Learn the Key Differences Between the Nassau County & Suffolk County Tax Grievance Processes

If you own commercial property on Long Island, it’s important to understand that the Tax Grievance process is not the same in Nassau County & Suffolk County. Some property owners own buildings in both counties, and it can save a lot of time and aggravation to understand the key differences in how each county handles tax grievances.

Here is what you need to know:

Tax Assessment Rolls & Grievance Deadlines:

In Nassau County, Department of Assessment will determine a tentative assessment for every property as of January 4. If you believe the assessment is inaccurate, you may appeal by filing an application for correction with the Assessment Review Commission by March 1.

In Suffolk County, most towns will publish the tentative assessment roll on May 1 and you will have until the 4th Tuesday in May (in most communities) to file your grievance.

You may be concerned that the property tax assessor has over-assessed the value of your property. Considering that Long Island has some of the highest real estate taxes in the country, you could be losing a lot of money if you are over-assessed.

The newly created Disputed Assessment Fund (“DAF”) has also resulted in a substantial increase in tax rates throughout Nassau County.

Some factors that you may not realize can affect assessments:

  • Have the rents in your building or surrounding areas gone down, while vacancy rents increased? Is the Market Value that appears on your tax bill higher than the amount you could realistically sell your property for?
  • Does your roof need replacing or your parking lot need repaving? Is your parking lot well-lit? Are your HVAC units old and inefficient?
  • Property tax assessments can be artificially inflated because of perceived business value. Assessments are supposed to be the same, regardless of the brand that goes on the sign! For example, two identical motel buildings across the street from each other should have approximately the same property value. But the one with the national branding is assessed much higher.

Taxing Municipality:

On LI, the taxing municipality is different depending upon whether your property is located in Suffolk County or Nassau County:

  • Nassau County property owners pay their taxes to the County.
  • Suffolk County property owners pay their taxes to their specific town; Town of Huntington, Islip, Babylon, Brookhaven, Southampton, East Hampton, Southold, Smithtown, Riverhead, and Shelter Island.
  • In both Nassau & Suffolk counties, if your property is located within a village you may be assessed additionally from the village.


The process of filing is very different in Nassau County than in Suffolk County:

  • Nassau County has an Assessment Review Commission in place that handles the initial grievance. In Nassau County, once you have received your assessment, if you would like to grieve your taxes, you can appeal online from January 3 to March 1, at this link Nassau County Online Appeal
  •  In Suffolk County, the initial appeal is handled by the Board of Assessment Review (BOAR). Additionally, each Town in Suffolk handles the appeal process differently and has different requirements depending upon the assessor’s requirements and the town attorney’s requirements.


  • In Nassau County if you file a tax grievance and are successful, you may refile again the next year.
  • In Suffolk County, once you obtain a reduction for properties owned within the county, the county agrees to hold the assessment at the reduced rate for the next three years so you would not file for the next three years unless the assessment is increased.


  • Nassau County has instituted a new law which applies to all Class 4 Commercial property owners. This law requires that a percentage of those taxpayers’ payment be held in separate accounts until the tax appeal is resolved. If a refund is owed to the tax payer, Nassau County will pay from the monies held in the DAF Account. If the refund is less than the amount held, the additional funds shall be sent to the taxing jurisdiction.

It is important to note that assessors do not determine your property taxes, they can only assist with helping to assess the value of your property. If you find that your property’s actual value is lower than the assessed value that the town or municipality has assigned to your property, you file your grievance and try to get a reduction based on that filing. Filing a grievance and challenging your property tax assessment is a process called tax certiorari. 

However, if the grievance filing is denied, there are further steps that can be taken.

Given these differences, and the potential complexities of the grievance filing and any follow-up actions, it is recommended to work with a property tax expert.

Realty Tax Challenge (“RTC”) can help you grieve your Nassau or Suffolk County property tax assessment to achieve real estate tax reductions and potentially a tax refund. We can provide a no-cost consultation to determine whether your Long Island commercial property is over assessed and whether you should appeal your assessment.

Our highly experienced staff has been helping Long Island and NY State commercial property owners reduce their real estate taxes every day for the last 22 years. We are the best and most knowledgeable in the business at understanding real property values and have achieved over $50 million in real estate reductions for our clients.

Working with an experienced consultant like Realty Tax Challenge is the best way to increase the likelihood of success. Call us today to speak with a tax assessment specialist at 914-348-9473 or contact us!

Related Posts:

What You Need to Know About Nassau County Commercial Property Tax Grievance – Due Dates & More

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