Nassau County is blessed with some of the most desirable real estate in the nation and cursed by some of the highest property values and taxes in the country. Filled with old homes, classic architecture, and history, the county is a unique area adjacent to one of the world’s top cities. The perfect balance of suburban and urban living that drew families to settle in the county is now making things unaffordable. While taxes, taxable value, and demand keep soaring all across Long Island’s counties, longtime business owners and homeowners in Nassau can start feeling the squeeze on all sides. Affordability across the county, but especially in the New York City area, has become a talking point for a reason.
The huge taxable value of Nassau County looks to get an even larger bump, which means taxpayers across the county will be paying billions more in taxes. This will make keeping your home or business that much more difficult. You do have some options to fight these rising costs, including exemptions. However, property tax grievances are a tool that you can use to help even the odds. The deadline to file a grievance with the Assessment Review Commission (ARC) is March 1, 2026. If you want to fight your 2027 property values, you will need to file by that date.
The Nassau Tentative Assessment Roll
The tentative assessment roll for the county was released in January, giving you a preview of how your assessment will change. This can be viewed on the Nassau County Department of Assessment’s website, where they have an advanced property search function that will allow you to find your property. Here you will be able to see the basic details on your property, including its size, the number of rooms, improvements, and classification. You can also see any exemptions that are currently applied to the property. This is a useful tool, as it lets you discover basic errors that can be addressed. For instance, records may indicate that you have a pool or garage that you do not have.
Besides basic errors, you can see your fair market value and your assessed value. The fair market value is what the assessor believes your home would get on the open market. This acts as the basis for your property tax bills and is what you can actually grieve if you think it is incorrect. This makes your fair market value a key number that you need to understand. Your assessed value is likewise derived from this number, which means grieving your market value will have a domino effect on your tax bill.
The Market Value of Homes in Nassau County Jumped 5.7%
To underscore how vital it is to understand your tentative assessment roll, and ensure all numbers are fair, we can look at how much residential property value in Nassau County is set to change. Currently, the noticed value for the county increased by 5.7%. This means a gain of roughly $12.11 billion. While this is a general number across the county and cannot be applied to singular homes, residential value is clearly climbing quickly. As new construction is relatively rare in the county, this could reflect yet another increase in both market and taxable value for homes. This means that you need to review your assessment and make sure that your value is correct.
An Ambiguous Deadline in March
Traditionally, Nassau County sets March 1 as the final deadline for grievances. While most of New York State has a deadline in May, Nassau follows New York City’s counties closely, something fellow Long Island county, Suffolk, does not even do. However, March 1 is a Sunday, which puts things in doubt. As the next business day, March 2, 2026, is the obvious choice, but this has not been decided yet. With the date up in the air, it is important to check with the Nassau County Department of Assessment’s website to make sure you have the right date in mind.
Building Your Grievance Case
While it is natural to want to lower your tax in any way possible, winning a grievance takes a lot of effort if you want to prove that you are overvalued or unequally valued. To demonstrate that your property’s market value is inflated, you must prove it to the ARC by showing sales records of similar homes in your area from the past three years. This includes photographing both your property and those you are comparing them to. You must follow a similar process to prove that your property is being valued more than your neighbors, though you do not have to go to realtors to find out sale prices. Either approach takes a lot of work to prove, though with huge tax burdens on the line, it is usually worth it. If you want an overview of filing a grievance in Nassau County, we have an in-depth article about it.
O’Connor is Here to Help You Grieve Your Taxes
Thanks to how complicated it is to prove errors in overvaluation and uniformity, many taxpayers give up. We at O’Connor are here to lend a hand so that you only pay what you truly owe. For over 50 years, we have been fighting for our clients across the nation. Property tax fairness is our No. 1 goal, and we were able to help 185,000 clients in 2024 alone. We will guide you each step of the way, from analyzing your assessment, filing a grievance, and representing you in front of the ARC. If that fails, we will even represent you in legal cases to get you the reduction that you deserve.
While we are a national company, our branch office on Long Island, in Nassau County is dedicated to serving New York property owners. Backed by our national resources, our New York team can provide you with all of the help you need. They will gather the evidence needed to win your grievance, use our patented databases to study sales records and comparisons, and be your representative at every hearing. To top it all off, you will never be charged upfront for this assistance. You are only billed a contingency fee if we can lower your taxes, meaning you only pay if you win.
