How to renew your tax grievance on Long Island

Nassau’s Assessment Review Commission (ARC) is explicit: a representative’s authorization is valid for only one filing. If a grievance company filed for you last year, it needs a new signed authorization from you before it can file for the 2028/29 tax year.

ARC publishes the rules for each year’s authorization. For the 2028/29 tax year, it must include:

• The tax year, written out (for example 2028/29). A calendar year alone isn’t enough.
• The representative’s name and ARC-assigned number.
• The property address and its Section, Block and Lot.
• The name of the person signing and their relationship to the property (and title, for a business).
• An original signature and a date written in by the signer, not pre-printed.

The signature can be dated no more than 120 days before the first filing date of January 4, 2027, so not before September 6, 2026. The company uploads it to AROW during the filing period, January 4, 2027 to March 1, 2027.

There’s nothing to renew. File a new application each year: in Nassau through AROW between January 4, 2027 and March 1, 2027; in Suffolk with your town by Grievance Day. Last year’s evidence is a good start, but update it with this year’s sales.

Suffolk towns take a new grievance complaint (Form RP-524) each year, by Grievance Day, the third Tuesday in May (Tuesday, May 18, 2027). If a company files for you, ask whether your agreement covers this year and whether it needs your signature again. Suffolk grievance guide.

Some company agreements renew automatically each year. Before you sign again, check the fee (usually a share of the first year’s savings), how long the agreement runs, and how to cancel. Our grievance companies comparison lists published fees and what to ask.