Cal. Food & Agric. Code § 13148

(a) In order to more accurately determine the mobility and persistence of the pesticides identified in the Groundwater Protection List, and to determine if these pesticides have migrated to groundwaters of the state, the director shall conduct soil and groundwater monitoring statewide in areas of the state where the pesticide is primarily used or where other factors identified pursuant to Section 13143 and the Groundwater Protection List, including physicochemical characteristics and use practices of the pesticides, indicate a probability that the pesticide may migrate to the groundwaters of the state. The department shall monitor for the active ingredient, other specified ingredient, or degradation product of the pesticide listed in the Groundwater Protection List. The monitoring shall commence within one year after the pesticide is placed on the Groundwater Protection List and shall be conducted in accordance with standard protocol and testing procedures established pursuant to subdivision (b). Monitoring programs shall replicate conditions under which the pesticide is normally used in the area of monitoring. In developing a monitoring program, the director shall coordinate with other agencies that conduct soil and groundwater monitoring.

(c) The director shall report all monitoring results to the State Department of Public Health and the board.