I have one of those big ice cream containers and i just put water in them. When they are dirty or ran out, i water the garden with the remains and just use my hose to put in some water. :)
I switched to auto chick waters.I like this sys. a lot better. ck them out at www.pamperedpulletsfarm.com can be hooked up both pressure or gravity. price is also good. nice people to deal with.