The Illinois Department of Revenue announced on Mar. 10 that Warren County has been assigned a final property assessment equalization factor, or multiplier, of 1.0000 for the 2025 tax year, according to David Harris, director of the department.
The equalization factor is used to ensure uniform property assessments across counties in Illinois. This process is important because many local taxing districts, such as school and fire protection districts, span more than one county. Without this adjustment, taxpayers with similar properties could face unequal tax burdens.
Under state law passed in 1975, most property in Illinois should be assessed at one-third of its market value. Farm homesites and dwellings follow regular assessing procedures, while farmland is assessed at one-third of its agricultural economic value and does not use the state equalization factor. In Warren County, assessments are currently at 33.30% of market value based on sales from the past three years.
The final multiplier was set after a public hearing and follows a tentative factor issued on December 10, 2025, which was also set at 1.0000. The department determines the annual multiplier by comparing recent sale prices to assessed values over a three-year period. If average assessments match one-third of market value, the multiplier remains at one; if they are higher or lower than this benchmark, the multiplier adjusts accordingly.
A change in the equalization factor does not automatically increase or decrease total property tax bills. Local taxing bodies determine tax bills based on their funding requests each year. The portion each taxpayer pays depends on their property’s assessed value and is not changed by the application of the multiplier.
The Illinois Department of Revenue works to foster an inclusive environment that values diversity and equity for employees and customers, as stated on its official site. The agency focuses on fairly administering state tax laws and efficiently collecting revenues while providing accurate information according to its official website. It also serves as a state agency dedicated to promoting diversity and equity in its operations according to its official site. The department oversees collection of state taxes and delivers reliable financial information according to its official website, operating within state taxation and revenue management as detailed on its official website.
