Cal. Wat. Code § 31146
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 the discharge of pollutants, waste or any other material within the area of the district. For such 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, shall have the right of entry to any premises on which a water pollution, waste, or contamination source, including, but not limited to, septic tanks, is located for the purpose of inspecting such source, 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 § 31146