NASSAU COUNTY HOMEOWNER RESOURCES
Just bought or built a home in Nassau County? What your assessment means
A closing statement tells you what you paid. The County’s record tells you what it thinks the house is worth, and when. New owners are often surprised by the difference, and the first year is the right time to sort it out.
Two separate tasks: check the County’s record of your new home, and apply in your own name for the exemptions you qualify for. Neither happens automatically when the deed is recorded.
Why the County’s number and your price differ
Nassau County values every property for an assessment year, and that valuation is tied to the County’s calendar rather than to your closing. If the market moved between the County’s reference point and your purchase, the two figures will differ even if both are reasonable. The County’s tax bills are also calculated from the assessed value — a fractional assessment level applied to market value — so the number on a bill is not a sale price either. Our assessment guide walks through the three figures.
The record itself can also lag the house. If you built new or substantially renovated, the record may still describe what stood there before. If you bought an older home, the record may omit work the seller did, or list a feature that no longer exists. Read the recorded property details against the home you actually own before deciding whether the value is wrong.
Common questions
I paid less than the County’s market value. Is my assessment wrong?
Not necessarily, but it is worth checking. Nassau County defines market value as the most probable price at which a property would sell under ordinary circumstances, and it estimates that value for an assessment year rather than for your closing date. A sale is strong evidence, but a sale under unusual conditions, or a record with outdated property details, can explain a gap.
The definition is on the County FAQ. Whether your own sale meets it depends on the circumstances — a purchase from a relative, an estate, or a lender is a real transaction and still a weak comparable. Our guide to choosing comparable sales explains why.
Do the previous owner’s exemptions carry over to me?
Exemptions describe the owner and household, not the house. New York State states that the STAR exemption is no longer available to new homeowners, who register for the STAR credit with the State instead. Other partial exemptions are applied for through Nassau County’s Department of Assessment based on your own eligibility.
Register for the STAR credit at New York State’s STAR page, and check the State’s eligibility rules, which require the home to be the primary residence of an eligible owner. For exemptions based on age, income, disability, or military or volunteer service, use the County’s exemptions information. Our exemptions guide separates these from an appeal.
When can a new owner file a grievance?
In the same window as everyone else. The published ARC filing window for the 2028–29 assessment year is January 4–March 1, 2027. Nassau County states there is no fee to file with ARC and that you are not required to use an attorney. Each year’s assessment is appealed on its own.
Confirm the dates on Nassau County’s appeal instructions. If you closed after a window ended, the assessment for that year is already set, and your first opportunity is the next tentative roll — see our deadline guide.
What if the seller had a tax grievance representative?
Find out before you file. A representative’s authorization or a pending application from the seller can cover the same assessment year you want to appeal, and you should avoid duplicate applications or overlapping authorizations. Ask your closing attorney or the seller which years any agreement covers, and keep a copy of the answer.
The County’s appeal instructions describe filing for yourself and filing through a representative. If a firm contacts you after closing about an appeal it says it has already filed, ask for the appeal number and the authorization it is relying on before you sign anything.
What to do in your first year
- Look up the record. Check your property, then open the County’s own record and note the assessment year, the recorded details, the market value, and the assessed value. Label your notes with the date.
- Register and apply for exemptions in your own name. Start with the STAR credit, then review the County’s exemptions information for anything else your household qualifies for. Deadlines and forms differ by program.
- Ask about pending appeals and authorizations. Confirm whether the seller, a representative, or a condominium board has filed or authorized anything covering the assessment year you care about.
- Calendar the filing window. The published window is January 4–March 1, 2027. The deadline guide includes a downloadable reminder.
- Decide whether the value needs an appeal. A documented inventory error and an argument about value are different cases; gather the right evidence for the one you have.
Keep the purchase file
The documents from your closing are the best description of the home as it actually is: the contract and closing statement, the lender’s appraisal, the inspection report, and — for new construction — permits, the certificate of occupancy, and construction costs. Keep them together. If you decide to appeal, they are the materials that support what you say about the property, and if you do not, they are the baseline for reading next year’s tentative roll.
A village or city assessment is separate
If your new home is in a village, the City of Long Beach, or the City of Glen Cove, there may be a separate local assessment with its own appeal process. The County FAQ explains the distinction; confirm with the local assessor rather than assuming the County calendar covers everything.
Start with the record, not the bill
A higher-than-expected bill is a reason to look, not a conclusion. Look up your property, verify the details, and read how the process works before deciding anything. Good Grieves does not file appeals or exemption applications through this website, this page is general information rather than legal or tax advice, and savings are never guaranteed.
Keep reading
Property tax exemptions and STAR
How STAR, Enhanced STAR, and other partial exemptions differ from an assessment appeal, and where to apply.
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