San Mateo: Wastewater Treatment Plant Operator III (19903900) 1. Do you possess at least a valid Grade III Wastewater Treatment Plant Operator Certificate issued by the State of California or higher? Please attach or upload a copy of your Grade III WWTP Operator Certificate with your employment application in CalOpps. Yes No 2. Do you have at least three years of progressively responsible experience in the operation of a wastewater treatment plant? Yes No