Last updated 2026-07-09
TL;DR
Fairfax County assesses residential property at 100% of estimated fair market value every January 1, mails notices in late February, and sets the appeal deadline at April 1. You can appeal online, by mail, or in person to the Department of Tax Administration. If the DTA says no, a second-level Board of Equalization appeal is open. Winning appeals run on comparable sales, not opinion.
How does Fairfax County calculate your assessed value?
Fairfax County assesses all real property at 100% of fair market value as of January 1 each year, because Virginia law requires it [1]. This is not a soft target. Code of Virginia Section 58.1-3201 reads: "All real estate, except that exempted by law, shall be assessed for taxation at its fair market value" [1]. The county takes that at face value.
The Department of Tax Administration uses mass appraisal, not a walk-through of every house. Assessors split the county into neighborhoods, study the prior year's sales, and run statistical models to estimate what your property would have sold for on January 1 [2]. The model leans on sales of homes like yours in size, age, condition, and location, then gets tuned to fit your neighborhood.
The inputs that drive your number are lot size, gross living area, year built, quality grade, and condition rating. The county also tracks building permits, so that deck you added in 2022 probably showed up in your 2023 assessment. They will not step inside your home unless you invite them during an appeal.
Fairfax reassesses every year. Many Virginia localities reassess every two or four years instead. Annual reassessment means your value moves with the market each January, which cuts against you when prices climb and helps you when they fall.
When does Fairfax County mail assessment notices?
The county mails residential assessment notices in late February, usually the third or fourth week [2]. You can also pull your value from the county's online property search any time of year. The January 1 effective date is what counts legally, but the new number does not become real to you until the notice lands.
No notice in your mailbox? Do not assume your value held steady. Look it up. The county treats a missing notice as no excuse for a blown deadline, and Virginia courts have generally sided with the county on that.
The 2024 average residential assessment in Fairfax County rose roughly 6.7% over 2023, per the county's assessment release [2]. That came on top of a 6.97% average increase for 2023. Those are countywide averages. Your house may have moved a lot more or a lot less, depending on what sold near you.
What is the appeal deadline for Fairfax County property tax assessments?
The first-level appeal deadline is April 1 of the tax year [3]. Miss it and you lose the right to challenge that year's value. There is no hardship extension.
Here is the full appeal timeline in one place:
| Stage | Who decides | Deadline |
|---|---|---|
| Administrative appeal (Department of Tax Administration) | DTA staff assessor | April 1 of the tax year |
| Board of Equalization | Independent BOE | 3 years from the last day to file a 1st-level appeal (Va. Code 58.1-3379) |
| Circuit Court | Judge | 3 years from the assessment year (Va. Code 58.1-3984) |
April 1 catches people off guard because it lands only about five or six weeks after notices arrive. Get your notice on February 20 and you have roughly 39 days to pull comps, build your case, and file. Do not wait until March 31.
Commercial property runs on the same April 1 administrative deadline. Large commercial owners often jump straight to the Board of Equalization, because the BOE can compel a fuller, discovery-style exchange of evidence.
How do you appeal your Fairfax County assessed value?
You can file a first-level appeal three ways: online through the county's portal, by mailing a written appeal to the Department of Tax Administration, or in person at the Fairfax County Government Center [3]. The online portal is the path of least resistance. You fill out a short form, upload your documents, and get a confirmation number.
Your appeal should include:
- At least three comparable sales that closed near January 1 of the tax year
- The sale price, sale date, address, square footage, year built, and lot size for each comp
- A note on how each comp differs from your home (smaller kitchen, older roof, busy road)
- Your property record card showing the characteristics the county has on file
- Photos if the county's records are wrong (bedroom count, a basement listed as finished that is not)
After you file, a DTA assessor reviews your evidence and either sets up a phone or in-person conference or mails a decision. A first-level decision usually takes 30 to 60 days, though no statute forces the county to answer on a clock.
