California Code, Health and Safety Code - HSC § 4742.1

It may contract with any district, city, governmental agency, or person, for the handling, treatment or disposal by the district of refuse, sewage, or industrial wastes originating within the district or county or within areas outside of the district or county when, in the judgment of the district board, it is for the best interest of the district to do so, upon such terms and conditions as may be agreed upon; provided, that the contract shall be for such term as agreed upon, but in no event for a term in excess of 50 years, or for such time as in the judgment of the district board the district shall have the capacity for handling, treatment or disposal of such refuse, sewage, or industrial wastes.