J.,
There isn't necessarily any "normal" when it comes to the human body - only a range of normal. The best check is as another posted said, to check her urine. When we are properly hydrated, our urine should be nearly colorless and odorless. If your daughter has dark and/or smelly urine, then she is not drinking enough. If she is dehydrated, you can't make her "go" more. She needs to drink more, otherwise she has nothing to pee.
My girls like having their own sipper cups, which I keep filled with water and they can cary around with them. I also remind them to drink several times a day. Just like me, they forget to take a drink, and once someone reminds them, they realize they are ravenously thirsty and chug half the bottle! You could offer watered down juice if your little one won't drink water, but be cautious how much juice she is drinking. Even natural juices have a lot of sugar in them. My girls will drink water, but they really like it when I add a little tea or a squeeze of lemon. Just a little is enough to do the trick and add a little flavor without a lot of sugar. Tea has beneficial properties also. We have been drinking green tea sweetened with honey, and watering it down by half. I only give it to them at mealtimes, and they think it's a special treat!
Best of luck with your little one,
S.