On the control panel. According to the official information of Bi Shuiyuan, the switch of Bi Shuiyuan water purifier is on the control panel. When using, plug in the power supply of the water purifier, select the switch water source option on the control panel, and click according to your own choice when closing. Bi Shuiyuan water purifier is a high-tech water purifier independently developed by Beijing Bi Shuiyuan Water Purification Technology Co., Ltd.