I felt totally bad, cuz the first few days I had Molly, I kept her water in one of those little bottles that hang on the side of the cage. Well a few days later there is hardly any missing, and when I thought about it, I never saw nor heard her drinking from it. So I buy a little ceramic dish and fill it with water, and she drinks until the bowl is completely dry! Then I fill it again and she finishes off the water again!!! Then I do it again and she drinks it halfway gone….poor thing…her bottle must not have worked properly cuz she was dehydrated! I mean she still got water from her veggies, but not enough obviously. That was several months ago.
Then I recently bought her a new cage, and it came with its own bottle. I tried to see if she would drink out of that, but it still seemed like it wasn’t working. Maybe she just couldn’t do it?? Or maybe I could two faulty bottles in a row? Now I don’t even bother with a bottle. Its all ceramic dishes for her now! 
I guess this is how raising kids will be like. You end up learning the hard way what to do and what not to do. You can read all day long about proper care and such, but you don’t really know anything until you have the hands on experience of being a mom/dad. Thankfully she is fine and gets all the water she needs now. 
Any others out there like me and learned the hard way??