3 Best Pressure Washer Detergents to Help Banish Mildew and Grease

Preparing the soaps for use is the same for all the products we tested: Follow the manufacturer’s instructions to dilute with water (they’ll provide the ratio). Then spray on a quantity of the detergent at low or no pressure, allow the solution to soak in, then rinse at high pressure. At least one formula can be used without dilution.

You may not need a pressure washer at all. Especially when fighting mildew, just using a little pressure washer cleaning solution by spritzing on the solution with a simple spray bottle—then applying elbow grease and rinsing with a garden hose—yielded great results. 

In some cases, pressure washing alone did the trick. During testing, especially on mildewed concrete walks and metal roofing, high-pressure water with zero soap proved nearly as effective, but slower. If you already have a pressure washer, try cleaning the surface with plain water first. The suds definitely killed mildew faster, and this was especially true on both metal and concrete walks. 

Caution: Two of these products list eye irritation as a warning, and two warn that they can cause irreversible blindness. So wear protection, not just glasses, but safety goggles, that will prevent overspray from getting into your peepers. Also, wear gauntlet-style rubber gloves and heavy boots, because all of these products can cause skin irritation, and it’s difficult, if not impossible, to prevent spray from hitting your hands, feet, and arms.