By Eric Berman, REALTOR® | The Eric Berman Team at Compass
TL;DR:
Nassau County froze residential property assessments in 2021, and the freeze has continued through the 2025-26 tax year. For Long Island sellers, this creates a quietly significant disconnect: a home's assessed value may have little to do with its current market value. Homes that have appreciated significantly since 2020 are typically under-assessed (paying less in tax than their fair share); homes that lost value or were over-assessed before the freeze are paying more than they should. Either situation affects how a sale is positioned, how buyers think about future tax exposure, and when sellers should plan ahead for the eventual end of the freeze.
What the Nassau County Reassessment Is — And Why It Matters
A property tax reassessment is the process by which a county updates the assessed values of homes to reflect current market conditions. In most counties, this happens regularly — annually, every few years, or on a published cycle — so that the assessed value used to calculate property taxes stays reasonably aligned with what the home would actually sell for.
Nassau County's reassessment story is one of the most politically fraught in New York. The county hadn't done a full reassessment for decades when, in 2018, then-County Executive Laura Curran ordered a county-wide reassessment that took effect for the 2020-21 tax year. The reassessment used a sophisticated computer-assisted mass appraisal system that recalculated values for hundreds of thousands of homes simultaneously. The results were dramatic. Some neighborhoods saw assessments rise sharply; others saw drops. Tax burdens shifted across town and village lines in ways that produced years of grievance filings, lawsuits, and political backlash.
In 2021, under pressure from homeowners, Nassau County froze the reassessment process. Assessed values that took effect for the 2020-21 tax year have remained essentially unchanged since. The freeze was originally a short-term political measure; it has now lasted four years and is expected to continue through the 2025-26 tax year, with no clear date for when it will end.
For Long Island sellers, this freeze creates a specific and important reality: the assessed value on a home's tax bill today reflects what the county thought the home was worth in 2020. For a home that has appreciated by 30%, 40%, or 50% since then — which describes a substantial portion of the North Shore and broader Nassau market — the assessed value is now meaningfully out of date.
How the Freeze Affects Sellers Right Now
The freeze affects Long Island sellers in three distinct ways, and they're worth separating.
The first is how the assessed value compares to current market value. For sellers whose homes have appreciated significantly since 2020, the assessed value is likely lower than the market value. This is actually favorable for the seller during the holding period — the home is effectively under-taxed relative to what a fresh reassessment would produce. But it's worth understanding: this gap exists.
For sellers whose homes have lost value, or whose homes were over-assessed during the 2020 reassessment process and never successfully grieved, the assessed value may be higher than current market value. These sellers are over-paying property taxes, and a successful tax grievance would reduce that bill.
The second is what happens to property taxes when the buyer takes ownership. In Nassau County, the assessed value stays with the property, not the owner. A buyer purchasing the home inherits the existing assessment and the existing tax bill. This is different from California's Proposition 13 system, where assessments reset to the sale price at transfer. In Nassau, a sale doesn't trigger a reassessment.
That's important for buyer perception. A buyer looking at a Manhasset home with a $20,000 annual tax bill is buying that tax bill, not a future reassessment risk based on what they paid. As long as the freeze continues, the tax bill they take over is the tax bill they'll pay (subject to the annual adjustments the county makes within the existing assessment framework).
The third is what happens when the freeze eventually ends. This is the planning question that matters most for sellers thinking about the longer arc. The freeze is not permanent. When the county eventually unfreezes — whether that's 2026, 2027, or later — there will be another reshuffling of assessments to bring them closer to current market values. Homes that have appreciated significantly will likely see their assessments rise, and their tax bills with them. Homes that have lost value relative to neighbors may see assessments drop.
The size of this future adjustment matters for sellers planning to list in the next few years. A buyer purchasing today inherits a 2020-vintage assessment; if they plan to hold the home for ten years, they will almost certainly experience an assessment update at some point during their ownership, with consequences they can't fully predict today.
