Every pressure washer system, whether it is feeding by tap water, water tank, stream or pond should have a quality water filter installed on the inlet side of the pump. By nature, water is a carrier of minerals, iron, dirt, rust, and other contaminants. The impurity will get into the pump and cause the unloader and nozzle clogged, and cause wear.  Stops grit, particles or debris from entering pump and causing costly blockages or pump wear.  400 micron stainless steel mesh, will fit 1/2" or 3/4" hoses.