Attention Homeowners: Notice of Tentative Assessed Value for 2021/2022 Now Available

Notice of Tentative Assessed Value is an annual statement from the Nassau County Department of Assessment (DOA). It provides every property owner with an updated value of their property. The property value shown in this notice is one factor in determining your property taxes for the 2021/2022 tax year. In addition to being posted online here Nassau County property owners will receive this notice in the mail by January 31, 2020. The notice also contains each property’s market value and the level of assessment used to calculate the tentative assessed value, along with helpful explanations of these terms.

Trending Sales Study Percentages

On January 2, 2020, the Department of Assessment published the 2021-2022 Tentative Assessment Roll, providing homeowners with an updated value of their property based on the local real estate market and trends of homes sales in each school district, over the past year. In addition to being posted online, an annual Notice of Tentative Assessment with these updated values were mailed to every homeowner. 

Note - If your property assessment increases, it does not necessarily mean your taxes increase. The property value shown in your Notice of Tentative Assessed Value is only one of several factors in determining your property taxes for the 2021-2022 tax year.

A majority of Tax Class 1 2020-2021 values were trended up by the factors in a chart you can review in the link below. Properties excluded from the trending were properties that had new construction or substantial alterations, properties that had a tax lot merger or apportionments, and properties with values exceeding $2.3 million in market value. The trends were applied to the 2020-2021 assessed values incorporating any Assessment Review Commission offers made as of December 15, 2019.

File:  Sales Trends Study Percentages by School District 2021-2022

Understanding Property Assessment Powerpoint

Newsday: Nassau reassessment fairer and more accurate, analysis shows

April 29, 2019 - Newsday published an in-depth analysis, endorsed by several industry professionals, of the first countywide property reassessment in nearly a decade. The comprehensive study concluded that the reassessment eliminated the inaccurate and unfair wide disparities among home values that developed under the Mangano Administration. The study found that the new assessments are well within every major professional standard, with experts quoted saying, “Getting much better than this is not really feasible.” For the full story, visit:


At the request of Nassau County Executive Laura Curran, the Assessment Review Commission has agreed to provide a grace period for filing a grievance until Thursday, April 30th, 2020. For more information about filing a grievance, visit


Nassau County’s Department of Assessment has published the 2020/21 Final Assessment Roll and the Assessment Review Commission has issued its Final Determinations for the 2020/21 year. ARC’s Final Determinations detail that the filing period to challenge ARC’s determinations runs from April 1st through April 30th

However, due to the current public safety and health concerns, Governor Cuomo and the NYS Unified Court System have taken measures to extend this filing period. 

The SCAR filing period began Monday, May 25, 2020 and will run through Wednesday, September 4, 2020.

County Executive Laura Curran’s Taxpayer Protection Plan

Taxpayer Protection Plan statements that show hypothetical estimated property taxes for the 2020-2021 tax year are available online at Also, an updated Frequently Asked Questions page on provides more information on the plan.

The plan will secure exemptions for class one residential property owners experiencing assessment increases that will effectively spread out any relative changes, increases and decreases, in tax burden due to the reassessment, over a five-year period.

The TPP will be effective for your 2020-2021 school and general tax bills. You will see the effects of the TPP in your school tax bill in October 2020 and your general tax bill in January 2021.”

About the Department of Assessment

The Department of Assessment is responsible for developing fair and equitable assessments for all residential and commercial properties in Nassau County on an annual basis. The County’s assessment roll includes over 423,000 properties with a value of $264 billion. It is the second largest assessing entity in the State of New York after New York City.


  • Collecting and recording relevant residential, commercial, and industrial property information.
  • Validating building permits by confirming all new construction and including the new value on the next assessment roll.
  • Maintaining property records and tax maps.
  • Answering public inquiries.
  • Assisting the public through the Department’s outreach program.
  • Processing applications for property tax exemption and the Basic and Enhanced STAR programs for qualifying Nassau County homeowners.

Schedule a Physical Inspection of Your Property

If you would like to schedule a physical inspection of your property, please send an email to or a letter to 240 Old Country Road, 4th floor, Mineola, NY 11501.  In your correspondence with the Department of Assessment, please include the address of the property you wish to have inspected and your contact information.

Verification of Tax Map Info

To File Electronically - Click Here