Property Tax Grievance: What You Need to Know
A property tax grievance lets New York homeowners challenge their assessed value and potentially lower their tax bill. This guide covers who can file, the forms you'll need, and county-specific deadlines for Nassau, Suffolk, Westchester, and NYC.
In Nassau County, the median home is worth $518,000, and the typical owner pays $3,634 a year. That reflects an effective property tax rate of 0.71% in Ownwell's Nassau County market data.
In New York, local communities and municipalities annually assess the value of your property to establish property taxes for the next two years. For instance, in Nassau County, the valuation date for the 2027 and 2028 tax years is January 1, 2026.
However, you don't have to accept the valuation prepared by your municipality's annual assessment roll, the list of taxable property in a community and its taxable assessed value.
You can, and should, contest your county's tax assessment via a property tax grievance.
Key Takeaways
A property tax grievance is New York's formal process for challenging your assessed value and lowering your tax bill.
Filing a grievance asks the review body to lower or confirm your assessment, so it won't raise what you owe.
Deadlines and forms differ by county across Nassau, Suffolk, Westchester, and New York City.
You can grieve every year, and comparable sales near the July 1 valuation date are what win cases.
What Is a Property Tax Grievance?
A property tax grievance is New York's formal process for challenging the assessed value of your property. Other states call this an "appeal," "protest," or "petition," but in New York, "grievance" is the legal term.
The deadline to file with your assessing unit is known as Grievance Day, the date the review body begins hearing challenges for the year.
Your annual property tax bill is calculated using this formula:
Assessed Value ÷ 1,000 × Tax Rate = Property Tax
For example, if your assessed value is $1,000,000 and the tax rate is $25 per $1,000, your property tax would be $25,000.
Here's how a successful grievance changes the math for a Nassau homeowner:
Scenario | Taxable Market Value | Effective Tax Rate | Annual Tax Bill |
|---|---|---|---|
Before grievance | $750,000 | 0.71% | $5,325 |
After a 10% reduction | $675,000 | 0.71% | $4,793 |
That 10% reduction cuts the bill by $533 a year, savings you keep for every year the lower value holds.
Why File a Tax Grievance?
Even if you don't think your current assessment is too high, it's worth filing.
Filing a grievance can lower your tax bill. It lets you challenge an inflated valuation and reduce what you owe the county.
By addressing over-taxation, you make sure you're not paying more than your fair share.
Other Benefits of Filing a Grievance
Challenge inflated assessments: Compare your market value against the assessed value to spot overvaluation.
Prevent overpayment: Keep your tax bill aligned with your property's actual value.
Stack with exemptions: A grievance can pair with the Basic STAR Exemption and other property tax exemptions like senior, veteran, and disability.
No downside risk: In Nassau, the Assessment Review Commission will never increase your assessment, so filing carries no downside risk.
Note: You can only grieve the current assessment. Previous tax years cannot be grieved.
How Much Are You Over Paying?
Who Can File a Property Tax Grievance?
In New York, property owners, purchasers, and tenants required to pay property taxes due to a written or lease agreement can file a tax grievance.
In New York City and Nassau County, the following property types are eligible to file a grievance:
One, two, or three-family residential parcels
Residential condominiums
Mobile homes and trailers, if they're owner-occupied and assessed individually
Mixed-use parcels (used in part for residential and non-residential purposes), but only if the primary use is residential, e.g., a small law office connected to your home.
Vacant lands and parcels, not exceeding 10 acres, that are within an assessing unit that has an ordinance or zoning law in effect. The zone must not allow residential use outside of one-, two-, or three-family dwellings.
Farm dwellings
Land used in agricultural production that's eligible for an agricultural assessment and has completed its annual application (See Sections 305 and 306 of the Agriculture and Market Law)
Farm buildings and structures (Defined in Section 483(3) of the Real Property Tax Law)
What Are Valid Grounds for a Grievance?
New York recognizes three main grounds for a property tax grievance. Your case must fit at least one of them.
Excessive assessment (overvaluation): Your assessed value is higher than your property's actual market value.
Unequal assessment: Your property is assessed at a higher ratio than comparable homes nearby.
Unlawful assessment or misclassification: Your property is taxed in error or placed in the wrong tax class.
Winning cases rest on evidence. The strongest is comparable sales as of the July 1 valuation date that show your home is worth less than its assessed value.
At Ownwell, we build your case from those comparable sales and market data, then present it through the grievance process. See how our property tax grievance service assembles the evidence for you.
How to File a Tax Grievance
Filing a property tax grievance varies by county and municipality. The processes are similar across New York, but deadlines and forms differ. Check your local government website for specifics.
If this feels overwhelming, Ownwell can handle your grievance. Signing up takes a few minutes; there are no upfront costs, and you only pay if you save.
