In addition to other powers and authorities any irrigation district now or hereafter organized under the laws of Idaho and having a contract or hereafter contracting with the United States under the Federal Reclamation Law (being the act of June 17, 1902 (32 Stat. 388) and acts amendatory thereof or supplemental thereto) may (a) contract with the United States or an agency of the state of Idaho for the construction, operation and maintenance of a domestic or irrigation water system, and (b) enter into such other obligations and do such other things as are incidental to the construction and operation and maintenance of such system and (c) make provisions for the operation and maintenance of a garbage disposal program for the benefit of the residents. The cost of operation and maintenance of such garbage disposal program shall be paid from the district’s current expense fund. Service through such system may be provided both to lands within the district and to other lands that the district’s board of directors determines can be served feasibly and economically. Any irrigation district contracting with an agency of the state of Idaho shall not be required to have a contract with the United States under the Federal Reclamation Law, as cited above.