Pressure washing involves hooking a machine up to your garden hose and then allowing pressurized water and cleaning solution to travel through the pressure washer and clean various surfaces. Cleaning with a pressure washer eliminates the need to scrub or to use heavy chemicals unless you need more cleaning power. Pressure washing is especially helpful when you need to clean house siding, decks and patios.
Vinegar and Water
A solution of 3 -parts white vinegar and 7-parts water is less harsh than other solutions, and will help kill mold and mildew when pressure washing. The vinegar and water are not dangerous to plants, so you would not need to cover or protect them from the spray. Although this solution works well against mold and mildew, it is not effective against dirt and grime.
Bleach and water in your pressure washer are very effective against mold and mildew, but as with the vinegar mixture the bleach does not clean well. Bleach solutions are most effective if you are preparing to prime or paint. When cleaning with bleach, you should cover your plants or wet them down so the bleach does not burn the plants.
Soap mixtures help remove dirt and grime; some even degrease oily stains. Adding bleach to the blend ensures that you will also kill mold and mildew while you clean. A good general mixture is 1/3 cup powdered phosphate-free laundry detergent, 2/3 cup powdered household cleanser, 1 qt. liquid bleach and 1 gallon water. Remember that a pressure washer will dilute your cleaning solution, so if you require a stronger solution you should decrease the amount of water in the solution.
Some communities restrict what chemicals and soaps you can use when pressure washing. Check with your local university extension service to see if this is the case in your area. If pressure washing is restricted in your area, the extension service may be able to recommend solutions that meet your community's guidelines. Pressure washing without any detergents is still very effective; the pressure of the water alone is enough to clean most surfaces.