210 ILCS 115/9.4

An adequate supply of water of safe, sanitary quality, approved by the Department shall be furnished at each park. Where water from other sources than that supplied by a city or village is proposed to be used, the source of such supply shall first be approved by the Department. Each mobile home shall have a connection to a public water system, a semi-private water system, or a private water supply constructed in accordance with the requirements of the Illinois Water Well Construction Code or the Surface Source Water Treatment Code.