What contingency property tax firms do that you can do yourself

Last updated 2026-07-09

What does a contingency property tax firm actually do?

A contingency firm does four things. It gets your assessment record, finds comparable sales that support a lower value, files the appeal before the deadline, and argues the case at the hearing. That's the whole job.

The pitch makes it sound like there's a secret process behind a locked door. There isn't. The sales data, the assessment roll, the parcel characteristics, all of it sits in public records you can pull today for free. What a firm adds is time and knowing where to look. This article covers both.

A contingency fee means you pay nothing upfront and the firm keeps a cut of whatever reduction it wins. The National Taxpayers Union Foundation reports that contingency arrangements for residential appeals typically run 25 to 50 percent of the first year's tax savings ^[1]. On a $1,200 annual saving, that's $300 to $600 handed over. Skip the work and it costs you real money.

Here's the bottom line. If you can read a spreadsheet and make one trip to your county assessor's website, you can do what these firms do.

How do contingency firms find out if your assessment is wrong?

The first move is pulling your property record card. That's the assessor's internal file listing square footage, bedroom and bathroom count, lot size, construction grade, and any recorded improvements. If those facts are wrong, the appeal practically wins itself. A finished basement the assessor doesn't know about can add $40,000 to your assessed value. Firms hunt for those errors because they're easy money. You can hunt for them too.

Your property record card is public. Search "[your county] assessor property record" and you'll land on the parcel lookup tool. Print the record. Walk your house with it in hand. Wrong square footage, wrong bathroom count, wrong garage size, a construction grade that overstates your finishes: each is a legitimate ground for a reduction that needs zero market analysis to prove ^[2].

Once the fact-check is done, firms run a ratio study. The idea is plain. Your assessment is supposed to equal a set percentage of market value. Many states assess at 100 percent, but some use a statutory fraction, so confirm your state's ratio before you start ^[3]. If comparable homes recently sold for $350,000 and yours is assessed at $420,000, your assessment sits above market and you have a case.

How do professionals find comparable sales, and how do you do the same thing?

Comparable sales, or "comps," are the backbone of every residential appeal. A firm looks for homes that sold in the 12 months before your assessment date, that are physically similar to yours (within about 20 percent on square footage is a common rule of thumb), and that sit close by, usually within a mile or in your same neighborhood or school district.

Firms pull comps from three places: the Multiple Listing Service through a broker relationship, county deed transfer records, and sometimes a paid service like CoStar or ATTOM. Here's what they leave out of the sales pitch. County deed transfer records are public and free. Many counties publish them through the same parcel search portal used for assessments.

No MLS access? Zillow's "Recently Sold" filter and Redfin's sold-homes map are good stand-ins for residential comps. Neither is perfect. Both pull from public transfer data, and both let you filter by bedroom count, square footage, and sale date. You want three to five sales of homes that are closer to yours than the assessor assumed, and that sold for less than your assessment implies.

For Cook County property tax appeals, the assessor's own website publishes a comparable sales tool built specifically for homeowners to use before filing ^[4]. LA County and Santa Clara also publish sales data through their assessor portals.

One tip that pays off: sort your comps from lowest price per square foot to highest. Your argument is that the assessor used the top of the range and the market says you belong at the bottom. That's a clean story a board can follow.

What does the appeal paperwork actually look like?

Most residential appeal forms run one or two pages. You identify the parcel, state the assessment you're challenging, state the value you think is right, and check a box for the grounds (overvaluation, unequal appraisal, or factual error). Some counties, like Bexar County in Texas or Gwinnett County in Georgia, have online portals that walk you through the form step by step ^[5].

The evidence attachment is where homeowners underprepare and where firms earn their keep. A strong packet has a cover sheet with your parcel number and requested value, a grid comparing your property's characteristics against each comp, photos of any condition problems (deferred maintenance, flood risk, functional obsolescence), and copies of the actual sale records or MLS sheets.

None of that needs a law degree. It needs a table in a Word document and a folder of screenshots. TaxFightBack's DIY appeal kit has a template that formats this automatically, but even a hand-built spreadsheet saved as a PDF does the job.

Deadlines are the one place firms genuinely save people from themselves. Miss the deadline and you're locked out until the next cycle, no exceptions. The rules vary hard by state. Texas gives you 30 days from the assessment notice. Illinois property owners must file board of review appeals within 30 days of the assessment notice publication date ^[9]. New York City's deadline for most properties is March 15 for the following fiscal year ^[6]. Set a calendar alert the day your notice lands.

What happens at the hearing, and do you need a professional to argue your case?

Most residential tax hearings are informal. You sit across a table from a board member or hearing officer for 10 to 15 minutes, present your comps, explain why your home is worth less than assessed, and answer a few questions. No opposing counsel. No formal rules of evidence. No judge.

