Whilst on the subject of water, I should point out a few extra things. Firstly, you should not take ice in your drinks. Freezing won't kill all the bugs in water. Never have ice. Get used to it.
Warm beer is better than the alternatives.
Boiling is a great way of sterilising water. If you have to drink unclean water, try to minimise the amount you drink. In general, with a bit of care and some planning, there is no reason why you should drink untreated water. They are usually made in local factories with purification plants built in. Coke, of course, is just everywhere on the planet.