By Eric Berman, REALTOR® | The Eric Berman Team at Compass
TL;DR:
Nassau County runs its assessment cycle roughly eighteen months ahead, which means a grievance filed in early 2027 challenges the 2028–2029 tax year and produces savings that first appear on an October school tax bill more than a year later. A seller listing in spring will almost certainly never see that money — the buyer will. That does not make grieving pointless, but it changes why a seller would do it, and it introduces a trap most homeowners never hear about: grievance firms work on contingency, and the fee follows the case rather than the house. A seller who files and then sells without formally assigning the case can end up paying the fee while the buyer banks the savings. The fix is a contract term, and it belongs in front of a real estate attorney before the grievance is ever filed.
The Eighteen-Month Lag Nobody Explains
Every January, Nassau County publishes a tentative assessment roll, and the filing window opens. What almost nobody explains is how far ahead that roll is looking.
A grievance filed in the window that opens in early 2027 does not challenge the tax bill arriving that year. It challenges the 2028–2029 tax year. The Assessment Review Commission then has until March 31 of the following year to resolve the case. If a reduction is granted, it first shows up on an October school tax bill and then on the January general tax bill after that.
Add it up and the gap between filing and seeing a dollar can run well past a year and a half. For a homeowner planning to stay, that lag is simply how the system works and the savings compound annually once they arrive. For a seller listing in spring, the arithmetic is different and worth being honest about: the reduction will land after the closing, on a bill addressed to someone else.
This is the part the grievance industry does not lead with, and it is the first thing a seller should understand before deciding whether to file.
So Why Would a Seller Bother?
There are real reasons, and they are worth separating from the ones that get oversold.
The strongest is that timelines slip. Deals fall through, sellers change their minds, a job transfer gets postponed, an estate takes longer to settle than anyone expected. A homeowner who assumed a spring closing and is still holding the property eighteen months later will be glad the filing happened. Filing costs nothing directly and preserves an option, and the window closes whether or not the house sells.
The second is carrying cost. An assessment that is out of step with comparable homes shows up as a tax bill out of step with comparable homes, and buyers evaluating a purchase run the taxes alongside the price. A high bill relative to the neighborhood is a real objection, and it tends to surface as a price conversation rather than a tax conversation.
What sellers should treat skeptically is the claim that a pending grievance is itself a selling point. That framing comes almost entirely from firms whose business depends on filings. A pending case is not a reduction — it is an unresolved application with no guaranteed outcome, and a well-informed buyer will treat it that way.
The Contingency Fee Trap
This is the part that costs sellers actual money, and it is almost never discussed outside the fine print.
Most Nassau homeowners file through a grievance firm working on contingency, taking a percentage of the first year's savings. The fee attaches to the case, not to the property. So when a seller files, sells, and the reduction lands months later on the new owner's bill, the savings belong to the buyer while the fee obligation stays with the person who signed the agreement.
The industry's own guidance on this is unambiguous: a seller must obtain the purchaser's signed acceptance of an assignment of the tax assessment reduction agreement. Without that assignment, the seller remains responsible for the fee. With it, the party receiving the benefit is the party paying for it.
That assignment is a contract term, which means it belongs in front of a real estate attorney early — ideally when the grievance is filed, and certainly before a contract is signed. It is a small clause and an easy one to include. It is also easy to forget entirely, and the reminder tends to arrive as an invoice months after the closing for savings the seller never received.
Sellers who file directly with the Assessment Review Commission through its online portal avoid the fee question altogether, since filing with ARC carries no charge. That path takes more effort and requires assembling comparable sales evidence without help, but for a homeowner who is organized and already thinking about comparable sales because they are preparing to sell, it is a reasonable option.
The Village Filing Almost Everyone Misses
Here is the error that costs Port Washington homeowners more than any other, and it exists because of how this peninsula is governed.
Nassau County and the incorporated villages use different assessors. Villages are not required to follow the county's assessment roll and are entitled to create their own. Their filing deadlines are separate from the county's and differ from village to village.
The practical consequence is that a homeowner in Baxter Estates, Flower Hill, Manorhaven, Port Washington North, or Sands Point who files a grievance with the county has addressed exactly one of the two assessments applying to their property. The village assessment sits untouched, on its own roll, with its own deadline that has likely already passed by the time anyone notices.
Homeowners in the unincorporated portion of Port Washington, under the Town of North Hempstead, have only the county filing to make. Which one applies depends entirely on jurisdiction — and on this peninsula a mailing address does not answer that question. The six governments sharing the Port Washington address each operate independently, and whether a separate village tax bill arrives is the fastest way to tell which situation applies.
Sellers who have grieved once and assumed they were finished are frequently halfway done.
What Filing Actually Involves
The mechanics are less intimidating than the industry's marketing suggests.
The county window opens in early January when the tentative roll publishes. The statutory deadline is March 1, though Nassau has granted extensions in recent years — the most recent cycle ran to March 31. Sellers should plan around March 1 and treat any extension as a bonus rather than an assumption.
Filing is done through the Assessment Review Commission's online portal, at no cost. The case is built on comparable sales showing similar homes valued below the assessment. That evidence overlaps almost entirely with the comparable sales work a seller is doing anyway, which is one argument for handling both at the same time.
There is no downside risk to the assessment itself. ARC can reduce an assessment or leave it unchanged. It cannot increase it as a result of a filing.
