Cal. Fish & Game Code § 5650

(a) Except as provided in subdivision (b), it is unlawful to deposit in, permit to pass into, or place where it can pass into the waters of this state any of the following:
1. (1) Any petroleum, acid, coal or oil tar, lampblack, aniline, asphalt, bitumen, or residuary product of petroleum, or carbonaceous material or substance.
2. (2) Any refuse, liquid or solid, from any refinery, gas house, tannery, distillery, chemical works, mill, or factory of any kind.
3. (3) Any sawdust, shavings, slabs, or edgings.
4. (4) Any factory refuse, lime, or slag.
5. (5) Any cocculus indicus.
6. (6) Any substance or material deleterious to fish, plant life, mammals, or bird life.
(b) This section does not apply to a discharge or a release that is expressly authorized pursuant to, and in compliance with, the terms and conditions of a waste discharge requirement pursuant to Section 13263 of the Water Code or a waiver issued pursuant to subdivision (a) of Section 13269 of the Water Code issued by the State Water Resources Control Board or a California regional water quality control board after a public hearing, or that is expressly authorized pursuant to, and in compliance with, the terms and conditions of a federal permit for which the State Water Resources Control Board or a California regional water quality control board has, after a public hearing, issued a water quality certification pursuant to Section 13160 of the Water Code. This section does not confer additional authority on the State Water Resources Control Board, a California regional water quality control board, or any other entity.
(c) It shall be an affirmative defense to a violation of this section if the defendant proves, by a preponderance of the evidence, all of the following:
1. (1) The defendant complied with all applicable state and federal laws and regulations requiring that the discharge or release be reported to a government agency.
2. (2) The substance or material did not enter the waters of the state or a storm drain that discharges into the waters of the state.
3. (3) The defendant took reasonable and appropriate measures to effectively mitigate the discharge or release in a timely manner.
(d) The affirmative defense in subdivision (c) does not apply and may not be raised in an action for civil penalties or injunctive relief pursuant to Section 5650.1, or in any other civil action that alleges a violation of this section resulting from unlicensed cannabis cultivation.
(e) The affirmative defense in subdivision (c) does not apply and may not be raised by any defendant who has on two prior occasions in the preceding five years, in any combination within the same county in which the case is prosecuted, either pleaded nolo contendere, been convicted of a violation of this section, or suffered a judgment for a violation of this section or Section 5650.1. This subdivision shall apply only to cases filed on or after January 1, 1997.
(f) The affirmative defense in subdivision (c) does not apply and may not be raised by the defendant in any case in which a district attorney, city attorney, or Attorney General alleges, and the court finds, that the defendant acted willfully.