I purchased the little rabbit/gerbil water container at the pet store and put it in either the crate or x-pen if I'm leaving the house for any length of time and won't be able to take them out to potty. They can get a drink from it in the amount that they want to keep licking it to activate the water release....but you don't have to put a bowl of water down so it gives them fresh water with out a huge supply. (Plus since I have several - they would dump it playing) That is only if I'm going to be away. They learn very quickly how to lick the small spout for the water to come out. Just be sure and watch it and keep it refilled for them.
Just a thought - I also use it in the small crate when we got on trips so they always have water - the little plastic trays to snap on the wire always seem to spill
Hope that helps.
</IMG>