Nassau County Home Values: Census Medians, Assessed Value vs Market Value, Price Indexes

Three numbers get called “home value” in Nassau County: what Census respondents report, what the assessor records for tax purposes and what a price index tracks. They are not interchangeable. This page separates them, with the sources for each. The selling guides take the next step, starting with selling costs and the tax grievance process.

Nassau County home values in the Census data

The median value of owner-occupied homes in Nassau County is $704,400, with a margin of error of $7,791 (ACS 2024 1-year estimate). Median gross rent is $2,238, with a margin of error of $78. The county has 374,216 owner-occupied and 85,953 renter-occupied housing units in the same release. Read the figures through the Census Reporter tables rather than a listing site’s estimate.

A median is the middle home, not an average and not a price any seller will get. For income, the 2019 American Community Survey put Nassau at a median household income of $116,100 and a per capita income of $51,422.

Market value, assessed value and the level of assessment

Market value is how much a property would sell for under normal conditions. An assessment is a percentage of that market value. In communities that keep assessments at a uniform 100 percent, the assessment equals market value. State law requires properties in a municipality to be assessed at a uniform percentage of market value each year, except in New York City and Nassau County, so the uniform-level rule below does not bind the county.

The percentage of market value at which a community assesses is its Level of Assessment. A home worth $100,000 in a community assessing at 80 percent should be assessed at $100,000 × .80 = $80,000, so a $90,000 assessment would be $10,000 too high. To keep a uniform level, the assessor must analyze all properties in the municipality each year. Market values may stay the same or go down, so some properties should see a decrease in assessed value.

The tax rate is the tax levy divided by the total taxable assessed value of real property in the community. A higher assessment therefore does not automatically mean higher taxes. For how Nassau bills are built, see Nassau County property taxes.

How Nassau County sets assessments

Nassau’s Department of Assessment is the second largest assessing entity in New York State, after New York City. The county’s assessment roll includes over 423,000 properties with a value of $264 billion. The department develops fair and equitable assessments for all residential and commercial properties each year.

Its other work shapes the numbers an owner sees. It maintains property records and tax maps. It collects and records residential, commercial and industrial property information. It validates building permits and includes confirmed new construction on the next assessment roll. It also processes applications for property tax exemption. The Department of Assessment page lists these functions.

Assessors are trained to be appraisal professionals, and keeping assessments accurate and equitable is their job. The fairness of the real property tax depends on whether similar properties are treated alike.

What a house price index measures

The FHFA House Price Index is a broad measure of the movement of single-family house prices. It is a weighted, repeat-sales index, meaning it measures average price changes in repeat sales or refinancings on the same properties. It uses data that extend back to the mid-1970s from all 50 states. It incorporates tens of millions of home sales.

Those properties make the index a trend measure, not a price for a particular house. It serves as an indicator of house price trends at various geographic levels. The FHFA HPI page hosts the data files.

If you disagree with an assessment

A notice is sent to the owner with the new assessment. A homeowner who disagrees can arrange an informal conference at the assessor’s office to review the information behind the value. An owner still over-assessed after that talk has the right to file for formal review.

A tentative assessment roll lists the assessor’s estimate of market value and the exemptions for each property. Across New York, most communities publish tentative rolls on May 1. Nassau County’s grievance process has its own page: tax grievance.