35 ILCS 200/10-23

(a) Accessibility improvements made to residential property shall not increase the assessed valuation of the property for a period of 7 years after the improvements are completed. (b) For the purposes of this Section, "accessibility improvement" means a home modification listed under the Home Services Program administered by the Department of Human Services (Part 686 of Title 89 of the Illinois Administrative Code), including, but not limited to the installation of ramps and grab-bars, widening door-ways, and other changes to enhance the independence of a disabled or elderly individual.