How to appeal your own property assessment with Nassau County, step by step. It costs nothing to file for yourself, and you do not need a lawyer.
Your share of school, county and town taxes depends on your assessed value, a number the county sets for your home each January. If that number is too high compared with what your home would actually sell for, you pay more than your fair share.
Nassau states its home values at 0.1% of market value. But ARC's own published level for 2027/28 filings is lower, 0.054%. In plain English: to see what the county is really saying your home is worth, divide your assessed value by 0.00054, not by 0.001. If that number is higher than your home would sell for, that gap is what a grievance fixes.
Source: ARC FAQ, "Level of assessment".
This cycle sets the assessment used for your October 2028 school tax bill and your January 2029 general (county and town) tax bill.
| January 4, 2027 | Department of Assessment publishes the 2028/29 tentative assessment roll. ARC filing opens. |
| March 1, 2027 | Last day to file your appeal with ARC. ARC's FAQ says there are no extensions. |
| March 2, 2027 to March 31, 2028 | ARC reviews appeals. Offers of reduction go out by email during this period. |
| March 31, 2028 | ARC sends final determination letters. |
| April 3, 2028 | Final assessment roll published, including ARC's changes. |
| May 1, 2028 | Last day to file for court review, including Small Claims Assessment Review (SCAR). |
Source: ARC Assessment Review Calendar and the 2028/29 ARC brochure.
AROW (one R, short for Assessment Review on the Web) is ARC's free online filing system. Filing online gets you an instant confirmation email, lets you track your appeal, and lets you answer offers online. Plan on 30 to 45 minutes the first time.
Go to nassaucountyny.gov/arc/arow and click "Register With ARC." Use an email you check often, because offers come by email. Confirm the email ARC sends you (check spam), then log in. The Sales Locator and public lookups work without registering, but you need an account to file.
Open "Sales Locator" and search by address or parcel ID (section, block, lot). Type the house number and the main word of the street name. Leave off "Street," "Ave," and so on, because the system uses its own abbreviations. Check that the county's description of your home (square footage, bedrooms, bathrooms) looks right. If it is wrong, note it for Part D and call the Department of Assessment at (516) 571-1500.
Click "Find Sales." AROW lists recent sales of similar homes nearby and adjusts each price for differences like lot size, square footage and bathrooms. A simple, fair approach is to use the first five results the system gives you. That way you are not cherry-picking, and they are usually closest to your home.
Select your comps and continue. AROW shows an adjusted sale price for your comps (it may be labeled weighted or average). Write it down. Also write down the county's value for your home: your assessed value, or the market value figure AROW shows. Put both into the calculator below. It gives you the Part B number and Part D statement you need for steps 5 to 9.
Enter the numbers from the Sales Locator. Results fill in as you type. Nothing you type leaves your browser.
Your estimate of full market value. Type it into Part B exactly as shown: no dollar sign, no commas, no decimals.
Paste this into the "Other facts" box in Part D, then add anything specific about your home.
Find your current tax bills on the county's Land Record Viewer (look up your property, then check the school and general tax information). Enter the yearly totals below. Leave out village taxes; a county appeal does not change them.
With your calculator results ready, go back to AROW, choose to file an appeal, and work through the form one part at a time.
Confirm the parcel ID and address. List every owner on the deed. Choose to get communications from ARC electronically so offers reach your inbox.
This is the most important box. The form asks for your full market value: what your home would sell for today. ARC then multiplies that by the correct level of assessment itself. Enter the Part B number from the calculator, which is simply the market value your comps point to.
Required. Pick "Self" as the representative if you are filing for yourself, and double-check your email and phone.
Part D asks about your home and has an "Other facts" box. Paste in the statement the calculator writes for you, and add anything that hurts value (busy road, flooding, needed repairs, errors in the county's record). Answer the construction questions truthfully. Part E is where comparable sales go; make sure your five comps are listed, and attach photos or documents if you have them.
Check who is certifying (usually "Owner"), review everything, and click submit one time only. Wait for the confirmation screen and save your appeal number. You should also get an email confirmation.
ARC reviews appeals from March 2, 2027 through March 31, 2028, so an offer can arrive any time in that window. Offers have a response deadline. You must tell ARC whether you accept or reject; if you let it lapse, you can lose the reduction. Check your inbox and spam folder often, and log into AROW to respond.
When you accept online, you get an email receipt and a PDF in AROW. ARC has short videos on responding to an offer, responding to a preliminary determination, and responding to a second review settlement offer.
Compare the offer with what your comps support (the calculator's "assessed value your comps support"). ARC's settlement calculator shows the percentage reduction of any offer.
After the final roll comes out in April 2028, look up your property to confirm an accepted reduction was applied.
If you own and live in a one, two or three family home (or a Class 1 condo) used only as a residence, and you did not accept an ARC offer, you can ask a court hearing officer to review it. It does not require a lawyer.
Bought recently: your purchase price is strong evidence of market value and ARC will see it. Part B asks whether the home sold in the last 12 months. If you paid less than the county implies, say so in Part D and attach the closing statement.
Two-family home: if the Sales Locator shows few two-family sales, use the closest one-family comps and explain the differences in Part D.
Most incorporated villages in Nassau set their own assessments for village taxes, separate from the county. The cities of Long Beach and Glen Cove do too. ARC says plainly that a county appeal does not apply to your village or city assessment. So winning at ARC can lower your school, county and town taxes, but not your village tax.
To appeal the village assessment, you file a separate grievance with the village using New York State Form RP-524. The village Board of Assessment Review usually meets on Grievance Day, typically the third Tuesday of February, and the form is usually due by then. Dates vary, so call your village clerk early in January to ask whether the village assesses property and when its Grievance Day is.
A grievance fixes your home's value. Exemptions are a separate way to lower your bill.
Deadline: the Department of Assessment's current exemption guide says applications for the 2027-28 property tax year must be received by January 4, 2027. Income limits and details are in that exemption guide. Villages need their own exemption applications.
Assessed value = county market value ÷ 1,000 (the Assessor's stated 0.1%) Value the county implies = assessed value ÷ ARC level of assessment Assessed value your comps support = comps value × ARC level of assessment Part B = comps value (your full market value estimate)
Tick these off as you go. (This list resets when you leave the page.)