Nassau and Suffolk Run Their Property Tax Grievances on Two Different Clocks
*If you own a home on Long Island, the window to challenge your assessment is short, and it does not open or close on the same day in Nassau as it does in Suffolk.*
Most new buyers assume property taxes are just a number you accept. They are not. Every year you get a chance to argue that your home is assessed too high, and if you win, your tax bill goes down for years. But you have to catch the window, and Nassau and Suffolk run on completely different calendars.
Nassau runs in the winter
Nassau County releases its tentative assessment roll on January 2, and that roll sets the numbers that determine your tax bill two years out. In 2026, the county pushed the filing deadline for grievances to March 31, later than the traditional early March cutoff, after demand for extensions grew. You file with the Assessment Review Commission, known as the ARC, and if you are not happy with what they decide, you can take the case further to Small Claims Assessment Review, called SCAR, which requires a petition and a thirty dollar filing fee.
A reduction you win this cycle does not usually show up as a refund check. Instead it gets baked into the final tax roll for the following year, so the savings arrive gradually on your regular bill rather than all at once.
Suffolk runs in the spring, and the window is tight
Suffolk works on a completely different rhythm. Each of the ten towns, from Babylon to Southold, sets its own tentative roll, but every single one shares the same statutory deadline: the third Tuesday in May. In 2026 that fell on May 19. The filing period only opens around May 1, which leaves homeowners roughly thirteen business days to pull together evidence and get a complete grievance filed.
There is no extension and no late filing in Suffolk. Miss the date and you wait until the following May to try again. Most Suffolk grievances get only a brief look at the town level before being denied, which pushes many homeowners toward a SCAR court petition once the final assessment roll is published later in the summer. One town breaks from the pack on that follow up step. In Huntington, the SCAR filing window runs from September 15 to October 15, not July like the other nine towns, which matters for anyone in Northport, Commack, Dix Hills, or the rest of that town.
Winning a grievance in either county comes down to evidence. You generally need sales records of comparable homes from the past three years to show your home is valued above where the market actually puts it, or records showing your neighbors with similar homes are assessed lower than you.
Both counties' 2026 windows have already closed. But if you just bought a home, or you have never grieved your assessment before, mark your calendar now. Nassau typically opens filings on January 2 and closes in early spring. Suffolk opens May 1 and slams shut the third Tuesday of that same month. Missing either one means paying a bill you might not have had to pay at all.
If you want a read on what your specific assessment looks like against nearby sales, drop a question at /askmuds or check your numbers at /my-home-value/.