How to Grieve Your Nassau County Property Taxes
Learn how Nassau County property tax grievances work, what ARC reviews, the 2027 filing window, and what a homeowner or representative actually files.
Reviewed by Chris Ambrosio, CPA · Updated October 7, 2026What does it mean to “grieve” your Nassau County property taxes?
In Nassau County, you are appealing your property’s assessment to the Nassau County Assessment Review Commission (ARC). ARC reviews the valuation; it does not set your school, town, county, or other tax rates.
1. Confirm the property and assessment information
Start by confirming the property address, parcel information, tax class, tentative assessed value, and the physical characteristics Nassau County has on file. A wrong parcel number or incorrect property record can undermine an otherwise well-prepared filing.
2. Evaluate whether the assessment is worth challenging
For residential property, homeowners commonly look at recent arm’s-length sales of reasonably similar homes, their own recent purchase price when relevant, and property-specific facts that could affect market value. The goal is not to find a neighbor who simply pays less in taxes; it is to develop evidence about the value of the property being assessed.
3. Prepare the appeal
Nassau County’s online system is AROW—Assessment Review on the Web. AROW can be used to search residential sales, file an appeal, track a filing, and review certain past and pending appeals. A representative is optional, but a representative filing for an owner needs the required authorization.
4. File before the ARC deadline
For the 2028/29 assessment, the current County calendar lists January 4, 2027 through March 1, 2027. Do not plan around the possibility of an extension. Filing early leaves time to resolve account, documentation, or authorization issues.
5. Keep the confirmation and track the case
A successful online transmission generates an appeal number. Save it. ARC’s review continues after the filing window closes, and the final determination can come months later.
Can you do this yourself?
Yes. Nassau County does not require an attorney or grievance company. GrieveItNow is for homeowners who understand that option but would rather have the property research, preparation, authorization, filing, and status tracking handled for them for a flat $99 fee.
Official filing dates and procedural references are based on current Nassau County Assessment Review Commission and Department of Assessment materials. County notices and rules control if they change. Educational information is not a guarantee of a reduction.
Reviewed by Chris Ambrosio, CPA
A Certified Public Accountant with over 13 years of financial experience. Chris spent more than six years at a Big Four accounting firm auditing financial services companies, followed by a year in private equity before nearly six years in the real estate industry as a Senior Manager of Accounting. He brings institutional-grade financial analysis to every property tax grievance filing.