Firms attend because it's billable time. But informal board hearings in most counties are built for self-represented homeowners. The California State Board of Equalization notes that county appeals boards hear cases from unrepresented owners and that formal rules of evidence do not apply at most informal hearings ^[8]. The Texas Comptroller's guidance says the same about Appraisal Review Board hearings ^[5].

Two things decide the hearing: being organized and being specific. Don't argue that your taxes feel high. Argue that comparable properties at [address] and [address] sold for $X per square foot while your assessment implies $Y per square foot, a gap of Z percent. Boards respond to math, not feelings.

Lose at the informal hearing and most states give you a next step: a formal appeal to the state board of equalization, a small-claims-style tribunal, or district court. That's where a contingency firm earns its fee more honestly, because formal proceedings involve rules of evidence and sometimes cross-examination. Most residential appeals never get that far.

How much do contingency firms charge, and what does that actually cost you?

The standard contingency fee for residential appeals is 25 to 50 percent of the first year's tax savings. In major markets, 33 to 40 percent is the common band. Some firms charge a flat fee per year of savings across a multi-year cycle. A few tack on a small upfront filing fee.

Put a number on it. Say your assessed value drops by $50,000 and your effective tax rate is 2 percent. Your annual savings is $1,000. At a 40 percent fee, you pay $400 and keep $600. You did the same work the firm would have done. Do it yourself and you keep the full $1,000.

That math repeats every year the reduced assessment holds. In many states a successful appeal locks in a lower base value for the full cycle, often two to four years. Over four years, a $1,000 annual saving totals $4,000. A 40 percent fee on year one alone costs $400. DIY saves you that $400 and sometimes nothing more, but $400 is $400.

The table below shows fee ranges by segment, based on publicly disclosed fee structures from major firms.

Segment	Typical fee range	Notes
Residential (single-family)	25 to 40% of year-1 savings	Most common nationally
Residential (high-value, over $1M)	33 to 50% of year-1 savings	Higher fees for complex cases
Small commercial	33 to 50% of year-1 savings	Often multi-year contracts
Large commercial	15 to 30% of multi-year savings	Negotiated; volume discounts

For NYC property owners or Hennepin County commercial properties, the complexity is real and firm expertise matters more. For a three-bedroom house in the suburbs, it doesn't.

What is the actual success rate of DIY appeals versus using a firm?

Nobody has clean apples-to-apples data comparing DIY success rates to firm success rates for residential appeals. Any firm claiming a specific superiority number should be asked to show its methodology.

The closest honest data comes from the Lincoln Institute of Land Policy, whose research shows property owners who appeal win reductions roughly 40 to 70 percent of the time across jurisdictions ^[7]. The wide range reflects how differently assessors set values relative to the market. That figure covers all appellants, represented and not.

In Cook County, Illinois, the assessor's transparency data has shown that most residential appeals are filed by owners without professional representation, and that reduction rates for self-filed appeals are meaningful but often lower in absolute dollars than firm-filed appeals, partly because firms pick the cases with the biggest potential reduction ^[4]. Selection bias, not superior skill, drives most of the perceived gap.

Firms cherry-pick. They turn down appeals with thin evidence because no reduction means no fee. When you file your own, you can size up the same odds a firm would. Assessed at $400,000 and your best comps sold at $390,000? Thin case. Best comps sold at $340,000? File immediately.

What records do you need to pull before you file?

Here's the checklist any competent appeal needs, firm-filed or DIY.

1. Your current assessment notice (mailed annually or on your county portal). 2. Your property record card from the assessor's database, showing the physical characteristics used to set your value. 3. Three to five comparable sales within the past 12 months, with address, sale date, sale price, square footage, and bedroom/bathroom count. 4. Photographs of any condition issues that push your property below the assessor's assumed condition grade. 5. Any independent appraisal you already have (useful, not required; a certified appraisal runs $300 to $500 and is overkill for most residential cases). 6. The specific appeal form for your county and the filing deadline.

Montgomery County in Maryland, for example, publishes all of it, the assessment notice, the appeal form, and the sales database, through a single online portal ^[12]. Most counties with active assessment programs have moved the same way.

One thing firms do well is order and presentation. A clean one-page summary table at the front of your packet, comparing your property against each comp on a per-square-foot basis, makes the board's job easy. Easy jobs get resolved in your favor more often.

Are there situations where hiring a contingency firm actually makes sense?

Yes. If your property is commercial, assessed above roughly $2 million, or valued on the income approach (cap rates, net operating income, expense ratios), the analysis gets genuinely complex and a pro can likely find value you'd miss.

Formal appeals in district court or before a state board carry real procedural weight. If you lost at the informal level and want to push further, talk to an attorney or a licensed property tax consultant.