Deny you, or cut the value less than you think is fair? You can escalate to the Board of Equalization. The BOE is a panel of citizens appointed by the Fairfax County Circuit Court. That hearing runs more formally. You present your case, the county's assessor presents theirs, and the board decides. No lawyer required, but the process rewards preparation.
Want a guided way to build your comp set and write the letter? The TaxFightBack appeal kit walks through the Fairfax-specific evidence format step by step.
What evidence actually wins a Fairfax County appeal?
Comparable sales are the only evidence that moves the needle consistently. Your opinion that the house is worth less, a Zillow estimate, a neighbor's story about falling prices: none of it gets far. The assessor hears those every day and sets them aside.
A strong comp set is three to six homes that sold within roughly six months of January 1, within a mile or two of your property, with similar square footage (within 10 to 15%), age, and condition. Pull them from the county's property search, Zillow, Redfin, or Bright MLS public records. The county's own sales data is searchable for free [4].
Adjustments matter. If your best comp is 200 square feet larger than your home, its raw sale price overstates your value. Apply a per-square-foot adjustment. Fairfax assessors tend to value gross living area somewhere between $150 and $350 per square foot depending on the neighborhood, but the right number comes from your neighborhood's own sales, not a rule of thumb.
Condition evidence carries weight too. A 25-year-old roof, an original HVAC system, documented water intrusion: those are real value adjustments. Get contractor estimates or an inspection report in writing. A $20,000 roof replacement quote is a value difference the assessor has to address.
One argument that never works: my tax bill is too high because I am on a fixed income, or because the assessment jumped. Real problems, wrong venue. The appeal tests one thing only, whether the assessed value matches market value on January 1. The affordability side belongs to the tax relief programs below.
What exemptions and tax relief programs does Fairfax County offer?
The county runs several programs that can shrink or wipe out your tax bill no matter what your assessed value is [5].
The Tax Relief for the Elderly and Disabled program is the big one. Homeowners who are 65 or older, or permanently and totally disabled, and who fall under the income and net worth limits, can get full or partial exemption. For the 2024 tax year the income limit is $90,000 and the net worth limit is $400,000, not counting the value of the primary home [5]. It is not automatic. Apply by May 1.
The surviving spouse of a service member killed in action can get a full property tax exemption under Virginia Code 58.1-3219.9, with no income or asset test [6].
A veteran with a 100% service-connected disability rating gets a full exemption on one home under Virginia Code 58.1-3219.5 [6]. It does not trigger on its own. You have to apply.
The Land Use Program lets owners of agricultural, horticultural, forest, or open-space land pay taxes on use value instead of market value [7]. On large parcels the savings can be big. The application deadline is November 1 of the year before the tax year.
| Program | Who qualifies | Key limit | Deadline |
|---|---|---|---|
| Elderly/Disabled Relief | Age 65+ or disabled, owner-occupied | Income ≤ $90,000; net worth ≤ $400,000 | May 1 |
| Disabled Veteran | 100% service-connected | None (income/asset) | None stated, apply promptly |
| Surviving Spouse (KIA) | Spouse of killed-in-action military | None | None stated |
| Land Use | Agricultural/forest/open space | Bona fide use | November 1 |
These programs stand apart from the assessment appeal. You can pursue both.
How does Fairfax County's assessment compare to your home's market value?
The county aims for a ratio of assessed value to market value (the sales ratio) as close to 100% as it can hit [2]. The Virginia Department of Taxation tracks that ratio every year through its assessment/sales ratio study. Fairfax County has historically landed in roughly the 95% to 102% range, so assessments track actual sale prices closely at the neighborhood level.
"Close at the neighborhood level" does not mean close for your house. Mass appraisal models carry standard errors. Individual properties can sit well off the aggregate ratio even in a well-run county, which is exactly where an appeal lives.
A recent purchase is your best card. If you just bought and the assessment already tops what you paid, that is strong evidence. An arm's-length sale is generally the cleanest measure of market value, and Virginia courts have recognized this repeatedly. Buy in August, then get assessed 15% higher the following January 1, and you have a real case.
