Sewage tank, cleaning equipment and cleaning system

The utility model discloses a sewage tank, cleaning equipment and a cleaning system. The sewage tank comprises a tank body, a sealing part and a driving mechanism, the tank body forms an opening and a storage cavity, the sealing part is arranged in the storage cavity, and the driving mechanism is connected with the sealing part and used for driving the sealing part to move so as to open or close the opening. According to the sewage tank, when the driving mechanism drives the sealing part to open the opening, sewage can flow out of the tank body, and when the driving mechanism drives the sealing part to close the opening, the sewage can be stored in the tank body. A user does not need to manually pour, sewage can be discharged through the driving mechanism, the structure is simple, and operation is convenient.