I sit mine across the door jamb in the pen, it's a 2 x 4 basically. Plenty of room to balance the 3 gallon water pail, with the bottom / vertical nipples, spray it out, wipe it, whatever I need to do and fill it back up, with the valves not being depressed at all. It balances pretty well too so you can fill it w/o having to worry about tipping over.
WHen I do clean it out, Ill dump it a few times to make sure any grungies that might have wanted to start to grow in there, and slimies on the walls are gone, and I'll also reach under and press each valve several times to make sure anything up in them is cleaned out and they are operating properly too. I'll fill it, put the lid back on, and leave it set on the 2 x 4 cross beam so I can watch it for a minute or so, to make sure none of the nipples are leaking, and if there are problems, take care of them before I pull the thing back up into the ceiling area and out of the way.
Edit: I have my water bucket hanging up over their heads, taller than their butt feathers so they don't stand under it, depress and valves with their tails and drain all the water out.. (ask how I know about this ! )

when they want a drink they just basically reach up, wiggle a valve and let the water go down their throats.
Aaron