NASSAU COUNTY HOMEOWNER RESOURCES
Nassau County tax grievance deadline
Put the filing window on your calendar, then give yourself time to understand the assessment you want reviewed.
The published ARC filing window is January 4–March 1, 2027. Confirm the dates on Nassau County’s appeal instructions before filing.
Which assessment are you appealing?
The County issues an assessment each year, and its appeal deadline comes before the resulting tax bills. A pending appeal from a previous year does not replace a new-year application. Check the assessment year in the official filing system. Our process guide sets the filing window in the context of the full review cycle.
Prepare a small review folder
Our suggested checklist keeps your research organized:
- Save the record you reviewed, its year, and the date you retrieved it.
- Write down property details you want to verify, such as living area or building type.
- Keep notes on each sale you considered, including differences from your home.
- Gather any existing representation agreement so you know what you have already authorized.
Start with your property check and use our assessment guide to work through the figures.
Filing yourself or using a representative
ARC accepts online applications without a filing fee; an attorney is not required. Avoid duplicate applications or authorizations. If a representative or condominium board is filing for you, check that arrangement before filing independently. See the County’s instructions for details.
Keep separate assessments in view
A village assessment may have a different appeal process. Check with the local assessor rather than assuming the ARC deadline applies. The County FAQ explains the distinction.
Keep a record of your next step
Once you use the official filing system, save its confirmation and any documents you submitted. A Good Grieves lookup or guide download does not file anything with the County.
BEFORE THE WINDOW OPENS
Remind me before the filing window opens.
The published ARC filing window is January 4–March 1, 2027. Leave your email and we’ll send one reminder before it opens.
We’ll only use this to send that reminder. No newsletter, no sharing, and nothing is filed with the County.Keep reading
How the tax grievance process works
The full sequence, from the tentative assessment roll through ARC’s review and Small Claims Assessment Review.
Choosing comparable sales
Which nearby sales support an appeal, which differences matter, and why a neighbor’s lower bill is not evidence.
See how it applies to your home
Review your available County record alongside what you’ve learned.
Check my property