The reverse holds too. If you paid well above the assessed value, you probably do not have an appeal worth filing. The assessed value has to exceed fair market value for an appeal to go anywhere.
How do you look up your Fairfax County assessed value online?
The county's Real Estate Assessment database is public and free [4]. Search any residential or commercial property by address, parcel ID (also called a tax map reference number), or owner name. The record shows the current assessed value, prior-year values going back several years, the split between land value and improvement value, and the property characteristics on file.
Pull your own record first, before anything else. Check square footage, bedroom count, bathroom count, and any special features the county recorded. Errors happen more than you would think. A basement marked finished when it is raw, a phantom bathroom, a quality grade set too high: any of those inflates your value. Fixing a factual error through an appeal is often the easiest win on the board.
The county's online portal also lets you file the administrative appeal and upload documents directly [3]. You only need to go to the Government Center if you want an in-person conference.
What happens if you do nothing and just pay the higher tax bill?
You lose the right to challenge that year's value after April 1. Done. The tax bill is assessed value times the tax rate. The Fairfax County Board of Supervisors sets the rate separately (it was $1.095 per $100 of assessed value for calendar year 2024, and the board can adjust it each year) [8]. You cannot touch the rate. The assessed value is the only lever in your hand.
Sit out an appeal and later find a factual error (wrong square footage, wrong lot size), and you can file in a later year, but you cannot claw back taxes overpaid in prior closed years except in narrow fraud or clear clerical-error cases.
The math stacks up quickly. On a $750,000 assessment at $1.095 per $100, your annual tax is $8,212. If the value should be $680,000, the correct tax is $7,446. That is $766 a year in overpayment, roughly $2,300 across three years.
How does Fairfax County treat new construction and recently renovated homes?
New construction gets a partial-year assessment in the year the home is finished and added to the tax rolls. Finish on August 1 and you get assessed for roughly five months of that year on the completed structure, with a full assessment starting the next January 1 [2].
Permitted renovations trigger a reassessment of the affected improvements. Pull a permit for a 400-square-foot addition, get it finaled before January 1, and the county adds that square footage to your record. Final the permit after January 1 and it usually shows up in the next year's assessment.
Unpermitted work is where it gets messy. If the county finds square footage or a finished basement that never ran through a permit, it will add the value and, in some cases, back-assess prior years. Most property tax practitioners give the same advice: pull permits for everything. The compliance cost almost always beats the catch-up assessment exposure.
How does the Fairfax County appeal compare to other major counties?
Appeals run differently in every jurisdiction. In Fairfax County the process is well-documented, fully online-capable, and needs no lawyer at any stage before Circuit Court. Compare that to Cook County in Illinois, where the cook county tax assessor tax bill process starts with a township assessor, moves to a Board of Review, and runs longer and more procedurally.
In Maricopa County, Arizona, maricopa property tax appeals go to the Assessor's office first, then a State Board of Equalization, under different evidence standards. In California, the san diego property tax appeal runs through an Assessment Appeals Board with a formal hearing structure.
Fairfax sits in the middle of the complexity range. More accessible than Illinois or California, more rigorous than many rural Virginia counties. The BOE hearing is a genuine adversarial proceeding where the county's assessor defends the value out loud. Documented comps and condition evidence are not optional at that stage.
Georgia homeowners face a close cousin of this system: the gwinnett county tax assessor and cherokee county tax assessor processes also use 100% fair market value assessment, with different appeal windows and board structures worth comparing.
Should you hire a property tax firm or do it yourself in Fairfax County?
Contingency firms charge 25% to 40% of your first-year tax savings, sometimes across multiple years. On a $766 annual reduction, that is $192 to $306 in fees for your first year alone, if they take just one. Plenty take two.
