The stories are often stretched. In the field a human needs roughly 2 liters a day if you’re active and in heat. If you’re resting, a bit less – maybe 1.5 liters – but you’re still talking a few hundred milliliters a day at minimum. A bucket of rainwater can last a few days if you ration, sit in shade, keep moving slowly, and use any high‑calorie, low‑water foods you have. You can push it to three or four days in extreme conditions, but that’s a knife‑edge margin and you’ll feel awful. In practice, gather as much rain as you can, store it properly, and treat it like a precious resource. If the rain stops, you’re out of a window in about 24–48 hours unless you have a plan for a still or another water source.