This is the best invention for anyone with a dog. We have a lab and where we live it is always, always hot, so we were filling her water bowl up multiple times a day it seemed. Buying this has ensured that our dog always has water when she needs it. It holds about four gallons and it stops itself from releasing anymore water when the bowl is full. It also filters the water before it goes into the bowl, which is great because our tap water isn't the best where I live. I would honestly recommend this to anyone with a dog. We got ours from Amazon, I believe, but I know you can also get them from petsmart.