Depending on the temperature outside, you can last only about four days without water. To ward off dehydration, search for animals, birds (especially songbirds), insects (especially honeybees), and green vegetation, all of which can indicate that water is nearby. Rock crevices may also hold small caches of rainwater. As a last resort, try digging in dry creek beds or muddy or damp ground which may reveal hidden sources of ground water. Keep in mind that any untreated water could be contaminated. Keep an eye out for these signs of dehydration so that you know you need to find water fast.