The answer to 'why is my pressure washer filthy' is that a dirty pressure washer is usually caused by a buildup of debris, minerals, or chemical residue. Over time, the pump, hoses, and nozzle can become clogged with dirt, grime, and other contaminants from the water source or the cleaning solutions used.
Some common symptoms of a dirty pressure washer include reduced water pressure, irregular spray patterns, and poor cleaning performance. To fix this, you'll need to thoroughly clean and maintain your pressure washer on a regular basis. This may involve flushing the system, cleaning the nozzle, and replacing any worn or damaged parts.