages. Check your appeal notice for the deadline and submission method. Some states require evidence to be submitted a set number of days before the hearing rather than at it. Miss the evidence deadline and your comps can be excluded even if you show up.

What if the assessor presents their own comps that show a higher value?

Ask for those comps in advance if you can, either through a records request or a pre-hearing evidence exchange where allowed. At the hearing, question the arm's-length nature of any comp they use, check the dates, and compare size and features. If their comps are legitimately better, acknowledge it and shift your argument to other grounds like uniformity or the income approach.

Sources

1. International Association of Assessing Officers (IAAO), Standard on Mass Appraisal of Real Property: Fair market value is the standard for property assessment in most U.S. states, defined as the price in an arm's-length transaction between willing parties.
2. Cook County Assessor's Office, Property Search Portal: County assessor portals let taxpayers pull parcel characteristics, sale history, and comparable properties used in mass appraisal.
3. National Association of Realtors, Non-Disclosure States List: Approximately 12 states do not require disclosure of sale price on recorded deeds or transfer declarations.
4. Minnesota Department of Revenue, Sales Ratio Study: The Minnesota statewide median ratio of assessed value to sales price was 93.0% in fiscal year 2023, with significant county-level variation.
5. National Freedom of Information Coalition, State FOIA Laws: Property sales records are explicitly public under most state freedom-of-information laws, and assessor offices must provide them upon request.
6. Illinois Department of Revenue, Real Estate Transfer Declaration (PTAX-203): State transfer declaration forms in Illinois and Ohio include a field indicating whether a sale was an arm's-length transaction.
7. Appraisal Foundation, Uniform Standards of Professional Appraisal Practice (USPAP), 2024-2025 Edition: USPAP requires appraisers to analyze a sufficient number of comparable sales to support a value conclusion; three to five is the de facto standard in assessment appeals.
8. Federal Housing Finance Agency, House Price Index (FHFA HPI): FHFA publishes quarterly house price change data by metropolitan area, which can be used to justify time adjustments to comparable sales.
9. Lincoln Institute of Land Policy, Non-Disclosure States and Assessment Practice: Approximately 12 to 15 states are non-disclosure states where sale price is not required on recorded deeds, complicating comparable sales analysis.
10. California State Board of Equalization, Revenue and Taxation Code Section 110: California R&TC Section 110 defines fair market value as the cash equivalent a property would bring in an open market with no advantage to either party.
11. Texas Comptroller of Public Accounts, Texas Tax Code Section 41.43: Texas Tax Code Section 41.43 allows a taxpayer to protest on the basis that the appraised value exceeds the median appraisal ratio of comparable properties.
12. Lincoln Institute of Land Policy, Significant and Persistent Variation in Assessment Ratios: The Lincoln Institute documents widespread assessment inequality across U.S. jurisdictions that the appeals process is designed to correct.
13. Illinois Property Tax Appeal Board, Annual Report FY2023: Illinois PTAB reported that roughly 60% of residential appeals that went to a formal hearing in FY2023 resulted in some assessed value reduction.