San Diego County supervisors have formally weighed in on a contentious — and increasingly costly — plan by two rural water districts to break away from a regional authority they say is too expensive. The county board voted 3-1 this week in favor of a recommendation from Supervisor Joel Anderson to support state legislation that would require approval by a majority of all voters within the regional water authority — rather than only those residents of a breakaway district. “This process would allow water customers of all (San Diego County Water Authority) member agencies to decide what is best for our region’s water future and the potential implications of their own water bills,” the former state senator told his board colleagues.