Cal. Pub. Resources Code § 3152 : CALIFORNIA PUBLIC RESOURCES CODE — OIL AND GAS — OIL AND GAS CONSERVATION — WELL STIMULATION — Hydraulic fracturing defined

"Hydraulic fracturing" means a well stimulation treatment that, in whole or in part, includes the pressurized injection of hydraulic fracturing fluid or fluids into an underground geologic formation in order to fracture or with the intent to fracture the formation, thereby causing or enhancing, for the purposes of this division, the production of oil or gas from a well.