How do I grieve my property assessment in Suffolk County?

Each spring in Suffolk County, property owners have a brief but critical window to challenge their assessments, values that are used to calculate tax bills. 

Property owners have until May 19 to file a grievance, a formal protest of their assessments. In Suffolk, assessments are determined by the 10 towns. In Nassau, the process is different because the county sets the valuations and runs its own grievance process.

"If you feel that the value of the assessment on your home is not [based on] the market value ... then you have the ability to challenge the assessment and file a grievance,” said Lisa Goree, Southampton Town’s assessor, in an interview.

A total of 54,238 property owners filed a residential grievance in 2025 across Suffolk's 10 towns, assessment records show.

A grievance does not challenge the tax bill or the tax rate set by a town, school district, county or other municipality, assessors note. Instead, it contests valuations that are set by the town assessor's office, which can fluctuate based on upgrades to properties, including extensions and home renovations.

Most townwide assessments in Suffolk were completed more than 40 years ago. Southampton Town last assessed in 2019, and Shelter Island reassessed this year, data from the state's Department of Taxation and Finance shows. 

Property owners can file the grievance themselves. But many hire firms that charge a fee if the case is successful — often up to 50% of a projected tax savings. Even a small reduction in assessed value can translate into significant savings, especially in high-tax communities in Suffolk County.

Here’s what to know about how to grieve your assessment, based on guidance from the New York State Department of Taxation and Finance and town assessment departments.

Who can file a grievance?

While most filers are homeowners, the law allows any aggrieved party to file a complaint, including commercial property owners and operators of utility companies. Buyers in contract and some tenants are able to grieve as well.

The grievance must relate to this year’s tentative assessment roll, which is based on valuation data established on July 1, 2025.

Unless you live on Shelter Island, where properties are assessed at 100% of their market value, the assessed value is a percentage of the market value as determined by the town assessor. That uniform percent of value, sometimes referred to as the level of assessment or residential assessment ratio, is based on changes to the real estate market in each town. 

For example, if your home’s market value is $500,000 and the residential assessment ratio is 10%, your assessed value would be $50,000.

Brookhaven Assessor Felix Wienclaw said in a statement that the market value in his town "is a function of the Residential Assessment Ratio. The Town doesn’t change assessed values unless there is a physical change to the property or pursuant to a Court order."

When and where do you file a grievance in Suffolk County?

Taxpayers can file a grievance at their town assessor’s office. 

In Suffolk towns, the Board of Assessment Review meets on the third Tuesday of May, often referred to as “Grievance Day.” This year, it’s May 19. The complaint must be received by the assessment department or the board no later than that day.

Homeowners can submit their paperwork in person or by mail. Some towns, such as Brookhaven, have online applications. 

What do you need to file?

Grievances are filed using Form RP-524, which requires information about the property and the owner’s opinion of its value. 

There are several grounds on which to file a grievance.

Many people challenge on the grounds of an unequal assessment, which occurs when the property’s assessed value is more than it should be compared with others. Assessments are based on the full market value on the assessment roll. 

How can a homeowner make the best case possible?

To make a strong case, homeowners should focus on demonstrating market value, Goree said. For a homeowner, the idea is to argue that your property's market value is lower than what the town assessor estimated.

That means providing examples of "comps," or recent sales of comparable homes in the neighborhood. That data can be accessed through records published in newspapers, or on real estate listing websites like Zillow and Redfin that list recent sales.

A professional appraisal, or documentation of the home’s purchase price, is also helpful. Recent construction or remodeling, the cost of that construction, can also influence whether the assessment can be lowered, Goree said. 

In a large town like Brookhaven, "there are a multitude of local markets" determined by school district, ZIP code, subdivision and other factors, said Adam Heller, the founder of a Long Island grievance firm based in Rocky Point. Heller said grievance firms like his collect that market data and know how best to argue for the reduction. 

How do I determine what I think the assessment should be?

Once you determine what you think your property's market value should be, you can multiply that by the uniform percentage of value, which is listed on the tentative assessment roll.

You can then argue that your home should be taxed at that assessed value, rather than the one on the tentative roll.

To take an example from Huntington's assessment department: Say the town assessed your property at $3,500, or a market value of $897,436. If you have evidence it's worth $800,000, you must convert the figure into an assessed value. Multiply $800,000 by this year's residential assessment ratio of .39%, which results in an assessed value of $3,120. You can argue for that figure in your grievance petition. 

Other grounds for grievances include:

• An excessive assessment, when the assessed value is greater than the property’s full valuation; or an appeal if a tax exemption was denied.
• An unlawful assessment, when a property is incorrectly listed or should be tax exempt. 
• Misclassification, where a property is placed in the wrong assessment class category. 

What happens after you submit the grievance?

After filing a challenge, homeowners have the right to appear before the Board of Assessment Review to present their case, though an appearance is not required.

Once a decision is rendered, the board will issue a written notice with the determination. If the grievance is denied in whole or in part, homeowners can seek further relief through the courts.

Can I appeal?

Owners of one-, two- or three-family homes, and some small residential properties, can file a challenge through the Small Claims Assessment Review process, known as SCAR. The deadline for a SCAR filing varies by town, according to the Suffolk County Clerk's Office.

SCAR hearings are conducted by a judicial hearing officer or court-appointed referee, and the filing fee is $30. Commercial properties and larger residential properties must pursue challenges through the court’s tax certiorari process. 

Newsday's Sam Kmack contributed to this story.