Abstract: A portable cleaning apparatus for removing solids and particulate material from water in the basin of a cooling tower and having a trailer with a frame supporting a platform and a plurality of wheels for enabling said trailer to be towed from place to place, a power driven pump means mounted on said platform and having a suction side adapted to be placed into communication with water contaminated with solids in the basin of a cooling tower, a filter device arranged on said platform and including a filter medium therein, an inlet for liquid influent connected to the pump outlet and an effluent outlet downstream of the filter medium, the filter medium being so constructed and arranged as to retain solid particles thereon whose diameter is in excess of 0.