Whenever a city or town located wholly or in part within a water district shall enter into a contract with the commissioners of a water district providing that the city or town shall take over all of the operation of the facilities of the district located within its boundaries, such area of said water district located within said city or town shall upon the execution of said contract cease to be a part of said water district and the inhabitants therein shall no longer be permitted to vote in said water district. The land, however, within such city or town shall remain liable for the payment of all assessments, any lien upon said property at the time of the execution of said agreement and for any lien of all general obligation bonds due at the date of said contract, and the city shall remain liable for its fair prorated share of the debt of the area for any revenue bonds outstanding as of said date of contract.