Cal. Water Code § 4104

If the owner of any conduit refuses or neglects to construct and maintain the diversion dam or works, the headgate, or the measuring devices provided for in this article after 30 days’ notice by the department so to do, the watermaster may close the conduit, and it shall not be opened or any water diverted from the source of supply until the requirements of the department as to the diversion dam or works, the headgate, or the measuring devices have been complied with.