Will County has been issued a tentative property assessment equalization factor of 1.0000, according to Illinois Department of Revenue Director David Harris.

The property assessment equalization factor, commonly called the “multiplier,” is used to ensure uniform property assessments among Illinois counties, as required by state law.

Equalization is important because many of the state’s 6,600 local taxing districts, such as school, fire protection and junior college districts, overlap county lines, according to the announcement from the Illinois Department of Revenue.

Without equalization, taxpayers with comparable properties in different counties could face inequitable tax burdens, the release stated.

Illinois law requires property to be assessed at one-third of its market value. Farm property is assessed differently, with homesites and dwellings subject to regular assessing and equalization procedures, while farmland and farm buildings are valued according to productivity-based standards, according to the release.

The annual equalization factor is determined by comparing the sales prices of properties sold over the past three years with the assessed values set by the county supervisor of assessments or county assessor.

When the three-year average level of assessment equals one-third of market value, the factor is 1.0000.

Assessments in Will County are currently at 33.46% of market value, based on sales from 2022, 2023 and 2024. The tentative factor applies to 2025 taxes payable in 2026. Last year’s equalization factor for Will County was also 1.0000, according to the release.

“The tentative factor may change if the County Board of Review makes significant assessment adjustments or if additional data shows that the Department of Revenue’s estimates should be revised,” Illinois Department of Revenue stated.

A change in the equalization factor does not necessarily mean property tax bills will rise or fall. Tax bills are based on the levies set by local taxing bodies. If those levies remain unchanged from the previous year, total property taxes will not increase even if assessments do.

The equalization factor only affects how property values are standardized across counties; it does not alter an individual taxpayer’s proportionate share of the overall tax burden, according to the release.