Cal. Wat. Code § 31144.1
The district shall immediately do all such acts as are reasonably necessary to secure compliance with any federal, state, regional, or local law, order, regulation, or rule relating to water pollution or discharges from onsite waste water disposal systems within the area of the district. For that purpose, any authorized representative of the district, upon presentation of his credentials, or, if necessary under the circumstances, after obtaining an inspection warrant pursuant to Title 13 (commencing with Section 1822.50) of Part 3 of the Code of Civil Procedure, or with the permission of the owner, shall have the right of entry to any premises on which an onsite waste water disposal system is located for the purpose of inspecting the system, including securing samples of discharges therefrom, or any records required to be maintained in connection therewith by federal, state, or local law, order, regulation, or rule.
Ca. Water Code § 31144.1