Most New York counties use mass appraisal models: comparable sales for residential properties and income models for commercial properties. Counties and towns also split taxes into two categories: school taxes and general taxes.
For a step-by-step walkthrough, see our complete Nassau County grievance filing process.
Once you receive your tentative assessment roll, you have only a few months to file an informal property tax grievance form. Depending on the county, you file either an AR-1 Form, RP-524 (3/09), or TC form to the Assessment Review Commission (ARC) or the Board of Assessment Review (BAR).
County | Assessment Roll Date | Form Used | Filing Body |
|---|---|---|---|
Nassau County | January 2 | ARC | |
Suffolk County | May 1 | BAR | |
Westchester (towns/cities) | June 1 | BAR | |
New York City | January 15 | Tax Commission |
New York City residents must file their TC forms in person or via mail by:
March 15, 2026 (Class 1 properties)
March 1, 2026 (Class 2 and 4 properties)
Visit NYC.gov's tax class breakdown if you're unsure which class you fall into.
In other counties, like Suffolk or Westchester, you'll appear before a BAR.
Remember, the initial filing is an informal grievance. If your grievance isn't resolved at that stage, here's what happens next:
Nassau County: The ARC and owner exchange two or three offers. A rejected final offer moves the case to Small Claims Assessment Review (SCAR).
Suffolk and Westchester: You submit evidence to the BAR. If you disagree with the decision, you can escalate to SCAR.
Come prepared with documentation: recent comparable sales, a recent appraisal, or your purchase price if you bought recently.
SCAR hearings require a $30 filing fee. You or your property tax consultant will present evidence before a hearing officer. Commercial properties typically require an attorney to attend.
In Nassau, SCAR hearings are scheduled by the court in the months after the filing period closes. We haven't received exact court dates for Suffolk or Westchester yet.
If you win your SCAR hearing, you receive a refund for the overpaid taxes, which in Nassau the County is responsible for paying.
Nassau County Tax Grievance Timeline (2026/27 Tax Cycle)
Nassau has one of the more straightforward timelines when it comes to property tax payments and grievance due dates. In other counties, such as Westchester, the local town or city determines these dates.
To give you an idea of how property taxes in New York work and to notify you of significant dates, here's Nassau County's property tax timeline:
2025/26 Notable Dates & Deadlines
January 2, 2025: The tentative assessment roll was released
This roll is used for the 2026/26 School and 2026 General taxes.
January 1, 2025: Deadline to file for Nassau County property tax exemptions.
January 1-March 31, 2025: Grievance period to examine the assessment and file your AR-1 Form with the ARC.
Note: The original deadline was March 1, but it was extended to the 31st for the 2025/26 cycle.
April 1, 2025: Extended deadline to file 2025/6 Nassau County tax grievance
April 30, 2025: Deadline for filing 2025/26 SCAR petitions.
July 1, 2025: Valuation date (for the subsequent roll for 2026/27).
Note: The valuation date for the 2025/26 roll was July 1, 2024
November 18, 2025: Village tax grievance deadline for some villages for 2025/26.
2026/27 Notable Dates & Deadlines
January 2, 2026: Tentative Assessment Roll for 2027/28 is published.
January 20, 2026: Deadline to file a grievance for the City of Long Beach for 2026/27.
January 31, 2026: Deadline to file a grievance for Villages for 2026/27.
February 10, 2026: The deadline for the first half of the 2026 General Tax
February 17, 2026: Village tax grievance deadline for most Villages.
March 31, 2026: Extended Nassau County property tax deadline for 2027/28
April 30, 2026: Deadline to file a petition for Nassau County Small Claims Assessment Review (SCAR) for 2027/28.
May 11, 2026: Is the deadline for the second half of the 2026/27 school tax
June 16, 2026: Deadline to file a grievance for the City of Glen Cove.
November 10, 2026: First half of school tax payment due for 2027.
February 10, 2027: First half of the general property tax payment due for 2027.
May 10, 2027: Second half of school tax payment due for 2027/28.
August 10, 2027: Second half of the general property tax payment due for 2027/28.
How Ownwell Can Help
The Nassau grievance process runs on strict deadlines, county forms, and hearings that can stretch across a year. At Ownwell, we handle it all for you.
Our local tax experts file your grievance, build your evidence from comparable sales, negotiate with the ARC, and attend SCAR hearings on your behalf.
You pay nothing upfront. Our 25% contingency pricing means you only pay if we lower your tax bill.
Ownwell customers save an average of $774 a year, and we maintain an 88% success rate across the cases we file. In Nassau County, we win 93% of the time and save homeowners an average of $1,462.
Ready to challenge your assessment? Start your property tax grievance with Ownwell and pay only when you save.
