Cal. Gov. Code § 6526

Notwithstanding any other provision of law, any public agency that is a member of the South East Regional Reclamation Authority, the Aliso Water Management Agency, the South Orange County Reclamation Authority, or the San Juan Basin Authority may exercise any power granted to those entities by any of the joint powers agreements creating those entities, whether or not that public agency is a signatory to any of these joint powers agreements granting that power or is otherwise authorized by law to exercise that power, for the purpose of promoting efficiency in the administration of these joint powers entities.