70 ILCS 2605/11.4
Contracts which by their nature are not adapted to award by competitive bidding, such as, but not only, contracts for the services of individuals possessing a high degree of professional skill where the ability or fitness of the individual plays an important part, contracts for the purchase or sale of utilities and contracts for materials economically procurable only from a single source of supply and leases of real property where the sanitary district is the lessee shall not be subject to the competitive bidding requirements of this Act. The sanitary district is expressly authorized to procure from any federal, state or local governmental unit or agency such surplus materials, as may be made available without conforming to the competitive bidding requirements of this Act. Regular employment contracts, whether classified in civil service or not, shall not be subject to the competitive bidding requirements of this Act.
70 ILCS 2605/11.4