Hi,

I work for the Forest Service in a large wilderness area so I've spent some time in the high country with only my filter to rely on.

I've had Giardia twice in my life. This was from drinking water without using a filter. I have never drank water since without using a filter. Trust me, if you get sick with Giardia while in the back country (incubation is ~two weeks if i recall) and your alone...you stand a good chance of not making it out.

It was the worst illness by far I have ever seen or heard of. You are in a constant state of dehydration and weakness, I also had chills, fevers, sweats and persisent diarrhea for more than 24 hours before I finally sought medical attention. Basically, you will be incapacitated if you get this disease.

I strongly reccomend NOT drinking ANY water no matter how clean it looks without first filtering it. There are a ton of easy to use, light, and relatively inexspensive water filters on the market.

I personally use one from www.MSRcorp.com which is Mountain Safety Research. I will provide you with a link to what I feel is the best model they have to offer.

http://www.msrcorp.com/filters/simplicity.asp

good luck!