When you go hiking it’s important to bring water with you and to drink it liberally. It is suggested that you drink a quart of water before hiking and then drink 1 quart after every two hours. You’ll feel better if you stay hydrated, particularly if it’s very hot or very cold, the water will help you digest snacks or meals, and eliminate waste. If you go for an all day hike, it’s often good to carry a water filter or Chlorine Dioxide tablets so you can purify water from a lake or stream when you run out. One quart of water weighs 2 pounds. That's why so many people don't bring enough water on hikes. But, you need at least 3 quarts per day. If you know there is a potable water source on your route, you can plan a refill there. Or, take along a lightweight water filter to collect water from a lake or stream.