Kristykins,
I'd recommend that you drink bottled water, if you're drinking beer, rum or nothing else. The tap water is Ok for brushing your teeth and whatnot, but it's not very plesant. Get a big jug of bottled water and kep it in your room. Stay hydrated and you'll enjoy your vacation more.
I spend a lot of in the desert and a lot of time in the tropics. I can tell you from my own experience that becoming dehydrated is not plesant. Often, the first symptom is a hangover-like headache that refuses to go away. Once you're dehydrated, the headache stays with you even if you drink gallons of water. And, if you're drinking alcohol, soft drinks or coffee the onset of dehydration sneaks up on you. The effects of dehydration are worth avoiding, so drink lots of water.
Dan