A rotatable filter includes a base unit, a rotating unit and an external unit. The base unit includes a seat having a through hole, and a container disposed on the seat, corresponding in position to the through hole and having a drainage space. The rotating unit is disposed on the base unit and includes a rotating disc mounted on the seat and having a rotating part that is rotatable relative to the seat, a converging seat connected to the rotating part and having a collecting space that is in fluid communication with the drainage space, a plurality of guiding pipes extending into the converging seat, and a plurality of valve seats respectively disposed on the guiding pipes. The external unit is connected to the rotating unit and includes a rotating cover disposed above the seat, and a plurality of filtering modules disposed on the rotating cover.