Any work or other public improvement which is not to be paid for in whole or in part by special assessment or special taxation and does not involve a contract with the federal government or any agency thereof, and all purchases of and contracts for supplies, materials and services not involved in public works projects shall, except as specifically provided herein, be based whenever possible on competitive bids. (Ord. 977 § 1 (part), 1992: prior code § 2-4-8(A))