Article courtesy of the Rocky Mountain Bushcraft team: Jason Schwartz is an axe-wielding, modern day mountain man. He's also a Red Cross certified Wilderness First Aid Instructor, music aficionado, and known to some of the locals as the "Bear Grylls" of his area. Leah Klocko oversees the country music landscape of Pittsburgh as a radio personality when she's not editing articles about testing a new bushcraft knife or surviving in the wilderness.I originally learned this trick a few years ago while going through Red Cross training, but it's a technique that's still not widely known. If you have a clear PET plastic bottle and fill it with germ and virus filled water and leave it out in the sun for at least 8 hours in hot weather (up to 48 hours in cold weather), the sun's UV radiation will render it safe to drink. This process is known as Solar Water Disinfection. It's a great survival skill to know if you are close to a source of water of questionable quality and have run out of potable water. As always, be extra cautious and when in doubt, leave the water bottle in the sun for several hours longer than recommended if possible.