A Nassau County property tax grievance is a formal challenge to the county’s estimate of your home’s market value, filed with the Assessment Review Commission (ARC) between January 2 and the annual deadline. If the ARC agrees your home is worth less than the tentative roll says, your assessed value drops and your tax bill follows. The commission cannot raise your assessment in response to a grievance, so filing carries no risk of a worse outcome.1Hempstead Town, NY. Challenge and Lower Your Taxes
What the ARC Decides
The Department of Assessment publishes a tentative assessment roll each January showing the county’s estimated market value for every parcel. That market value, multiplied by the level of assessment, produces the assessed value that drives your tax bill. A grievance asks the ARC, an independent body, to find that the market value figure is too high.
You file an Application for Correction of Assessment. The ARC reviews it and issues a Notice of Determination that either grants a reduction or denies the complaint. A successful reduction typically flows through to the October school tax bill and the following January general tax bill, and it carries forward until the county reassesses. If you already paid taxes at the higher figure, you are entitled to a refund for the overpayment.
The Filing Deadline
The grievance window opens January 2. The statutory deadline is March 1, but the ARC has repeatedly extended it; for the 2027–2028 tax year, the extended deadline is March 31, 2026.1Hempstead Town, NY. Challenge and Lower Your Taxes Check the ARC website each January for the current year’s cutoff. Miss it and you wait until the next grievance cycle.
The easiest way to file is through AROW, the county’s Assessment Review on the Web portal, which lets you upload documents and gives instant confirmation.2Nassau County, NY. Assessment Review Commission You can also mail the application to the Assessment Review Commission at 240 Old Country Road, 5th Floor, Mineola, NY 11501. If you mail it, use certified mail and make sure the postmark lands before the deadline.
To file, you need your Section, Block, and Lot number, which appears on your tax bill.
Evidence That Wins a Reduction
The core of a residential grievance is comparable sales: recent transactions involving similar homes in your neighborhood that sold for less than the county’s estimated market value of your home. The state identifies comparable sales as the best way to support a residential grievance, without setting a required number.3New York State Department of Taxation and Finance. Completing the Grievance Form Three to five strong comparables from the same area generally make a persuasive case. A professional appraisal from a licensed residential appraiser adds weight when the comparables are not clean.
Two technical points catch people off guard. Your grievance must be based on the total assessed value of the entire parcel, land and building together; you cannot challenge land or building separately.3New York State Department of Taxation and Finance. Completing the Grievance Form And be deliberate about the reduction amount you request. State guidance warns that you may be prevented from receiving a larger reduction than you asked for, even if your evidence would have supported one. Ask for what your comparables actually show.
Filing Yourself vs. Hiring a Grievance Firm
You can file the application yourself or designate a representative or attorney to file on your behalf.3New York State Department of Taxation and Finance. Completing the Grievance Form Grievance firms are common in Nassau County and usually work on contingency, taking a percentage of your first year’s tax savings only if they win a reduction. Fifty percent of the first year’s savings is a common fee, with variation by firm.
Self-filing works well when the evidence is obvious: a near-identical house down the block sold recently for well under your assessed market value, and the AROW form takes an evening. A firm is worth considering when the comparables are mixed, your property has unusual features that complicate valuation, or you simply don’t want to assemble the file. The quality of the comparable sales matters more than who submits them.
If the ARC Denies You or Offers Too Little
An unfavorable ARC decision is not the end. For owner-occupied one-, two-, or three-family homes used exclusively as residences, and for residential lots too small to build such a home, the next step is Small Claims Assessment Review (SCAR), a court-supervised process under Real Property Tax Law Section 730.4New York State Senate. Real Property Tax Code 730 – Procedure to Review Small Claims
A SCAR petition is filed with the Nassau County Clerk within 30 days of the filing of the final assessment roll. Nassau County towns must file that final roll no later than April 1, so the SCAR window typically closes around May 1.5New York State Unified Court System. Small Claims Assessment Review General Petition Instructions The filing fee is $30 per parcel, and each petition covers only one parcel.4New York State Senate. Real Property Tax Code 730 – Procedure to Review Small Claims A hearing officer reviews the evidence and issues a binding decision for that tax year. SCAR is designed to work without an attorney. Hearing officers use the Residential Assessment Ratio, a statewide figure comparing assessed values to full market values in each municipality, to judge whether a home is unequally assessed relative to its neighbors.6New York State Department of Taxation and Finance. Residential Assessment Ratios
Owners whose properties don’t qualify for SCAR, or who want to skip it, can file an Article 7 tax certiorari proceeding in Supreme Court. This is a full legal proceeding, usually requiring an attorney, and the economics rarely justify it for a single-family home; most Article 7 cases involve commercial property.7New York State Department of Taxation and Finance. Understanding Real Property Tax Assessment Review Proceedings For most Nassau homeowners, ARC followed by SCAR if needed is the practical path.
Incorporated Villages File Separately
Some incorporated villages in Nassau County keep their own assessment rolls for village taxes. If you live in one, a successful ARC grievance will lower your county and school taxes but will not touch your village tax bill; a separate challenge with the village assessor is required to address that piece.8Town of North Hempstead, NY. Grievances and Assessment Ask your village clerk whether your village uses the county roll or its own.
Don’t Overlook Exemptions
A grievance challenges what the county thinks your home is worth. Exemptions reduce the taxable portion of that value and run on a separate track. STAR, Enhanced STAR for homeowners 65 and older, the Alternative Veterans and Cold War Veterans exemptions, the Senior Citizens exemption, the exemption for persons with disabilities and limited incomes, and the volunteer firefighters and ambulance workers exemption are all filed with the Department of Assessment rather than the ARC, and they can stack on top of a successful grievance. If you have not reviewed your exemptions recently, do that alongside your grievance filing rather than instead of it.