You require a steady supply of water to sustain yourself in a survival situation and without it you will dehydrate. Left unchecked, dehydration will end in death. To survive, a balance between water intake and loss must exist. 

Why you need water
Water is needed, directly or indirectly, for every physical and chemical process occuring in your body. Here are a few functions that water performs:

• water carries oxygen, nutrients, and other essentials around the body. 
• the kidneys use water to flush out toxins and waste matter via urine. 
• water regulates your body temperature. 
• the lungs use water to moisten inhaled air so that it doesn’t irritate the sensitive pulmonary linings. 
• water helps conduct nervous impulses around the body. 
• water protects the vital organs and provides lubrication around the joints.

WHAT IS DEHYDRATION?

Dehydration occurs when you fail to replace the water your body loses. Possible factors include high and low temperatures, humidity, work rate, clothing, body size, fitness levels, and injury.

NATURAL WATER SOURCES

If rainwater is not available, there may be other natural sources of water, from visible streams to hidden bores and holes. Whatever your source, you should always treat the water before drinking it.

SPRINGS
These occur when water is forced to the surface due to subterranean pressures or gravitational flow from higher sources. They provide a permanent water source in low-lying areas. Contrasting green vegetation indicates their presence.

STREAMS AND RIVERS
The closer to the mountaintop the river or stream is, the clearer the fast-running water will be. Either check upstream for contaminants, or follow the water downstream. Collect the fast-flowing water near to the surface.

ROCK HOLES
Usually found in high ground, rock holes are natural collectors of rainwater.

WELLS AND BORES
Wells, which may be featured on local maps, can be deep and covered. In remote areas, wells are covered and marked in certain ways by the locals—find out what the markers are for your area.

LAKES AND PONDS
Rivers, streams, and water run-offs all flow into lakes or ponds. Collect water as it runs into the water body, as static water becomes increasingly stagnant.

SEEPAGE
Usually located at the base of cliffs or rocky outcrops, seepage is caused by slow-running channels that drain off these features.

SOAKS
Soaks are found close to rivers and creeks in low-lying areas, and are normally lower than the existing water table. Their presence is often indicated by vegetation and they may be subject to pollution due to their use by animals.

AVOIDING POTENTIAL DANGERS

Most water sources are likely to be used by animals for drinking, bathing, urinating, and defecating, so always filter and purify any water collected before use, the only exception to this rule is rainwater. When collecting water, you should also be aware of certain dangers. You may encounter dangerous animals either using the water source, or on the way either to or from it. Most major water sources have a ranking system to determine which animals can use it. If all of the small gazelles suddenly disappear, ask yourself why. If you’re collecting water from rivers, consider the potential dangers of river wildlife. If using dry riverbeds during the rainy season, be aware that flash floods can move quicker than you can run.