Edit 6 years later: wow - I handed out advice with undue confidence back then. Ignore this post and do whatever you find works for you.
Stay hydrated people! - For POTS type stuff it's particularly important, but most people should try to drink more than they naturally feel they want. We're lucky enough to have access to all this good, clean water, so lets make the most of it!
I definitely don't have enough of a natural desire for water. My partner has been pushing me to drink more for years though, so I'm a bit more in the habit now. GL all.