if you have a water purifier, go for it! if not, you and your buddy may want to split the cost for a good one. make sure it's a -purifier- and not just a filter. the news about the army dumping "treated" VX nerve agent byproducts into the delaware river was a huge wake up for me. the amount of other chemicals like sodium fluoride, pesticides, and countless pathogens can also be harmful to your health.
that aside, i drink close to a gallon of water every day with no adverse side-effects. i pee a lot, that's about it