a schematic detached view of the second embodiment in fig4 the water inlet 121 of the water inlet end 12 of the water pump 1 is assembled with the filtration device 2 while the outlet joint 22 of the filtration device 2 is secured to the water inlet end 12 referring to fig5 a schematic sectional view of the third embodiment of the present invention is shown in the third embodiment of the present invention each of the water outlet end 11 and the water inlet end 12 of the water pump 1 is assembled with a filtration device 2 in such a manner that the water outlet end 11 is assembled with the inlet joint 23 of the filtration device 2 and the outlet joint 22 of the filtration device 2 is connected to the water pipe a at the water reservoir side while the water inlet end 12 of the water pump 1 is assembled with the outlet joint 22 of the filtration device 2 and the inlet joint 23 of the filtration device 2 at the other end is connected to the water pipe a at the water supply side as shown in fig1 water flowing through the water pipe a at the water.