Cal. Wat. Code § 1433.5
A permit issued under this article shall not result in the creation of a vested right, even of a temporary nature. The permit is subject, at all times, to modification or revocation at the discretion of the board, after the permittee has adequate notice and an adequate opportunity to be heard concerning any proposed modification or revocation. The authorization to divert and use water under the permit shall automatically expire five years after the authorization takes effect, unless an earlier date is specified or the temporary permit is revoked, and shall be junior in priority to any subsequent appropriation not subject to this chapter. The five-year period does not include any time required for monitoring, reporting, or mitigation before or after the authorization to divert or use water under the permit. The five-year period is a limitation on the authorization to divert and not a limitation on the authorization for beneficial use of the water diverted to underground storage.
Ca. Water Code § 1433.5