625 ILCS 5/18a-302
It shall be unlawful for an owner or other person in lawful possession or control of private property to remove or employ a commercial relocator to remove an unauthorized vehicle from such property unless written notice is provided to the effect that such vehicles will be removed, including the name, address and telephone number of the appropriate commercial vehicle relocator, if any. Such notice shall consist of a sign, posted in a conspicuous place in the affected area, of a size at least 24 inches in height by 36 inches in width. Such sign shall be at least 4 feet from the ground but less than 8 feet from the ground and shall be either illuminated or painted with reflective paint, or both. Such sign shall state the amount of towing charges to which the person parking may be subject. This provision shall not be construed as prohibiting any unit of local government from imposing additional or greater notice requirements.
No express notice shall be required under this Section upon residential property which, paying due regard to the circumstances and the surrounding area, is clearly reserved or intended exclusively for the use or occupation of residents or their vehicles.
625 ILCS 5/18a-302