Cal. Water Code § 10730.2

(a) A groundwater sustainability agency that adopts a groundwater sustainability plan pursuant to this part may impose fees on the extraction of groundwater from the basin to fund costs of groundwater management, including, but not limited to, the costs of the following:
1. (1) Administration, operation, and maintenance, including a prudent reserve.
2. (2) Acquisition of lands or other property, facilities, and services.
3. (3) Supply, production, treatment, or distribution of water.
4. (4) Other activities necessary or convenient to implement the plan.
(b) Until a groundwater sustainability plan is adopted pursuant to this part, a local agency may impose fees in accordance with the procedures provided in this section for the purposes of Part 2.75 (commencing with Section 10750) as long as a groundwater management plan adopted before January 1, 2015, is in effect.
(c) Fees imposed pursuant to this section shall be adopted in accordance with subdivisions (a) and (b) of Section 6 of Article XIII D of the California Constitution.
(d) Fees imposed pursuant to this section may include fixed fees and fees charged on a volumetric basis, including, but not limited to, fees that increase based on the quantity of groundwater produced annually, the year in which the production of groundwater commenced from a groundwater extraction facility, and impacts to the basin.
(e) The power granted by this section is in addition to any powers a groundwater sustainability agency has under any other law.