California Code, Health and Safety Code - HSC § 25159.20

(a) The department shall specify, for purposes of paragraph (4) of Section 25200.6, the horizontal and vertical extent of any injection zone for an injection well. The department shall cite specific information presented in the report prepared pursuant to Section 25159.18 as the basis for specifying the extent of the injection zone and shall make a finding as to whether the injection wells' hydrogeological and operating conditions ensure that there is no potential for any migration of any hazardous waste constituents to any strata or waters of the state outside the injection zone.

(b) This section applies only to injection wells into which hazardous waste is discharged.