Search for the Todd Gas Caddy... they used to make a Water Caddy model. It has since been discontinued, but you can safely use water in the Gas Caddy instead. Otherwise, contact http://www.tufftechbagsofca.com/ They have a vest used by gardners and fire departments..the vest fills with like 20 gallons of water, and you can wear it to wherever you want to water or spray. It's not on their site, but I know they make it.

