NASSAU COUNTY HOMEOWNER RESOURCES
The tentative assessment roll: what to check when it is published
The tentative roll is the County’s opening figure, not its final word. The weeks after it appears are when a careful homeowner reads the record line by line.
The published ARC filing window is January 4–March 1, 2027. Confirm the current dates on Nassau County’s appeal instructions before you plan around them.
What the tentative roll is
Nassau County issues a new assessment for every property each year. The version published first is tentative: it is the figure the County proposes to use, and it is the figure you appeal. The Assessment Review Commission’s filing window follows publication, ARC’s review happens after that, and only then does the County publish the assessment roll it will actually bill from — usually April 1, according to the County. Our process guide puts those steps in order.
That sequence matters because it sets your timetable. The record you can read in January is the one that will drive tax bills later, and the window for saying it is wrong closes on the published deadline, not when the bills arrive.
Common questions
When is the Nassau County tentative assessment roll published?
Nassau County publishes a new tentative assessment for every property each year, and the Assessment Review Commission filing window follows it. The published ARC filing window for the 2028–29 assessment year is January 4–March 1, 2027. Confirm the current dates on the County’s appeal instructions before you rely on them.
We deliberately do not restate the County’s publication schedule here, because it is the County’s calendar to publish and ours to check. Open Nassau County’s appeal instructions for the current cycle, and look up your own record rather than waiting to hear about it secondhand.
What should I check on my tentative assessment?
Check the property address and parcel identifier, the recorded property details, the County’s market value, the assessed value and the level of assessment used to calculate it, and any exemptions shown. Note the assessment year and the date you looked.
The six-point check below walks through each item. Our assessment guide explains what the figures measure.
How does the tentative roll year relate to my tax bills?
Each year’s assessment is labeled by the tax year it will be used for, which is later than the year it is published. The assessment appealed in the January 4–March 1, 2027 filing window is for the 2028–29 assessment year. The County states that the Department of Assessment publishes the assessment roll, usually April 1, and tax bills based on it arrive after that. Confirm the exact mapping on the County FAQ.
Keep the label straight when you compare records: a bill you are paying now was calculated from an earlier assessment, not from the tentative figure you are reviewing. The County FAQ explains how assessments feed into later bills.
What if I miss the filing window?
Each year’s assessment is appealed on its own schedule, so a missed window means waiting for the next tentative assessment. A pending appeal from a previous year does not replace a new application.
Put the dates on your calendar now. Our deadline guide has a preparation checklist and a downloadable reminder.
A six-point check of your record
Open your property’s record in the County’s system, then work through these in order and write down what you find. Our property checker shows the available County figures alongside nearby records, but the County’s own record is the one that counts.
- Address and parcel identifier. Confirm you are looking at your property and not a neighboring lot or a unit with a similar address. Note the section, block, and lot as the County records them.
- Property details. Read the recorded inventory — living area, style, construction year, and the like — against the house you actually own. An addition the record does not show, or a feature that no longer exists, is exactly the kind of thing worth noting.
- Market value. The County defines this as “the most probable price at which a property would sell if offered for sale under ordinary circumstances.” Ask whether that figure is plausible for your home in its actual condition.
- Assessed value and level of assessment. The assessed value reflects a fractional assessment level applied to market value, so it is not a sale price. Check that the level shown is the one the County publishes for your property class.
- Exemptions. Confirm any exemptions you expect are reflected, and remember that the STAR credit comes from New York State rather than appearing on the County record. Our exemptions guide explains the difference.
- The year and the date you looked. Label your notes with the assessment year and the retrieval date. Records change between the tentative and final roll, and an unlabeled screenshot is hard to use later.
Separate the facts from the argument
A wrong square-footage figure is a fact you can document. A market value you believe is too high is an argument you have to support with evidence, usually comparable sales. Keep the two lists separate, because they call for different preparation: the first needs documents that describe your home, the second needs research into what similar homes sold for. Our guide to choosing comparable sales covers the second list.
Then decide whether to file
If everything checks out, you are done for the year, and you have a labeled record to compare against next time. If something does not, the County accepts appeals during the published window, states there is no fee to file with ARC, and does not require an attorney. Read the deadline guide for a checklist and confirm the County’s current instructions before you file. Good Grieves does not file anything with the County through this website, and savings are never guaranteed.
Keep reading
Nassau County tax grievance deadline
The published 2027 filing window, a preparation checklist, and where to confirm current instructions.
Understanding your Nassau County assessment
Make sense of market value, assessed value, and tax bills before comparing your home with nearby properties.
See how it applies to your home
Review your available County record alongside what you’ve learned.
Check my property