Not sure about tap water, but my sister got really sick after accidentally swallowing sea water at the beach. I swallowed some, too, but I didn't become sick.
If you are not sure about the quality of water in the hotel, drink fresh juices (with no ice cubes), bottled water, or alcoholic drinks. Hot beverages using boiled water should be okay.
White sand on the beach outside the hotel I stayed in looked great. And it was a clothing-optional beach, too! For the entire week I was there, the weather was sunny, hot, and humid, but sweating while on guided excursions really felt great.