The DeVito Team · Keller Williams Realty Greater Nassau
The deadline, how to file yourself, what evidence counts, and what happens next.
Deadline: The next Nassau County filing period runs from January 4, 2027 to March 1, 2027, to appeal the 2028/29 assessment. ARC does not grant extensions.
Cost: nothing to file. You can file on your own, without a lawyer or a grievance firm.
Source: Nassau County Assessment Review Commission calendar. Checked October 30, 2026.
A tax grievance is a request to lower your property's assessment, the value the assessor places on it. It does not challenge the tax rates. Your share of the school, town and county taxes is figured from that assessment, so if the assessment is higher than it should be, a successful grievance lowers your bill. In Nassau County you file with the county's Assessment Review Commission (ARC).
| Assessment | ARC filing period | Status |
|---|---|---|
| 2027/28 | Jan 2, 2026 – Mar 2, 2026 | Closed |
| 2028/29 | Jan 4, 2027 – Mar 1, 2027 | Next |
Watch the year label. Nassau names each cycle by the tax year it sets, which begins more than a year after you file. The appeal you file in early 2027 is for the 2028/29 assessment. Nassau publishes the tentative roll, based on value as of that date, on the day the filing period opens. ARC grants no extensions.
Filed in the 2026 period (2027/28)? ARC's determinations are due by March 31, 2027, the final roll is published April 1, 2027, and the last day to file for Small Claims Assessment Review is April 30, 2027.
Source: ARC calendar, AROW, ARC FAQ. Checked October 30, 2026.
The State Tax Department recognizes four grounds: an assessment that is excessive (higher than the home's market value), unequal (assessed at a higher level than other property), unlawful, or misclassified. Most homeowners argue the first. For that, the State says the best support is sales of comparable homes that sold for less than the assessor's estimate of your home's market value. You must show the board that your property is over-assessed.
Source: NYS Tax Department, completing your grievance; contesting your assessment.
From 2013 to 2025, the median annual tax on Nassau County homes sold went from about $10,900 to about $13,800 (+27%), while the median sale price went from $425,000 to $825,000 (+94%). So tax as a share of price fell, from 2.56% to 1.67%. These are medians across all recorded sales, not any one owner's bill; a grievance turns on your own home's value against the assessor's figure.
| Year | Median tax | Median price | Tax ÷ price | Sales |
|---|---|---|---|---|
| 2013 | $10,900 | $425,000 | 2.56% | 9,332 |
| 2014 | $11,200 | $431,000 | 2.59% | 9,055 |
| 2015 | $11,500 | $445,000 | 2.58% | 9,993 |
| 2016 | $11,700 | $469,500 | 2.50% | 10,879 |
| 2017 | $12,100 | $500,000 | 2.42% | 10,897 |
| 2018 | $12,300 | $525,000 | 2.34% | 10,897 |
| 2019 | $12,500 | $539,000 | 2.32% | 11,269 |
| 2020 | $13,200 | $579,000 | 2.28% | 11,140 |
| 2021 | $13,600 | $650,000 | 2.09% | — |
| 2022 | $13,400 | $690,000 | 1.94% | 11,627 |
| 2023 | $13,300 | $705,000 | 1.89% | 9,070 |
| 2024 | $13,700 | $775,000 | 1.76% | 8,779 |
| 2025 | $13,800 | $825,000 | 1.67% | 8,833 |
Median of each full calendar year's recorded Nassau County closings that report an annual tax (MLS records). Taxes are as recorded at the time of sale. Year 2021 omitted: the MLS record for Nassau County is materially incomplete that year, so a count for it would understate it. Medians for that year are unaffected and are shown where used.
