Water tank, base station and cleaning system

The water tank, the base station and the cleaning system are characterized in that the water tank is applied to the base station, the base station comprises a base station body, the water tank is detachably connected with the base station body, a clear water cavity and a sewage cavity are formed in the water tank, and a clear water inlet communicated with the clear water cavity and a sewage outlet communicated with the sewage cavity are formed in the water tank; wherein the clean water inlet is used for being communicated with an external water source device, and a first valve is arranged between the clean water inlet and the external water source device, so that clean water is supplied into the clean water cavity when the first valve is opened; the sewage outlet is used for being communicated with the outside, and a second valve is arranged between the sewage outlet and the outside, so that sewage in the sewage cavity is discharged to the outside when the second valve is opened. The water tank can be detache