A pump-and-filter assembly for use in a pond, pool, or fountain. The pump unit creates a flow of water into an intake port and out through a discharge port and a filter unit mounted in front of the pump unit for filtering water flowing through the pump. The filter unit has a turbulence-producing device that produces turbulence in the water on the outside of the filter element. The turbulence in the water that is being drawn into the filter impedes or prevents the build-up of material deposits on the outside surface of the filter element.