Whenever the governing body of the city shall deem that an emergency exists by reason of a shortage of water supply and that in order to properly protect and to fully utilize the supply of water for essential uses such as household consumption, maintenance of health and sanitation facilities and the operation of essential businesses, the governing body shall have power to declare an emergency to exist and to prohibit during the period of the emergency, the use of water for nonessential uses and to promulgate and enforce conservation measures limiting the permissible use of water from the city water supply for essential cases only. Such emergency shall be deemed to continue until it is declared by the governing body to be ended. (Prior code § 17-301)