A water cleaner, including a housing and a filter mechanism. Two ends of the housing are provided with a first inlet and a first outlet, respectively. The filter mechanism is arranged in the housing. A first end and/or an outer circumference of the filter mechanism are/is provided with a second inlet, and a second end is provided with a second outlet. The sewage flows into the housing through the first inlet and flows towards the filter mechanism to be filtered. The obtained clean water flows into the filter mechanism through the second inlet and flows out of the housing through the second outlet and the first outlet in sequence. The first end of the filter mechanism is close to the first inlet, and the second end is close to the first outlet.