Where prices are heading now. An assessment is an estimate of market value, so the direction of sale prices is the backdrop for any grievance. The monthly median sale price in Nassau County averaged about $860,000 for Jul 2026–Sep 2026 (3,090 sales), against $831,000 for the same months a year earlier (+3%).
| Month | Median sale price | Sales |
|---|---|---|
| Oct 2025 | $820,000 | 964 |
| Nov 2025 | $810,000 | 771 |
| Dec 2025 | $810,000 | 869 |
| Jan 2026 | $825,000 | 767 |
| Feb 2026 | $821,000 | 623 |
| Mar 2026 | $793,500 | 666 |
| Apr 2026 | $825,000 | 627 |
| May 2026 | $849,500 | 736 |
| Jun 2026 | $850,000 | 903 |
| Jul 2026 | $861,000 | 1,078 |
| Aug 2026 | $880,000 | 1,080 |
| Sep 2026 | $840,000 | 932 |
Closed sales recorded in the MLS, all home types. A county-wide median moves with the mix of homes that sold each month.
District-by-district tax figures: Nassau County property taxes by school district.
You do not need anyone's help to grieve. Nassau County says there is no fee to file with ARC and you are not required to have a lawyer or other representative. Some owners prefer to hire a representative, such as a grievance firm or an attorney, to prepare and file for them. If you do, read the agreement before you sign: how the fee is figured, which tax years it covers, and whether it renews on its own.
The annual tax is shown on listings, and buyers weigh it alongside the price. If your assessment looks high, check the grievance calendar before you list, and tell the attorney handling your sale about any appeal that is still pending.
The next Nassau County filing period runs from January 4, 2027 to March 1, 2027, to appeal the 2028/29 assessment. ARC does not grant extensions. Filing is with the Nassau County Assessment Review Commission (ARC), online through AROW or on paper.
File an appeal with the Assessment Review Commission during the filing period, online through AROW (Assessment Review on the Web) or on paper. A one, two or three family house uses form AR1. The application asks for basic information about the property and your own estimate of its market value. Anyone who pays taxes on the property may appeal.
No. Nassau County says there is no fee to file with ARC, and you are not required to use a lawyer or other representative. The only fee in the process comes later, if you take an ARC decision to Small Claims Assessment Review: the State filing fee is $30.
ARC reviews appeals after the filing period closes. Nassau County says final determinations are issued by March 31 of the following year, and the changes appear on the final assessment roll published at the start of April.
A homeowner can ask for Small Claims Assessment Review (SCAR), a low-cost court review with a $30 State filing fee. For the 2027/28 roll, Nassau County lists April 30, 2027 as the last day to file for judicial review, including SCAR. You must have filed with ARC first.
No. A grievance challenges the assessment, the value placed on your property, not the tax rates. Assessors do not set taxes; the rates come from the school district, town, county and other taxing bodies. A lower assessment lowers your share of the tax.
The State Tax Department says that for most homeowners the best support is sales of comparable homes that sold for less than the assessor's estimate of your home's market value. Start by finding the market value the assessor has placed on your home, then compare it with recent sales of similar homes nearby.
No. STAR and other exemptions have their own applications. A grievance challenges the assessment itself, though it can also argue that an exemption was applied incorrectly.
Sources: Nassau County ARC calendar, AROW, how to appeal, ARC FAQ; NYS Tax Department, grievance procedures, completing your grievance; STAR. Checked October 30, 2026.
Joseph DeVito is a New York Licensed Associate Real Estate Broker and a New York attorney. He does not act as both broker and attorney on the same transaction: here he acts as a real estate broker only, and he is not your attorney. Real estate services provided through Keller Williams Realty Greater Nassau are not legal representation. Everything on this site is general information for educational purposes only. It is not legal advice, it creates no attorney-client relationship, and it should not be relied on as legal advice — for advice about your own situation, consult your own attorney.
This page is general information about the assessment review process, not legal or tax advice for your property. Deadlines are set by the county and the towns and can change; confirm the current dates on the official calendar before you file.
The other Long Island county: Suffolk County tax grievance.
The DeVito Team of Keller Williams Realty Greater Nassau
Joseph DeVito, NY Licensed Associate Real Estate Broker
400 Garden City Plaza Ste 438, Garden City, NY 11530 · (516) 770-3782
