Here is my attempt at a spot free rinse. Menards had a sale and marked rain barrels down 20%. I plumbed into our current one and built the stand to be 1/2" higher so it would not overflow. I have an overflow on the first one plumbed into the gutter. The rain is collected into the fist barrel and the dirt and grit will hopefully fall to the bottom of the first barrel before entering the second barrel. I will purchase a pump-up garden sprayer and put a filter in the hose to trap any grit that may be in the water. Any critiques before I rinse my car? Note: the height difference causes the water about an inch below the surface to flow into the second barrel so it doesn't get the crap floating on the top.