In a water purifier, a flow system includes a first channel in which liquid is filtrated in at least one of a first filter tank and a second filter tank, a second channel in which the liquid is filtrated in the second filter tank and the first filter tank is washed, and a third channel in which the liquid is filtrated in the first filter tank and the second filter tank is washed. A switching lever actuates valve mechanisms to perform switching among the first, second, and third channels such that the channels are selected cyclically in order of the first channel, the second channel, the first channel, the third channel and the first channel. The valve mechanisms work with operation of the switching lever.