Look in Lowes or Home Depot. They will have a section near the power washers and it will have a selection of different washes. Boats, cars, homes, etc. Don't know how they are different.... I had some called "green" something or other and it said it wasn't harmful to flowers, shrubs, etc. It worked and didn't kill anything.
WARNING; if you've never used a power washer before be real careful around anything painted. Doors wood trim and the like. I lent my washer to my neighbor and even after I warned him, he had to do a LOT of repainting when he was done!
