To limit our trips to the river and still have plenty of clean water to rehydrate meals and quench our thirst, we pack along MSR's Autoflow XL10L Gravity Filter. We simply hang this high-capacity filtration system off a tree by camp and fill our pots and bottles as needed throughout the day. And with a 1500-liter lifespan, the cartridge continues to give us clean water again and again all season long.