70 ILCS 2605/11.13
Bond, with sufficient sureties, in such amount as shall be deemed adequate by the director of procurement and materials management not only to insure performance of the contract in the time and manner specified in said contract but also to save, indemnify and keep harmless the sanitary district against all liabilities, judgments, costs and expenses which may in anywise accrue against said sanitary district in consequence of the granting of the contract or execution thereof shall be required for all contracts relative to construction, rehabilitation or repair of any of the works of the sanitary district and may be required of each bidder upon all other contracts in excess of the mandatory competitive bid threshold when, in the opinion of the director of procurement and materials management , the public interest will be better served thereby.
In accordance with the provisions of "An Act in relation to bonds of contractors entering into contracts for public construction", approved June 20, 1931, as amended, all contracts for construction work, to which the sanitary district is a party, shall require that the contractor furnish bond guaranteeing payment for materials and labor utilized in the contract.
70 ILCS 2605/11.13