A district which has acquired or constructed or which proposes to acquire or construct any sewage disposal facilities, may contract with any public agency or with any person, firm, or corporation for the use of any such sewage disposal facilities by any such public agency, or for the flowage, treatment, or disposal of sewage from any area designated by the person, firm, or corporation so contracting, upon such terms and conditions as may be provided in the contract.
Ca. Pub. Util. Code § 16876