thank you Darin for the info:
(625 ILCS 45/57) (from Ch. 95 1/2, par. 3157)
Sec. 57. Restricted areas. No person shall operate a watercraft within a water area that has been clearly marked by buoys or some other distinguishing device as a bathing, fishing, swimming or otherwise restricted area by the Department or a political subdivision of the State or by an owner or lessee of property in accordance with his or her rights to the use of the property, except in the manner prescribed by the buoys or other distinguishing devices. This Section shall not apply in the case of an emergency, or to patrol or rescue craft.
No person shall operate a watercraft within 150 feet of a public launching ramp owned, operated or maintained by the Department or a political subdivision of the State at greater than a "No Wake" speed as defined in Section 512 of this Act. Posting of the areas by the Department or a political subdivision of the State is not required.
The Department and other political subdivisions of the State may, within their discretion and after issuing an administrative rule in accordance with the Illinois Administrative Procedure Act, designate certain areas by proper signs to be bathing, fishing, swimming or otherwise restricted areas, or eliminate, alter or otherwise modify existing areas. The Department or a political subdivision of the State shall further have the authority in order to fully carry out the provisions of this Act to place signs, beacons and buoys in designated areas controlling the flow of traffic.
It shall be unlawful for any person to deface, move, obliterate, tear down, or destroy, in whole or in part, or attempt to deface, move, obliterate, tear down or destroy any buoys or signs posted pursuant to the provisions of this Act, except as authorized by the Department.
(Source: P.A. 92651, eff. 71102.) (625 ILCS 45/512) (from Ch. 95 1/2, par. 3157.5)
Sec. 512. A wake is defined as a movement of the water created by a boat underway great enough to disturb a boat at rest, but under no circumstances shall a boat underway exceed 5 miles per hour while in a posted "No Wake" area. "No Wake" areas shall be clearly posted with buoys or appropriate signs except as provided in Section 57 of this Act. All buoys or signs posting "No Wake" areas shall meet the specifications as prescribed by the United States Coast Guard or the Illinois Department of Natural Resources.
(Source: P.A. 89445, eff. 2796.)