California Code, Water Code - WAT § 37962

If any operator of any extraction facility fails to pay a groundwater extraction charge when due, the district may charge and collect interest at the rate of 1 1/2 percent each month on the delinquent amount of the groundwater extraction charge. In addition, the district may exercise any of the provisions of Sections 75630 to 75633, inclusive, for the purpose of collecting delinquent groundwater extraction charges.