The Nassau County Assessment Review Commission's 2027/28 filing window closed on March 31, 2026. The next window opens January 2027 for the following tax year. Roughly 386,141 Nassau homeowners are eligible to file each year — here's how the process works so you're ready.
Nassau County reassesses every property every year. Each January, the Assessment Department issues a Tentative Assessed Value for the upcoming tax year. If you think that value is higher than what your house would actually sell for, you can grieve it — formally challenge the number with the Assessment Review Commission (ARC).
Filing a grievance does not change your tax rate. It changes the assessed value your rate is multiplied by. A 10% reduction in assessed value translates to roughly a 10% lower property tax bill — and unlike most exemptions, the savings continue every year unless the County reassesses you back up.
You can file on your own (free, using Form RP-524 or Nassau's online portal) or hire a tax grievance firm. Firms typically charge 50% of the first-year savings on contingency — no savings, no fee.
Nassau's Assessment Review Commission accepts grievances through its online portal (AROW). You file Form AR1 (residential) or AR2 (commercial). Required information:
Filing takes 20-30 minutes. ARC will respond in writing, usually with an offer to settle at a reduced value. If you accept, you sign and you're done. If you reject, you can pursue Small Claims Assessment Review (SCAR) in NY Supreme Court for ~$30.
Firms like Maidenbaum, Heller & Consultants, P.T.R.C., and others handle the entire process. They charge no upfront fee. If they win you a reduction, they take 50% of the first-year tax savings (some advertise 30-40% but verify in writing). If they don't win, you owe nothing.
Trade-off: you save your time and they have established relationships with ARC. Downside: you give up half of year-one savings and you have to share your contact information.
Only worth it for high-value homes ($1.5M+) where the savings justify legal fees. Attorneys handle Small Claims Assessment Review (SCAR, for residences under $450,000 in assessed value) or full tax certiorari proceedings in NY Supreme Court.
| Factor | DIY (file yourself) | Hire a firm |
|---|---|---|
| Upfront cost | $0 | $0 (contingency) |
| If you win | Keep 100% of savings | Keep ~50% of year-1 savings, 100% after that |
| Time investment | 30 min filing + research | 5 min — sign authorization |
| Best for | Tech-comfortable owners with clear comps | Time-constrained owners, complex cases |
| Risk | None — worst case is no reduction | None — no fee if no savings |
Yes. Nassau reassesses every year, so your assessed value can creep up year over year. Filing a grievance is risk-free — ARC cannot increase your value in response. Most Long Island grievance firms recommend filing annually as a maintenance step.
Nassau's historical average for successful grievances is a 5-15% reduction in assessed value, which translates to roughly that same percentage off your tax bill. On the median Nassau home with a $11,036/yr bill, that's $552-$1,655/yr in ongoing savings. Higher-value homes often see larger absolute savings.
No. ARC can only reduce or maintain your assessed value during a grievance review. This is a statutory protection. You face zero risk by filing.
Yes, and you absolutely should. Your purchase price is one of the strongest pieces of evidence available. If you paid less than the assessor's estimated market value, that gap is a direct argument for a reduction.
You have to wait until the next cycle (January 2027) to grieve. There is no late-filing window for Nassau grievances. Mark your calendar for the next cycle and set up a reminder for January.
No. STAR, Senior, Veterans, and other exemptions are separate from your assessed value. Grieving reduces the taxable assessed value those exemptions are applied to — typically a net positive.
ARC has until March 31, 2027 to resolve 2027/28 grievances. Most cases are resolved by fall 2026. You'll receive a written settlement offer in the mail. If you accept, the reduction shows up on your October 2026 school tax bill.
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