What This Means for Tax Grievances
The grievance process — challenging the county's assessment to lower property taxes — is still active even during the freeze. Homeowners can file annually with the Assessment Review Commission (ARC). The window for the 2027/28 tax year closed March 31, 2026, and the next window for the 2028/29 tax year opens January 2, 2027.
For sellers, grievance timing matters in a specific way: a successful grievance lowers the buyer's eventual tax bill, which can be a real selling point. But the grievance is filed by the current owner, applies to a future tax year, and may or may not be resolved before the sale closes. Sellers who have a strong grievance case but haven't filed should think about whether to file before listing — partly because the lower tax bill (even if it materializes after closing) accrues to the buyer, which can affect what they're willing to pay; and partly because the documentation behind a strong grievance case is useful information to share with prospective buyers.
For sellers in homes that are clearly over-assessed and haven't grieved, the math is simple. Filing costs nothing if done individually, or a contingency fee (typically 50% of first-year savings) if done through a grievance service. The downside is essentially zero — if denied, taxes stay the same.
How the Reassessment Conversation Affects Pricing and Negotiation
For most Long Island sellers, the assessment-versus-market-value gap doesn't directly affect the listing price. Buyers price homes based on comparable sales, not based on assessed values. A home priced at $1.5M sells at $1.5M whether the assessment is $1.1M or $1.4M.
What the assessment does affect is buyer comfort with the ongoing tax bill. A savvy Long Island buyer looking at two comparable Manhasset homes — one with a $18,000 annual tax bill, one with $24,000 — will weight that difference into their offers. The $24,000-tax-bill home effectively costs them more to own each year, which can be reflected in a slightly lower offer, all else equal.
Sellers in homes with relatively high tax bills compared to neighbors should expect this to come up. The best response is preparation: knowing the assessment history, knowing whether a grievance has been filed (and the outcome), and knowing what the comparable tax bills are in the immediate neighborhood. A listing agent who handles this proactively in conversations with buyers' agents removes a potential objection before it becomes a price negotiation.
For broader context on the full set of seller-side tax and cost considerations that shape a Long Island home sale, the closing costs breakdown for Long Island sellers walks through every cost the seller faces at closing.
The Interaction With Federal Tax Changes
Nassau County's reassessment freeze isn't happening in a vacuum. It overlaps with the federal SALT cap changes that took effect in 2025, which dramatically affect how much of those Nassau property taxes Long Island homeowners can deduct on their federal returns. The new $40,000+ SALT cap (subject to income phase-down) means more of the property tax bill is now deductible federally, which softens the after-tax cost of owning a home with high Nassau taxes.
For a fuller view of how those federal SALT changes interact with Long Island home sales, the SALT cap impact analysis for Long Island sellers covers what the higher cap means at different price points and income levels.
The combination matters: lower assessments under the freeze plus higher SALT deductibility under the new federal cap means many Long Island homeowners are currently better-positioned, after-tax, than they have been since 2017. For sellers, this means the buyer pool's affordability is genuinely improved compared to where it was two or three years ago.
Planning for the Eventual End of the Freeze
The freeze cannot continue forever. New York State law requires counties to maintain reasonably current assessments, and Nassau has been operating in tension with that requirement for years. When the freeze ends — whether through political change, legal pressure, or simply administrative reality — there will be another wave of assessment adjustments, likely producing significant changes for individual homes.
For sellers thinking about the timing of a sale, this matters less than it might seem. The freeze's end is not a near-term certainty, and trying to time a sale around it is rarely a wise strategy. Life-stage considerations, financial planning, and the right moment for the seller's situation are almost always more important inputs than guessing at a tax policy change.
But for sellers in homes that have appreciated significantly since 2020 — particularly luxury and waterfront properties in Manhasset, Port Washington, Garden City, Roslyn, Plandome, Old Westbury, Locust Valley, and Sands Point — the eventual reassessment is worth at least one conversation. A home that's currently assessed at $1.2M but would likely assess at $2M post-freeze will produce a meaningfully higher tax bill for the buyer eventually. Disclosing this risk early in the marketing process, or simply being prepared to discuss it candidly when buyers ask, is the kind of honesty that builds trust during a negotiation.
