Property Taxes in Port Washington: Nassau County's Unusual System, Explained
Nassau County's property tax system is genuinely different from most of the country, and it has been the subject of real, well-documented controversy and litigation for decades -- most recently an appellate court decision in October 2025 that kept a homeowners' constitutional challenge alive. This page walks through how the system actually works, what changed in 2020, and what a buyer should know before assuming a tax notice tells the whole story.
Four Layers, One Parcel
A Port Washington property owner can owe property tax to as many as four separate taxing jurisdictions on a single parcel: Nassau County, the Town of North Hempstead, the relevant incorporated village if the parcel sits inside one of the four village governments on the peninsula (Baxter Estates, Manorhaven, Port Washington North, or Sands Point), and the Port Washington Union Free School District, which typically represents the largest single component of the total bill. A parcel in the unincorporated hamlet core skips the village layer; a parcel inside Sands Point or one of the other incorporated villages does not.
This layered structure isn't unique to Nassau County -- many New York communities stack county, town or city, and school taxes -- but Nassau adds a genuinely unusual wrinkle on top of it: how the assessed value each of those jurisdictions taxes against is actually calculated.
The Old System: Assessments Frozen in 1938 and 1964
For years, Nassau County valued residential property using a method tied to 1938 construction costs less depreciation, plus land value as of 1964 -- meaning a home's official assessed value was rooted in economic conditions from the Great Depression and the Kennedy/Johnson era, updated only piecemeal, long after those numbers had any real relationship to what the home would actually sell for. That disconnect drove a real, sustained wave of tax certiorari litigation, primarily from commercial and industrial property owners challenging their assessments as inaccurate, and contributed to roughly $100 million to $150 million in certiorari judgments against the County over time. The County eventually created a Disputed Assessment Fund under its own administrative code specifically to manage the fiscal impact of Class 4 commercial certiorari settlements -- a structural fix built around managing litigation costs rather than fixing the underlying valuation problem.
Compounding the issue, Nassau's assessment roll was frozen entirely in 2011 by the prior county administration, meaning assessed values didn't update at all for years even as actual home values moved with the market -- a real gap between paper value and market reality that widened every year the freeze remained in place.
The 2018-2020 Reassessment and the Taxpayer Protection Plan
County Executive Laura Curran ordered a full countywide reassessment beginning in 2018, explicitly framed as restoring accuracy, fairness, and integrity to a system that had drifted for years under the freeze and the outdated 1938/1964 valuation method. Because a single-year jump to accurate market-based assessments after nearly a decade of no updates threatened to produce large, sudden tax-bill swings for individual homeowners, the Nassau County Legislature passed the Reassessment Phase-In Act (RPIA) on March 23, 2020 -- also referred to as the Taxpayer Protection Plan. Under the RPIA, any increase to a property's assessed market value resulting from the reassessment is phased in gradually, at 20% of the increase per year for five years, beginning with the 2020-21 tax year, rather than applied all at once.
This page did not find a confirmed, sourced figure for the overall magnitude of the countywide reassessment (for example, an average percentage value increase across all Nassau parcels) and does not state one. What is confirmed is the mechanism -- a five-year, 20%-per-year phase-in -- and that it was designed specifically to smooth out exactly the kind of one-time shock a decade-long assessment freeze would otherwise produce.
The 10% Level of Assessment: Why the Notice Doesn't Match the Price
Since the 2020-21 cycle, Nassau has fixed the Level of Assessment (LoA) for Class 1 property -- one-to-three-family residential homes, which covers the vast majority of Port Washington housing stock -- at 10% of the property's determined market value. In practical terms, this means the County first estimates what a home would sell for, then states its official 'assessed value' as exactly 10% of that number, and applies tax rates against that reduced figure. A home the County estimates at $1,500,000 in market value would therefore show an assessed value of $150,000 on its tax notice -- not because the County thinks the home is worth $150,000, but because 10% is the deliberate, fixed ratio the system uses.
This is a genuinely important thing for a buyer moving from almost any other county to understand before reading a Port Washington tax record: the 'assessed value' line is not a market-value estimate and should never be compared directly to a listing price or an appraisal. It is a calculation input, fixed at a known 10% ratio, that only makes sense in the context of the tax rates applied against it. This is also structurally different from Westchester County's system, which uses its own separate assessment methodology and ratios -- a buyer comparing a Port Washington tax bill to a Westchester-area property (Port Chester or Pelham, for instance) should not assume the two counties' assessed-value figures are calculated the same way.