If ARC offers a reduction, the homeowner accepts or rejects it. If the offer is rejected or none is made, the next step is a Small Claims Assessment Review petition filed at the county clerk's office for thirty dollars, refundable on a win, with a hearing officer required to decide within forty-five days. SCAR requires the property to be owner-occupied, so it is not available on an investment property or a vacant inherited home. The same January window is also the deadline for exemption filings including STAR, veterans, and senior exemptions, which is worth knowing for anyone who has moved or whose circumstances changed.
A Composite Example: The Invoice After the Closing
Consider a composite drawn from patterns that recur here. A Port Washington homeowner decides in January to list in the spring. On a neighbor's recommendation, they sign with a grievance firm working on contingency and think no more about it.
The house goes under contract in April and closes in June. The following spring, ARC grants a reduction. It appears on the October school tax bill, which goes to the buyer, and the buyer's carrying cost drops accordingly.
The seller, now living elsewhere, receives an invoice for the contingency fee on savings they never received. Because the case was never assigned to the purchaser at closing, the obligation stayed with them.
The fix would have taken one sentence in the contract of sale. Their attorney would have included it without hesitation, had anyone raised it. Nobody did, because the grievance was signed in January and the attorney was engaged in March, and the two conversations never touched.
Where to Start
Confirm jurisdiction first. Whether a separate village tax bill arrives determines whether one filing or two are required, and the village deadline is the one people miss.
Decide whether to file directly with ARC or through a firm. Direct filing is free and the evidence overlaps with pre-listing comparable sales work. A firm is easier but introduces the fee question.
If using a firm, raise the assignment before signing anything, and tell the real estate attorney a grievance is pending as soon as one is engaged. The assignment clause is straightforward when handled early and awkward when raised at the closing table.
Mark the calendar for early January and plan around a March 1 deadline. If a listing is anticipated in the same year, treat the filing as insurance against a timeline that slips rather than as a savings strategy.
And keep the two conversations connected. Most of the damage here comes from a grievance filed in January and an attorney engaged in March who never learn about each other.
The Honest Bottom Line
Grieving before a sale is worth doing, but not for the reason most sellers assume. The savings will very likely go to the buyer. What a seller gets is protection against a timeline that moves, and a tax bill that does not undercut the asking price.
The thing actually worth attention is the fee. A grievance signed casually in January, on a neighbor's recommendation, can produce a bill months after the closing for money that went to someone else. That outcome is entirely avoidable, and avoiding it costs one clause and one conversation.
This post covers process, not legal or tax advice. Eric Berman is not an attorney or a tax professional. Assessment challenges, contingency agreements, and assignment clauses should be reviewed by a New York real estate attorney, and tax questions directed to a CPA. Filing deadlines and village procedures change; confirm current dates with the Nassau County Assessment Review Commission and the relevant village before relying on any date here.
For sellers thinking through how carrying cost affects a listing, a closer look at what determines Port Washington home values covers the broader picture, and a current look at home values is a practical starting point.
FAQs
If a grievance succeeds after the house sells, who gets the savings?
The buyer. Nassau's assessment cycle runs roughly eighteen months ahead, so a grievance filed in early 2027 challenges the 2028–2029 tax year, and any reduction first appears on an October school tax bill and the following January general tax bill. A seller who closes before those bills issue will not see the reduction. This is the most common misunderstanding about grieving before a sale, and it is worth resolving before signing anything — particularly with a contingency firm, where the fee obligation can outlast the ownership.
What happens to a pending grievance when the home sells?
It does not transfer automatically. Industry guidance is that the seller must obtain the purchaser's signed acceptance of an assignment of the tax assessment reduction agreement. Without that assignment, the seller remains responsible for any contingency fee even though the buyer receives the savings. The assignment is a contract term, so it belongs with the real estate attorney — ideally raised when the grievance is filed and certainly before a contract is signed. Sellers who file directly with the Assessment Review Commission avoid the issue, since filing with ARC carries no fee.
Can filing a grievance make the assessment go up?
No. The Assessment Review Commission can reduce an assessment or leave it unchanged, but it cannot increase it as a result of a filing. That is what makes the decision to file relatively low-risk on the assessment side. The risks that do exist are elsewhere: missing a village deadline, or signing a contingency agreement without understanding how the fee behaves if the property sells before the case resolves. Sellers should weigh those rather than worrying about the assessment itself.
Does a Port Washington homeowner have to file twice?
It depends on jurisdiction. Nassau County and the incorporated villages use different assessors, villages are not required to follow the county's roll, and village filing deadlines differ from the county's. A homeowner in Baxter Estates, Flower Hill, Manorhaven, Port Washington North, or Sands Point who files only with the county has left the village assessment unaddressed. Homeowners in the unincorporated area under the Town of North Hempstead have only the county filing. Whether a separate village tax bill arrives is the fastest way to tell which applies.
When does the next filing window open?
The county window opens in early January when the tentative assessment roll publishes. The statutory deadline is March 1, though Nassau has granted extensions in recent cycles — the most recent ran to March 31. Because extensions are discretionary rather than guaranteed, sellers should plan around March 1. Village deadlines are separate and vary, so anyone in an incorporated village should confirm theirs independently. The same January window is also the deadline for exemption filings including STAR, veterans, and senior exemptions.
By Eric Berman, REALTOR® | The Eric Berman Team at Compass
Eric Berman | Long Island & Queens Associate Broker | Compass
1468 Northern Blvd, Manhasset, NY 11030
(917) 225-8596 | eric@ericbermanre.com | theericbermanteam.com
