CA Health & Safety Code Section 106885

(a)

All persons who operate or supervise the operation of water treatment plants shall possess a valid and current water treatment operator certificate or water treatment operator-in-training certificate of appropriate grade in accordance with the regulations referred to in Section 106910.

(b)

All persons who are in responsible charge of the water distribution system of a community water system or a nontransient noncommunity water system shall possess a valid and current water distribution operator certificate of the appropriate grade in accordance with the regulations referred to in Section 106910.