Nice to know there are people still drinking water. I have needed to recondition myself to tap water. Imagine, I got so spoiled with drinking bottled water I started to lose my taste for tap water. Now I drink from the tap regularly (yes... Even at Ft Hood, TX). I am one of those guys that will stop and tackle a sprinkler in a front yard for water. Filtering wild, water is not a big issue now days with all the compact filtering devices out there. Let's not forget the old school ways of improvising CLOROX and 2% IODINE tincture. Here is the basic formula used by most of the military guys all over the world.
1st: Select as clean as a source as possible and filter through something. (Coffee filter, sock, T-shirt...) This will get floaties out of the water and make your chem treatment more effective.
2nd: For a liter of clear water add 5 drops of regular CLOROX (the EPA suggests 8 drops per gallon). In the military we found that 5 drops per liter was about the maximum amount of Clorox you can stand without any side effects giving you a three drop extra "kill the bugs" effect. Note: 5 drops per liter smells and tastes like about 36 PPM but could be as high as 90 PPM (Water Buffalo or Lister Bag water).
3rd: Wait for the chemicals to take effect. The colder the environment, the longer it takes. Twenty min or so...
If you are going to use 2% Tenture of Iodine then use two drops per liter.
Also remember that direct sunlight can treat water. Supposedly you can take clear plastic bottles of water and leave them in the direct sunlight for a few hours and kill pertinent bugs from its ultraviolet light.
OK... That's the old school way, meaning 60s and 70s. Wish I had a line on a US Army 68 Siera. Then I could find out how out of line I am...