For sellers wanting an early sense of what their home's market value looks like today — separate from the (likely outdated) assessed value on the tax bill — the home valuation tool is a useful starting point.
The Long Island Bottom Line
The Nassau County property tax reassessment situation is unique among large American counties in 2026. A four-year freeze on residential assessments has produced a market where many homes' tax bills reflect 2020 valuations rather than current market reality. For sellers, this is mostly a backdrop — it doesn't typically change the listing price or the closing math directly. But it affects buyer affordability calculations, it shapes whether a tax grievance is worth filing before listing, and it creates a longer-term risk that buyers may eventually face a meaningful tax increase whenever the freeze ends.
The right approach for most Long Island sellers is to understand where the assessed value sits relative to current market value, to know whether a grievance has been filed and at what outcome, and to be ready to discuss the assessment situation candidly with buyers' agents during negotiation. The county's reassessment story is not over. But for the next few years, sellers who understand the landscape will navigate it more confidently than sellers who don't.
Q: Has Nassau County reassessed property values recently?
A: No. Nassau County conducted a full county-wide reassessment that took effect for the 2020-21 tax year, then froze further reassessments starting in 2021. The freeze has continued through the 2025-26 tax year, meaning assessed values have remained essentially unchanged for four years. There is no published date for when the freeze will end.
Q: Does selling a Long Island home trigger a property tax reassessment?
A: No. In Nassau County, the assessed value is attached to the property, not the owner. When a home sells, the buyer inherits the existing assessment and the existing tax bill. There is no automatic reassessment at sale, unlike some other states. As long as the county-wide freeze continues, sale prices do not trigger individual property reassessments.
Q: When does the Nassau County tax grievance window open and close?
A: The grievance window typically runs from January 2 to March 1 (or March 31 in extended years) of each year, applying to the tax year that begins approximately 16 months later. The window for the 2027/28 tax year closed March 31, 2026. The next window, for the 2028/29 tax year, opens January 2, 2027. Filing is free if done individually, or done on a contingency-fee basis through a grievance service.
Q: What happens to property taxes when the Nassau County reassessment freeze ends?
A: When the freeze eventually ends, assessed values will be updated to better reflect current market conditions. For homes that have appreciated significantly since 2020 — which describes much of the North Shore and broader Nassau market — assessed values are likely to rise, and tax bills with them. For homes that lost value or were over-assessed in 2020, assessments may drop. The size and timing of this future adjustment is uncertain, but it's worth understanding as a longer-term consideration for both current owners and prospective buyers.
Q: Should a Long Island seller file a tax grievance before listing?
A: It depends on the home's specific situation. For homes that are clearly over-assessed relative to current market value, filing a grievance is usually worthwhile — it costs nothing to file individually, the downside is zero, and a successful grievance lowers the eventual tax bill (which can be a selling point or even reflected in the sale price). For homes that are under-assessed or fairly assessed, there's no reason to file. The decision is best made with a tax grievance professional or a knowledgeable listing agent who has reviewed the comps and assessment history.
For Long Island sellers thinking through a sale in a market where property tax assessments are frozen in time, the most useful thing is information. Understanding where a home's assessment sits relative to current market value, knowing the grievance options, and being prepared to discuss the assessment landscape during negotiation are what separate a confident sale from a defensive one. When the time is right to talk through what a specific home's tax-and-market picture looks like, the door is open.
By Eric Berman, REALTOR® | The Eric Berman Team at Compass
Eric Berman | Long Island & Queens REALTOR® | Compass 1468 Northern Blvd, Manhasset, NY 11030 (917) 225-8596 | eric@ericbermanteam.com | theericbermanteam.com