The DIY case is strong in Fairfax specifically. The county's sales data is public and searchable, the appeal form is short, and the administrative level involves no formal hearing. You are submitting comps and a cover letter, essentially. The DTA assessor reads it, may call with questions, and issues a decision.
A firm earns its fee on commercial property with income-approach valuations, or on BOE and Circuit Court appeals where the county brings an attorney. For a residential owner filing a first-level DTA appeal, the information you need is free and the process is within reach.
The TaxFightBack appeal kit hands you the Fairfax-specific comp worksheet, evidence checklist, and appeal letter template, so you never start from a blank page. You keep 100% of any reduction you win.
Working through your own version of this in another state? The lake county property tax and los angeles county property tax articles cover different DIY appeal contexts worth reading before you decide to go it alone.
What are the most common mistakes Fairfax County homeowners make on appeals?
Missing the April 1 deadline is number one. No exceptions, no sympathy.
Second is filing without comps and hoping the assessor does the research for you. They will not. Under Virginia law the burden of proof sits with the property owner to show the assessed value exceeds fair market value [9]. Bring the evidence yourself.
Third is treating a Zillow Zestimate as a comp. It is not a comparable sale. It is a model's guess. The county will say exactly that and drop it. Use actual closed sales with recorded deeds.
Fourth is appealing a value that is already below market. Buy in 2023 for $850,000, get assessed at $810,000, and an appeal likely produces no change or an increase. Assessors can raise values during an appeal in Virginia, and while DTA staff rarely push that at the first level, the BOE has broader authority.
Fifth is skipping the property record card. Check it for factual errors before you reach for market-value arguments. A wrong square footage or a phantom bathroom in the county's database is a faster, cleaner win than any comp analysis.
Frequently asked questions
What is the Fairfax County property tax appeal deadline?
April 1 of the tax year is the deadline to file a first-level administrative appeal with the Department of Tax Administration. There is no extension for hardship or slow mail. Miss April 1 and your next shot is to wait for the following year's assessment notice and appeal that one.
How do I look up my Fairfax County assessed value?
Use the county's free Real Estate Assessment database through the Department of Tax Administration. Search by address, parcel ID, or owner name. The record shows current and prior-year assessed values, the land-to-improvement split, and the property characteristics on file, including square footage and quality grade.
Can Fairfax County raise my assessment during an appeal?
Yes, legally it can. Virginia gives the Board of Equalization authority to raise, lower, or confirm an assessment. At the first-level DTA stage an increase is rare but possible. If your property looks assessed below market, appealing carries some risk. Most first-level reviews end in a confirmation or a modest reduction, not an increase.
What is the Fairfax County property tax rate for 2024?
The Board of Supervisors set the residential real property tax rate at $1.095 per $100 of assessed value for calendar year 2024. The Board sets this rate annually, and it is separate from your assessed value. Cutting your assessed value is the only part of the equation an appeal can touch.
Do I need a lawyer to appeal my Fairfax County property tax assessment?
No. Homeowners can represent themselves at the DTA administrative level and before the Board of Equalization without a lawyer. Legal representation gets more common at the Circuit Court stage, where formal rules of evidence apply. Most residential appeals never reach Circuit Court.
How often does Fairfax County reassess property?
Annually. Every property gets a new assessed value effective January 1 each year. That differs from many Virginia localities that reassess every two or four years. Annual reassessment means your value tracks the market more closely in both directions.
What is the senior tax relief income limit in Fairfax County?
For the 2024 tax year, the income limit for the Elderly and Disabled Tax Relief program is $90,000 in combined household income. The net worth limit is $400,000, not counting the value of your primary residence. You must be 65 or older, or permanently and totally disabled, and the home must be your primary residence. Apply by May 1.
How much does the average Fairfax County assessment increase per year?
The average residential assessment rose about 6.7% for the 2024 tax year, after a 6.97% increase in 2023, per county assessment releases. Those are countywide averages. Individual properties vary with neighborhood sales activity. Some neighborhoods saw double-digit jumps; others were flat.