An Active, Unresolved Legal Challenge
Nassau's assessment system remains a live legal controversy, not settled history. As recently as October 2025, the New York Supreme Court's Appellate Division, Second Judicial Department revived a challenge brought by a group of Nassau County homeowners, finding they had sufficiently alleged financial injury to have standing to sue over the current property assessment system on equal-protection and due-process grounds. This page does not know, and does not guess, how that litigation will ultimately resolve or whether it will change the system a Port Washington buyer encounters going forward -- it flags the case as real, current, and worth watching, not as background history.
Separately, Nassau County Republicans in the County Legislature have proposed a 'Taxpayer Bill of Rights' aimed at adding further protections to the reassessment process, reflecting genuine, ongoing political disagreement over how the system should work -- another sign this is an actively contested area of local policy rather than a fixed, uncontroversial framework.
STAR: The Main Relief Program a Buyer Should Know About
New York's School Tax Relief (STAR) program is the primary property tax relief mechanism available to a Port Washington homeowner, administered by the NY Department of Taxation and Finance rather than Nassau County itself. The Basic STAR benefit subtracts $30,000 from a home's assessed value specifically for calculating the school-tax portion of the bill, for owner-occupiers of a primary residence generally under a stated household income threshold (cited up to $500,000 for STAR credit eligibility in current sourcing, though eligibility rules can change and should be confirmed directly). Enhanced STAR provides a larger benefit to qualifying senior homeowners who meet separate, lower income requirements. For newer applicants, STAR is typically delivered as a STAR credit check mailed directly by NY State rather than as an upfront exemption on the tax bill itself -- a real, practical difference in how the benefit shows up depending on when an owner enrolled.
This page does not state a specific current dollar-value benefit STAR would produce for a hypothetical Port Washington property, since that depends on the specific school tax rate applied and whether Basic or Enhanced STAR applies -- confirm eligibility and the current benefit amount directly with the NY Department of Taxation and Finance or the Port Washington Union Free School District.
What a Buyer Should Actually Do
Before making an offer on a Port Washington property, pull the parcel's current assessed value, its Level of Assessment status, and its most recent combined tax bill directly from the Nassau County Department of Assessment -- not from a real estate listing site, which may show a stale or misleading figure given how the 10% ratio works. Confirm whether the specific address sits inside one of the four incorporated villages (which adds a village tax layer) or in the unincorporated hamlet, ask directly whether any RPIA phase-in adjustments are still working through that specific parcel's bill, and ask whether the property currently receives a STAR benefit that would need to be re-applied for after a sale.
This page does not state a property tax proration formula for a mid-year closing in Nassau County, nor a definitive prediction of how the October 2025 appellate case will affect future assessments -- those are exactly the kind of specific, current, case-by-case facts a Nassau County-licensed real estate attorney and the Department of Assessment should confirm directly rather than assuming a generic answer applies to your closing.
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Get a Free Agent Referral →Independent research. No ads. No sponsored listings. Data sourced from: City Journal's reporting on New York's property-assessment regime; Law.com's October 2025 reporting on the Appellate Division, Second Judicial Department reviving Nassau homeowners' constitutional challenge to the assessment system; Ownwell's, Maidenbaum Property Tax Reduction Group's, and Heller & Consultants Tax Grievance's guides to Nassau County's reassessment, the 2018-2020 Curran reassessment, the March 2020 Reassessment Phase-In Act (Taxpayer Protection Plan) and its 20%-per-year, five-year phase-in mechanism, and the 10% Level of Assessment for Class 1 residential property since the 2020-21 cycle; the Nassau County Comptroller's own field audit report and Justia's case law summary of Matter of O'Shea v. Board of Assessors of Nassau County for the historic 1938-construction-cost/1964-land-value assessment method, tax certiorari judgment costs, and the Disputed Assessment Fund; CBS News New York's reporting on the Nassau County reassessment process, resident pushback, and the Republican-proposed Taxpayer Bill of Rights; and general STAR program guidance for the Basic STAR $30,000 assessed-value reduction, Enhanced STAR for seniors, and the shift toward STAR credit checks for newer applicants. Facts not independently confirmed and not invented here include: the overall percentage magnitude of the 2018-2020 countywide reassessment; a specific current school, town, county, or village tax rate for a given Port Washington parcel; the current income threshold and benefit amount for Enhanced STAR specifically; and any prediction of how the pending October 2025 appellate litigation will resolve. Confirm all current figures and eligibility directly with the Nassau County Department of Assessment, the NY Department of Taxation and Finance, the Town of North Hempstead, and a Nassau County-licensed real estate attorney before making a purchase decision. Nothing on this page is tax or legal advice.