We need the ability to boil water. Be it using a cooking pot, a skillet or an empty tin can. Given with how persistence will work water purification tabs might not always be available and we need an authentic viable solution. I would also make mention that it should have to cool before drinking it or it will burn you. This takes out having the wear and tear model for canteens and water bottles. You might possibly add a loss chance for plastic bottles given the mouths are much smaller than the canteen.