Make your own Rain barrel. The important thing when collecting rain water would be to keep algae, mosquitoes , etc from growing in your storage container. If you have a rain barrel that catches water from the downspouts, I'd be concerned if you have asphalt shingles. I hear that toxins can leach out into the water. If you have concrete, tile, or metal roofing or are collecting the rainwater some other way then no problem.