The answer to 'pressure washer mildew' is that pressure washers can be an effective tool for removing mildew, but they must be used properly to avoid causing damage. Mildew is a type of fungus that can grow on outdoor surfaces like siding, decks, and patios, and a pressure washer's high-powered spray can help dislodge and wash away the mildew growth.
However, using a pressure washer incorrectly can damage the surface, so it's important to start with the lowest pressure setting and hold the wand at least 6 inches away from the surface. You may also need to use a mildew-killing solution before pressure washing to fully remove the growth. If you're not comfortable using a pressure washer or the mildew is widespread, it's best to call a professional cleaning service to ensure the job is done safely and effectively.