Definitely water filter! Definitely not bottled water (unless you also filter it). Even in Norway, where you can safely drink water straight from the tap and where food industries are quite tightly controlled, tests of bottled water show that it has more bacteria than tap water or water from fast running streams. In poorer countries I would imagine that many would be tempted to simply fill up bottles from a stream or faucet somewhere and sell them. After all, people have got to make a living! But I'd rather buy (peelable) fruit from them and filter my own water, or buy their water and filter it before drinking. We did that in China. Filled up some Nalgene bottles every morning and drank our own; carried along the little filter pump in case we needed refills.