Every governmental entity shall be empowered to enter into contracts with other governmental entities for the collection of sewage, for the disposal of sewage, and for the treatment of sewage, and to that end shall be jointly and severally empowered to construct, operate, maintain, enlarge and improve sewer facilities designed for use by the parties to the contract. Such contract may provide for the joint ownership of the sewer facilities or for the ownership of such facilities by any of the contracting parties, provided that, in such event, the remaining parties shall be empowered to utilize such sewer facilities to the extent provided for in the contract.