How Property Assessment Reviews Can Lower Tax Bills

When a Long Island property tax bill rises while similar nearby homes sell for less than your assessment suggests, the problem may be the value placed on your property, not the tax rate. A property assessment review lets you challenge that value. If the reviewing body agrees your assessment is too high, it can reduce it, lowering the base your taxes are calculated from. There is one important limit. You can only challenge the assessment on the current tentative roll, not assessments from earlier years, so a missed deadline usually means paying on that value for another full year. 

At Keegan & Keegan, Ross & Rosner, we help property owners in Suffolk County and Nassau County, New York, decide whether an assessment challenge makes sense and build the evidence to support it. A good first step is to compare your current assessment with what your property would realistically sell for today, then confirm the filing deadline for your county, town, or village. 

What an Assessment Review Can and Cannot Change

An assessment review targets your property’s taxable value, not the tax rates set by your school district, town, county, or other taxing authorities. Those authorities decide how much money they need to raise. Your assessment decides how much of that total you pay. A successful review lowers your share, but it can’t stop a school budget increase from raising everyone’s bill. 

Exemptions are separate from the bill. Programs such as STAR reduce taxes through their own application process. In Nassau County, however, the review commission can also correct your tax class and consider an appeal when an exemption was denied, so one filing may address more than a value dispute.  

Grounds for Challenging an Assessment

New York recognizes several grounds for a challenge. The most common is an excessive assessment, meaning the value is higher than your property is actually worth. An unequal assessment means your property is assessed at a higher percentage of its value than other properties in your community. An unlawful assessment covers situations such as property that should be fully exempt. Misclassification applies when a property is placed in the wrong tax class. 

Many Long Island assessing units do not assess at full market value. You may need to convert the number on your assessment roll using your municipality’s assessment level before you can fairly compare it with recent sale prices. A figure that looks low at first glance may actually reflect a market value well above what your home would bring. 

How Nassau County Assessment Appeals Work

Nassau County homeowners file with the Assessment Review Commission (ARC), an independent agency, not a town board. According to the county’s instructions for appealing your assessment, the current filing window runs from January 4, 2027, through March 1, 2027; filing is free, and ARC will never raise an assessment.  

Nassau’s timeline runs well ahead of the bills it affects. Appeals filed in early 2027 challenge the assessment for the 2028–29 tax year. Homeowners who wait for a high bill before acting often find that the window for that assessment has already closed.  

One practical warning: grievance services often ask for signed authorizations before the filing period opens, and if duplicate applications are left unresolved, ARC will deny them. Sign only one authorization, or none if you plan to file yourself.  

How Suffolk County Grievances Work

In Suffolk County, the process begins with your town. You file Form RP-524 with the town assessor or Board of Assessment Review (BAR). Under the state’s grievance procedures for property owners, the Suffolk town BAR meets on the third Tuesday in May. A mailed form must arrive by Grievance Day, and missing that deadline costs you both administrative and court review for the year. 

Owners in villages that assess property face an added step. Those owners have separate town and village assessments, and each requires its own RP-524. Village boards typically meet on the third Tuesday of February, though dates vary. Filing only with the town leaves the village assessment unchallenged.  

Before Grievance Day, you may be able to settle with the assessor. That agreement has consequences. After stipulating to a reduced assessment, you cannot ask the BAR for a further reduction, and if the agreed value appears on the final roll, you cannot seek a lower one in court. 

Evidence That Supports a Lower Assessment

The strongest grievances rely on facts rather than frustration over the size of a tax bill. Useful evidence typically includes recent sales of comparable nearby homes, a professional appraisal, photographs of condition problems, and corrections to errors in the property record, such as overstated square footage, an extra bathroom that doesn’t exist, or a basement listed as finished when it isn’t. In Nassau, the county advises comparing the Department of Assessment’s market value with your own estimate of current value. 

A careful property assessment review starts with a line-by-line check of the assessor’s data. A simple record error is often easier to prove than a disagreement over market value. 

What Happens If Your Grievance Is Denied

A denial at the BAR or ARC level does not necessarily end your options. Owners of a one-, two-, or three-family home used only as a residence may pursue Small Claims Assessment Review (SCAR) for a $30 filing fee. Other owners may bring a tax certiorari proceeding in State Supreme Court under Article 7 of the Real Property Tax Law. Both generally must start within 30 days of the filing of the final assessment roll or notice of that filing, whichever is later. 

In Nassau, SCAR petitions are generally due by the last business day in April, or within 30 days of ARC’s decision if it arrives after April 1, and a SCAR hearing officer can lower an assessment but not raise it. Choosing SCAR involves a tradeoff because filing a small claims petition waives your right to pursue other court review of the same assessment. That decision deserves attention before you file. 

Comprehensive Real Estate Law Services in New York

Thomas J. Keegan Sr. and his son, Thomas J. Keegan Jr., founded our firm in 1978, and real estate law remains part of our practice today. Our work in this area includes property assessment reviews, property tax exemptions, and questions about the STAR exemption. That combination matters because an inflated value, a missing exemption, or both can lead to a high tax bill. 

Our attorneys review your assessment records, check them for errors, gather comparable sales, and file with the correct body before the deadline: ARC in Nassau, or your town and any assessing village in Suffolk. If the first decision falls short, we can explain whether SCAR or a tax certiorari proceeding fits your property. We also offer services in Spanish.  

As a Long Island real estate law firm based in Patchogue, we work with property owners throughout Suffolk County and Nassau County. Bring your latest assessment notice and tax bill to a consultation, and we will help you decide whether to file before the next deadline.