Abstract: A device for cleaning and circulating a liquid includes a one-piece plastic body having a strainer housing portion for receiving raw liquid which is to be cleaned, a filter housing portion from which cleaned liquid is to be discharged, and a pump housing portion for housing a pump and formed with a pressure outlet communicating with the filter housing portion and through which pumped liquid is delivered to the filter housing portion to be filtered therein. This pump housing portion is also formed with a suction inlet for delivering liquid to a pump housed by said pump housing portion to be pumped thereby to the pressure outlet. The filter housing portion is formed with a passage communicating on the one hand with the suction inlet and on the other hand with the strainer housing portion, so that raw liquid received in the strainer housing portion will flow therefrom through this passage to the suction inlet.