Water in the crate?

For those of you who crate your dogs when they're home alone...do you leave water in the crate?

Biscuit is about 13 months old and does fine in her crate. We're out of the house from around 9-5:30 every day, but we have a dog walker who comes around 11:45 and takes her out for a half hour. After that walk, the dog walker leaves her with a Kong we fill the night before with plain nonfat yogurt, unsweetened applesauce, and a few liver treats (or something similar) and freeze. We're careful not to put anything too salty in the Kong.

When we're home, Bisc is out of the crate and has free access to water until around 10pm, later if she seems thirsty or we're going to be up late. She tends to play with her water and drink for fun, which is fine. She doesn't seem outrageously thirsty when we get home or anything.

I'm wondering if I can leave well enough alone, or if we should put a bowl in the crate or something. I bought one of those hamster bottles that attaches to the side of the crate, but Biscuit seemed scared of it when I tried to show her how it works. Is a 6 hour stretch without water (but with watery Kong treats) too much?

Thanks for indulging my doggy paranoia!