I totally agree with Nimrod... I always use boiling, filtering or iodine tablets and neutralizer. If I am going to be in a stationary camp for a few days I just get a 5 gallon bucket full of water as soon as I arrive..drop in the iodine tablets and while they work I set up camp. 5 gallons is more than enough water for two guys and cooking water. When I'm on the move I carry a small pump filter.

I got a case of giardia from a high mountain stream. It was the only non filtered or city water I had drank in a month so that had to be it.