If you physically can't gather the records, or you're dealing with a property in a state you don't know (say, an inherited house in Texas while you live in Massachusetts), the logistical convenience of a firm can justify the fee.

For St. Louis County personal property tax appeals or Bibb County assessments in Georgia, where local practice varies and assessor relationships matter, a consultant who works that specific county can sometimes move faster than a homeowner learning the system cold.

But for the median single-family owner staring at a notice that's 15 to 25 percent above what the neighbors' homes sold for, a contingency firm is charging you for a task you can finish in three hours.

What is unequal appraisal and why do firms love it?

Unequal appraisal is a second, separate legal theory. Instead of arguing your assessment is above market value, you argue the assessor applied a higher effective ratio to your property than to comparable ones, producing an unfair tax burden even when the dollar value is defensible.

In Texas, Section 42.26 of the Tax Code provides a remedy for unequal appraisal, and the Texas Comptroller's Property Tax Assistance Division puts it this way in its published guidance: "A property is appraised unequally if the appraised value of the property exceeds the median appraised value of a reasonable number of comparable properties appropriately adjusted" ^[10].

Firms love this theory because it works even when market value is hard to dispute. If the assessor values your house at $300,000 and genuinely similar homes down the street are assessed at $260,000, you may have an unequal appraisal case no matter whether $300,000 is a fair market price.

You can run this yourself. Pull five to ten houses similar to yours. Grab their assessed values from the county portal. Calculate each one's ratio of assessed value to recent sale price. If your ratio sits well above the group, that's your argument.

Step-by-step: how to do what a contingency firm does, yourself

Here's the process start to finish.

Step 1: Check your property record card. Pull it from the county assessor's parcel search. Walk your property with it in hand. Note every error.

Step 2: Calculate your implied market value. Divide your assessed value by your county's legal assessment ratio (found in your state's property tax statute or the assessor's FAQ page). That's what the assessor thinks your property is worth.

Step 3: Find three to five comparable sales. Use the county's sales database, Redfin, or Zillow's sold filter. Sort by sale date (within 12 months of assessment date), proximity (within one mile or same neighborhood), and size (within 20 percent of your square footage).

Step 4: Build a comp grid. Put your property and each comp in a table. Columns: address, sale date, sale price, square footage, price per square foot, beds, baths, lot size, year built. This is the heart of your packet.

Step 5: Adjust for differences. If a comp is 200 square feet bigger than yours, its raw price per square foot understates what yours should sell for. Note the significant differences and adjust your requested value. You don't need an appraiser's precision. A documented, reasonable adjustment is enough.

Step 6: Fill out the appeal form. Find it on your county assessor or board of review website. State your parcel number, current assessed value, requested value, and attach your comp grid plus any photos.

Step 7: File before the deadline. File online if the county allows it. Keep a confirmation email or paper receipt. Note the hearing date.

Step 8: Prepare a two-minute presentation. One sentence on your property, one sentence on your method, and a verbal walk-through of your comp grid. Practice the price-per-square-foot comparison out loud.

Step 9: Attend the hearing. Show up on time. Stay calm. If the board offers a settlement before the hearing starts, weigh it against your comp evidence. You're not obligated to accept.

TaxFightBack's DIY appeal kit packages steps 4 through 6 into a fillable template, which saves you time on formatting. Every one of these steps is doable with nothing but a spreadsheet and a printer.

Frequently asked questions

How long does a DIY property tax appeal take from start to finish?

Gathering evidence and filing takes most homeowners two to four hours. The wait between filing and your hearing runs from a few weeks to six months depending on the county. The hearing itself is usually 10 to 15 minutes. Total time invested is realistically five to seven hours for a residential appeal, roughly what a firm's intake process would take from your end anyway.

Do I need a licensed appraiser to appeal my property taxes?

No. For informal board hearings, where most residential appeals get decided, comparable sales data pulled from public records is enough. A licensed appraisal ($300 to $500 for a single-family home) can strengthen a borderline case or a formal appeal, but it's overkill for the typical protest. Your county's own sales database covers most cases.

What percentage of property tax appeals are successful?

Success rates vary widely by jurisdiction. Research by the Lincoln Institute of Land Policy found that owners who appeal win reductions roughly 40 to 70 percent of the time, depending on how aggressively the local assessor sets values and how active the local appeal culture is. Filing only when your comps clearly support a lower value puts you in the favorable end of that range.

Can a contingency firm guarantee they'll lower my taxes?

No firm can guarantee a reduction. The contingency structure aligns incentives: the firm gets paid only if it wins. That's useful for you, but it also means firms take only cases with obvious potential. If a firm declines your case, that tells you something. If comps strongly support a lower value, file yourself regardless of what a firm says.

What is a good contingency fee percentage for a property tax firm?