Can I appeal if I just bought my Fairfax County home and paid less than the assessed value?
Yes, and this is one of the strongest grounds you can bring. A recent arm's-length sale is generally the best evidence of fair market value under Virginia law. If you closed in mid-2023 and the January 2024 assessment tops your purchase price, bring your settlement statement and purchase contract to the appeal.
What is the difference between the DTA appeal and the Board of Equalization?
The DTA administrative appeal is an informal first step handled by county staff. The Board of Equalization is a formal second step before an independent panel. The BOE can hear new evidence, compel the county to share its evidence, and override the DTA decision. BOE hearings play out like a mini-trial. Most homeowners only need the first level.
Does a recent home sale in Fairfax County trigger a reassessment?
Not automatically mid-year. Virginia uses a January 1 effective date. Buy a home in September and your assessment for that year was already set. Your first assessment under new ownership will be as of the following January 1, reflecting market conditions at that point, including your purchase price.
How do I find comparable sales to support my Fairfax County appeal?
Start with the county's own property search and sales database, which is public and free. Redfin and Zillow both show recent closed sales. Look for homes that sold within six months of January 1 of the tax year, within one to two miles, with similar square footage, age, and condition. Three to six solid comps are enough at the DTA level.
What happens if I win my Fairfax County appeal?
The county reduces your assessed value for that tax year and recalculates your bill. If you already paid on the higher assessment, you get a refund or a credit on your next bill. The reduction applies only to the year you appealed. You will need to watch future assessments and appeal again if the value stays inflated.
Is the Fairfax County assessed value the same as appraised value for a mortgage?
No. The county's assessed value is a mass-appraisal estimate for tax purposes. A mortgage appraisal is an individual appraisal by a licensed appraiser using a method lenders require. The two numbers often differ. A mortgage appraisal is useful appeal evidence, but it was not built for tax purposes, so the county may scrutinize its comps.
Sources
- Virginia Legislative Information System, Code of Virginia Section 58.1-3201: All real estate in Virginia must be assessed at 100% of fair market value as of January 1 each year
- Fairfax County Department of Tax Administration, Real Estate Assessments overview: Fairfax County reassesses annually, mails notices in late February, and the 2024 average residential assessment increased approximately 6.7% over 2023
- Fairfax County Department of Tax Administration, real estate tax and appeals information: First-level administrative appeals must be filed by April 1 of the tax year; filing can be done online, by mail, or in person
- Fairfax County Department of Tax Administration, Real Estate Assessment Search: The county's Real Estate Assessment database is publicly searchable at no charge by address, parcel ID, or owner name
- Fairfax County Department of Tax Administration, tax relief information: The 2024 income limit for the Elderly and Disabled Tax Relief program is $90,000 and the net worth limit is $400,000 excluding the primary residence; application deadline is May 1
- Virginia Legislative Information System, Code of Virginia Section 58.1-3219.5: Virginia exempts one home from property tax for veterans with a 100% service-connected disability rating, and separately for surviving spouses of service members killed in action under 58.1-3219.9
- Virginia Legislative Information System, Code of Virginia Section 58.1-3230 (land use assessment): Land use valuation allows agricultural, horticultural, forest, or open-space landowners to be taxed on use value rather than market value; Fairfax sets a November 1 application deadline
- Fairfax County Board of Supervisors, Adopted Budget: The residential real property tax rate for calendar year 2024 was set at $1.095 per $100 of assessed value
- Virginia Legislative Information System, Code of Virginia Section 58.1-3984: In Virginia, the burden of proof in a property tax appeal is on the taxpayer to show the assessed value exceeds fair market value
- Virginia Legislative Information System, Code of Virginia Section 58.1-3379: Virginia Board of Equalization appeals may be filed within three years of the last day to file a first-level appeal
- Virginia Department of Taxation: The Virginia Department of Taxation monitors assessment-to-sales ratios annually; Fairfax County has historically maintained ratios in the 95% to 102% range