My two thoughts are:
(1) use star san to sanitize, and store in a keg. As long as you keep it clean and out of the light, a star san solution lasts a very longtime;
(2) get a plate chiller.
You can probably save a little water in the cleaning process by using just a little PBW or OxyClean solution, and a lot of elbow grease, as opposed to just soaking like I do.