Always filter your water
Recently the U.S. Environmental Protection Agency reported that 90% of the world’s fresh water is contaminated. While Giardia is often considered the primary water safety concern, wilderness studies suggest that many back country illnesses are actually caused by bacteria or viruses. Don’t let bad drinking water ruin your trip. Always use a drinking water system to protect your health.
You can use many different water filters. There are filters by Katadyn and MSR that work well. One thing to consider is prefiltering. You can use a coffee filter, bandana, or in a pinch, a sock. If you have the time you can also fill a water bottle and let it set out for awhile to let the sediment settle and filter from the top. Silty water will clog a filter very easily and make filtering a serious chore.