Be careful not to spray in areas that are open and get water inside the house. Also be careful not to spray windows if the pressure is very high. Never get on a ladder to reach high spots. It is much to dangerous to work with a pressure washer and try to balance on a ladder. Remember, this is extremely high pressure, so never point the nozzle at anyone and be sure to wear safety glasses. Of course, never spray water around electrical wires.
Protect any plants, light fixtures, or other breakable objects around the house with plastic bags, duct tape, and drop cloths. Move obstacles and outdoor furniture away from the house. A pressure washing unit is no toy. Be sure to wear safety glasses and do not underestimate the power of water. Professional and effective cleaning will extend their life expectancy considerably,