How much water should I bring on a hike?

The general rule is half a liter (about 17 oz) per hour of moderate hiking in mild weather. In hot summer conditions, plan for 1 liter per hour. For a 3 hour summer hike, bring at least 2 3 liters. A 32 oz insulated bottle covers most 1 2 hour hikes. For longer hikes, bring two bottles or use a hydration bladder. Always bring more than you think you will need dehydration sets in before you feel thirsty.