When it comes to water pressure, more isn't necessarily better; in fact, if your water pressure is too high when you're pressure & power washing, it's possible to damage delicate surfaces like wood and roofing. Ask for the company's default water pressure setting, which is measured in pounds per inch or gallons per minute.
While some companies may use plain water to power wash your driveway, patio, or roof, other companies may throw certain chemicals into the mix that help with the cleaning process. If you want to protect your health and the health of your family, however, you should make sure that the company you're interested in only uses eco-friendly and non-toxic cleaning products.
The right pressure & power washing company will be fully licensed in your state, and they will also be properly bonded. Additionally, if a company seems to be unwilling to give out estimates or references, it might be time to try a competitor. Lastly, if a power washing company's rates exceed $0.80 per square foot, look elsewhere.
While a little bit of water might seem innocuous, when this substance is under pressure, it can cause serious damage to a home. High-pressure water can even hurt you, so it's best to leave to pressure & power washing to the professionals nearby.