It's actually the same type of dye used in the injection systems in tub grinders. It's not a paint at all. It's completely water soluable, but it's best to rinse it off of siding or walks before it dries just to be safe. We charge a min. per square foot rate.Commercial clients love it, and considering a new mulch install with no weed control can run over $ .85 per square foot, it's an easy sell to high visibility clientele.