Cal. Health and Safety Code § 111150

(a) All sources of bottled water, vended water, and water dispensed by a retail water facility shall be monitored annually for the presence of volatile organic compounds of potential public health concern, as specified by the United States Environmental Protection Agency in Tables 2 and 14 contained in Volume 50 of the Federal Register on pages 46904, 46923, and 46924 on November 13, 1985, or as reasonably specified by the department as a condition of licensure. (b) In lieu of source water monitoring required by this section, a water bottler, water vendor, or a retail water facility may document that the source monitoring required by this section is conducted by another entity approved by the department, or may comply with the treatment requirements of subdivision (c). (c) Detection in the source water of a volatile organic compound, except trihalomethanes, for which source monitoring is required pursuant to this section shall be followed immediately by a program of periodic monitoring by the water bottler, water vendor, or retail water facility to confirm the presence or absence in the source water of the volatile organic compound. If the volatile organic compound is confirmed to be present in the source water it shall be treated using granular activated carbon treatment or an equivalent treatment operated in accordance with good manufacturing practices as provided in Section 129.80 of Title 21 of the Code of Federal Regulations until the time that the concentration of the volatile organic compound does not exceed either one part per billion, or any United States Environmental Protection Agency or United States Food and Drug Administration level for drinking water, or a maximum contaminant level established by the department for bottled water. (d) The department may exempt any water bottler, water vendor, or retail water facility from the monitoring requirements of this section for any source based on a showing satisfactory to the department that the source (1) does not contain the volatile organic compound for which monitoring is required and (2) is not vulnerable to contamination by the volatile organic compound because for surface water sources the compounds are not applied, manufactured, stored, disposed or shipped upstream, and for groundwater sources, the compounds are not applied, manufactured, stored, disposed, or shipped in the groundwater recharge basin.