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Finding Water in the Wild
You’re in the middle of a multi-day hike. The plan was to follow the trail, but you took a wrong turn. Now you’re lost. You try to get back to the trail unsuccessfully and end up spending the night in the backcountry. By the time you wake up in the morning, you’ve finished your water and are thirsty.
How long can you last without water?
The Rule of Threes suggests that the average adult can survive about three days without water. But tell that to the handful of hikers who die of dehydration each year during a day hike. The Rule of Threes isn’t a hard and fast rule, but rather a rule of thumb.
In short: water is one of your top priorities in wilderness survival because you can’t last very long without it. You probably already knew that. Knowing you need water is the easy part. The hard part is actually finding the water.
Here are some water sources to consider:
1. Lakes, Ponds, Rivers, Streams
The most obvious place to get water from is a lake, pond, river, or stream. These are the bodies of water that you would see on a map if you have one (and you should).
In order to decrease the likelihood of contamination, you should prefer fast-flowing water at higher elevations and away from human habitation and livestock.
Avoid water if you see an oil slick on the surface. Filtering and boiling do not remove chemicals. Be wary if there’s no green vegetation growing around the water or if there are animal bones present, which are signs of pollution. Also be careful if there are a lot of mineral deposits along the edge of the water, which could indicate an alkaline condition.
2. Puddles
If there aren’t near any obvious water sources, look for natural water catches — puddles. You can often find puddles of water on big rocks, in the crook of a tree, or in valleys. Look especially in the shade.
On mountains, look for water trapped in crevices. Also look for lush vegetation on the faults which could indicate a spring.
Stagnant water in a puddle is prone to contamination. Check it for excessive algae or animals living it in. Don’t drink water caught in poisonous trees.
Once you’ve decided that a puddle is probably safe, collect water from it by soaking it up with a cloth and wringing it out into a container. Filter and boil before drinking.
3. Birds & Bees
Animals can indicate a nearby water source. Birds and mammals drink at dawn and dusk. Following them can lead you to water. You don’t necessarily need to see the animals. You can follow game trails downhill, which will often lead to water.
When birds are heading for water they fly low and straight. When returning, they fly from tree to tree, resting often. Focus on the grain-eating birds like pigeons. Birds of prey and water birds do not drink frequently, making them poor indicators of nearby water.
Meat-eating animals are also poor indicators because they get a lot of their moisture from prey.
Look out for insects too. Bees are a reliable sign that water is nearby. Bees typically stay within 4 miles of the hive, and the hive is always within 4 miles of water. Most flies stay within 100 yards of water. A column of ants walking up a tree is going to a trapped reservoir of water.
4. Rain
Rainwater is probably cleaner than anything you’ll find on the ground. You won’t catch much by leaving your bottle out in the rain or by looking up at the sky with your mouth wide open. Build your own catchment with a tarp or leaves, running the water into your containers.
You may need more containers to take full advantage of rainfall. You can fashion a makeshift container by hollowing out a wooden stump or by digging a hole in the ground and lining it with clay. You can even use a natural rock depression to store water.
5. Dig a Hole
If you dig a deep hole into wet dirt or sand, it will slowly fill up with water. Look in the same places you might find a puddle — valley bottoms, dry stream beds, etc. Under patches of green vegetation is also a good bet.
If you’re on the coast, dig above the high water line to avoid salt water.
6. Morning Dew
In the morning, when all the vegetation is covered in dew, you can collect it. Use a cloth to soak up all the moisture and wring it out into a container. If the vegetation is low to the ground, you can tie the cloth around your ankles while walking through it.
7. Distill Water
If you can’t find water, you can distill it from anything moist, like wet soil and plant cuttings. You can even distill clean drinking water from urine.
There are two easy ways to distill water in the wilderness. The first is to boil it in a pot using a cloth to cover the top. When the cloth gets saturated with clean water from the steam, wring it out into a container.
The second way is to build a solar still by digging a hole which will work as a hot box. Fill it with your most stuff, add a collection container in the center, and cover it with a plastic sheet (e.g. tarp, poncho). Put a rock in the center of the sheet so that any liquid that condenses under it will drip into your container.
Remember to leave the cup empty. Clean water will drip inside. The dirty water, vegetation, and piss go outside the cup. You don’t want to mess that part up.
Both these methods are time-consuming, but it’s good to know them in case you have no other options.
8. Plants
You can cut open some cacti, like the fishhook barrel or the prickly pear, and either eat the pulp or wring the water out of it. However, many others will make you sick.
Bamboo often traps clean drinking water.
Water can sometimes be harvested from tree roots near the surface by removing the bark and sucking out the moisture. Or you can shave it to a pulp and squeeze the water out.
Some palms trap water that can be drained by bending a flowering stalk downwards and cutting its tip. The water will be renewed every 12 hours.
Some vines also contain water. However, some are poisonous.
Unless you’re familiar with the plant and are sure it’s safe to drink from, it’s a better idea to extract the water from vegetation using a solar still.
9. Seawater
Don’t drink seawater directly — it’ll actually dehydrate you faster. The high level of salt draws water out of your cells, not the other way around.
You can, however, distill fresh water from salt water using one of the two methods above. When using a solar still, just dig the hole in the wet sand and that’s your still right there. The boiling method is self-explanatory.
10. Snow
In a cold climate, you can melt ice or snow to get water. Melting is preferred over eating it directly so that you avoid lowering your core temperature. Also prefer ice over snow, because you’ll get more water for the energy you use to melt it.
If you don’t have a fire to melt with, put the ice into your water bottle and place it under your jacket. Eventually, it will melt from your body heat.
If you need to melt sea ice for water, pick the older sea ice with low salt content. It’ll be blue with smooth edges.
Be Prepared
The surest way access water is to pack enough with you.
Carry more than you think you need — at least 2 liters a day per person. In the desert, carry at least a gallon per day per person. If you’re dependent on finding water on the trail, make sure you know where that water is and how reliable the source is.
It’s great to know all these potential sources of water. Keep the ideas in mind in case of an emergency. Practice finding water during regular hikes, when the stakes are low.
Know. Prepare. Survive.
Mike Lin is the owner of Rallt — a gear company and blog for backpacking light.