For residential properties, 25 to 33 percent of first-year savings is reasonable. Anything above 40 percent for a straightforward single-family case is high. Some firms also charge a flat administrative filing fee of $50 to $150 on top of the contingency, which you should negotiate away or factor into your comparison with DIY.

How do I find comparable sales without access to the MLS?

The county recorder's or assessor's office publishes deed transfer records, which show sale prices. Redfin and Zillow pull from those same public records and let you filter by sale date, bedroom count, and square footage. For most residential appeals these free sources give you enough comps. The MLS adds detail on days on market and listing history, useful but not required for a board hearing.

What is unequal appraisal and how is it different from overvaluation?

Overvaluation means your assessed value sits above what your property would sell for. Unequal appraisal means the assessor applied a higher effective ratio to your property than to similar ones nearby, even if the absolute value is defensible. Texas Tax Code Section 42.26 is one of the clearest statutory versions of this right. Many states have equivalent provisions. You can argue both theories in the same appeal.

What happens if I miss the property tax appeal deadline?

In most states, missing the deadline means you can't appeal that assessment year. You typically wait until the next notice, which may be one to three years away. A handful of states allow late petitions for good cause (illness, mail failure), but those are granted rarely and inconsistently. Set a calendar reminder the day your assessment notice arrives.

Will appealing my property taxes trigger a higher assessment?

This fear has little basis. Assessors don't raise values in retaliation for appeals; that's prohibited in every state. In the rare case where the board's review shows the property was actually undervalued, some jurisdictions allow the assessor to raise the value, but that almost never happens in residential cases when you've filed with solid comp evidence.

How do property tax firms get paid if I don't save anything?

They don't. That's the definition of a contingency arrangement. If the appeal produces no reduction, the firm collects nothing. So firms are highly selective about which cases they take, turning down appeals with weak evidence. If a firm takes your case, it believes a real reduction is available. That selectivity is useful information for your own DIY decision.

Does a property tax reduction stay in effect after the first year?

Usually yes, for the rest of the assessment cycle. Most jurisdictions reassess every one to four years. A successful appeal resets your base value, so savings compound until the next reassessment. Some states, like California under Proposition 13, work differently: assessed value grows at a capped rate from the purchase price, so the appeal mechanics differ from states that reassess annually at market value.

Is the DIY appeal process different for commercial properties?

Meaningfully yes. Commercial values are based more on income potential than comparable sales. Appraisers use cap rates, net operating income, and expense ratios, concepts that take real estate finance knowledge to apply correctly. For commercial properties above roughly $1 to $2 million, the analysis justifies professional help. For a small commercial property like a single-unit rental, the residential sales approach can still work.

What evidence does the assessor's office have that I can request?

Under most state public records laws, you can request the assessor's appraisal file for your property, including the comparable sales used to set your value, the cost schedules applied, and any field inspection notes. Knowing exactly what the assessor relied on lets you attack the weakest comps directly, a more targeted strategy than presenting your own evidence cold.

Sources

1. National Taxpayers Union Foundation, Property Tax Relief Resources: Contingency arrangements for residential property tax appeals typically run between 25 and 50 percent of first-year tax savings
2. International Association of Assessing Officers, Standard on Mass Appraisal of Real Property: Assessors maintain property record cards listing square footage, construction quality, and improvements; errors in these records are valid grounds for appeal
3. Lincoln Institute of Land Policy, Significant Features of the Property Tax: States set statutory assessment ratios that determine the fraction of market value at which property is officially assessed; ratios vary significantly by state
4. Cook County Assessor's Office, Appeals Information: Cook County publishes a comparable sales tool for homeowners and reports data on self-filed versus firm-filed residential appeal outcomes
5. Texas Comptroller of Public Accounts, Property Tax Assistance Division, Appraisal Review Board Process: Texas Tax Code Section 42.26 provides a remedy for unequal appraisal; ARB hearings are designed to be accessible to unrepresented property owners
6. New York City Tax Commission, Application for Correction Deadlines: New York City's application deadline for most properties is March 15 for the following fiscal year
7. Lincoln Institute of Land Policy, Property Tax Appeals Research: Property owners who appeal their assessments succeed in obtaining reductions roughly 40 to 70 percent of the time across jurisdictions
8. California State Board of Equalization, Assessment Appeals Manual: County assessment appeal boards are designed to hear cases from unrepresented property owners; formal rules of evidence do not apply at most informal hearings
9. Illinois Department of Revenue, Property Tax Assessment and Appeals: Illinois property owners must file board of review appeals within 30 days of the assessment notice publication date
10. Texas Comptroller of Public Accounts, Texas Property Tax Code Section 42.26: A property is appraised unequally if the appraised value exceeds the median appraised value of a reasonable number of comparable properties appropriately adjusted
11. Maryland Department of Assessments and Taxation: Maryland publishes assessment records, appeal forms, and sales data through state and county online portals accessible to homeowners