Planning Water on a Hike: Sources, Carry Amounts and Refills
Running out of water turns a pleasant hike into a hard one, but carrying far more than you need is heavy and tiring. Planning water means knowing where you can refill, how hot it will be and how hard the route is.
Finding reliable sources
Mark streams, lakes and springs on your map, then check recent trip reports or ranger updates, since seasonal sources dry up in late summer. Treat any natural source as unreliable until confirmed.
Note the longest dry stretch on the route; that section decides how much you must carry.
Estimating how much to carry
Needs vary widely with heat, humidity, body size, pace and terrain, so learn from your own experience on shorter hikes. Many hikers plan around a set amount per hour and adjust upward for heat and steep climbs. Add extra for cooking and a reserve for delays.
Thirst is a late signal; drinking small amounts often works better than large amounts rarely.
Weigh the trade-off honestly: a liter of water weighs about a kilogram, but running short on a hot climb is far more costly than carrying an extra bottle.
Refilling well
Refill before you run low rather than waiting until a bottle is empty, and treat all natural water. Drink well at each source so you leave fully hydrated.
Carry a collapsible container for dry camps, where you need water for dinner, breakfast and the next morning's walk.