Power washing your house can be bad for it if not done properly. If the water pressure is too high, it can damage the paint or siding on your house. It's important to use a lower water pressure and adjust the nozzle on the hose to get the best results. Also, make sure to avoid spraying any water towards the windows as it can cause them to streak.
There's no one definitive answer to this question. It depends on a variety of factors, such as the composition of your house's exterior paint or siding, and how long it's been since it was last power washed. In general, though, power washing can be a great way to clean off years of built-up dirt, dust, and grime from your house's exterior. But you'll want to take care not to damage the paint or siding in the process. So it's always best to consult with a professional before power washing your house. They'll be able to give you specific instructions on how to safely power wash your home without damaging it.
