The wife and I do a fair amount of backpacking (PA, NY, ME, MT) and have used http://www.aquamira.com/consumer/aqu...reatment-drops
for years. Available at EMS and REI...
We've never gotten sick from bad water and the taste is actually not bad...very slight chloring taste...not as bad as some tap water I've had. That being said, we've always been in the mountains and had some sort of availability to mountain streams or small brooks where you could get clear water.
If I were headed into a situation where I didn't know what the water sources were going to be like, I'd buy a filtration device...we have an old Katadyn model that was really cool since the end spout fit perfectly into the top of a Nalgene bottle. It was super slow, but you could filter water from a puddle in the middle of the cow pasture and probably not get sick....not that I'd try, but I read it on the internet...must be true!