Solar Still for Camping
Whether you’re just trying to impress your buddies at the campsite or you’re actually dying of thirst, building a solar still is an impressive wilderness survival skill. A solar pit still is a technique for creating fresh, drinking water that goes back hundreds, if not thousands of years.
Here’s the underlying principle of a solar pit still. Basically, there’s water in the air that you breathe and there’s water in the physical biomatter around you – the plants. If you trap the air and those plants and heat up the space, then the water inside gets heavy and evaporates.
The great thing about a solar pit still is that it isn’t difficult to create if you have the right tools on hand. If you’re going on a planned camping trip, then you’ll probably have everything that you need in your kit already.
It’s not hard, even for novice outdoorsmen. I promise, you don’t need to be a big-time lumbersexual to figure this out. You basically dig a hole in the ground, wait a few hours and come back to a pool of fresh water. Well, it’s not that simple, but you can make it look easy after reading this brief guide.
Here’s what you’ll need:
(*) A plastic bag, preferably a large, black plastic trash bag.
Note: You don’t want to leave plastic bags around while you’re camping, but a black trash bag could be very useful. Just remember to keep it with you and don’t leave it behind.
(*) A handful of thick, fleshy leaves, chunks of cactus, or water-logged vegetation
Note: You can sometimes tell which plants have lots of water by giving them a squeeze. It should be thick and squishy to the touch.
(*) A digging or cutting tool
Note: If you didn’t bring any tools for your outdoor adventure, then shame on you. Luckily, you can use your hands to dig the solar pit still.
(*) A water collector such as a tin pan or anything that can hold water.
(*) A small pebble, rock, or coin
The Basic Steps to Creating a Solar Pit Still
First, harvest some thick leaves, water-logged logs or pieces of cactus from your site. You’re looking for fleshy leaves and vines that have water in them. You can give them a squeeze and if they feel a bit spongy then you’ve got the right ones.
Then, dig a small hole. It doesn’t have to have a wider circumference than about a meter because the black trash bag must cover the hole completely. Keep this in mind while you’re digging. So you don't want to make the hole too wide. You can make it as deep as you want, to fill more air into the space.
The next step is to place the foliage inside the hole in a circular fashion and your water collector plate in the center. Cover the entire hole with the trash bag, mounding dirt on the outside rim. Try to make the space airtight by cleaning up the edges. Make it nice and tidy, fellas.
Then, place a small rock, pebble or even a penny on the center of the bag. It can’t be too heavy or too light. So, you might need to play around with weighted objects until you get a small dimple in the center of the plastic bag. This will create channels for the water to flow. The pebble should be directly over the center of your collection plate.
What Happens Next?
Well, now that you’re done constructing the solar still, you just wait it out. The air inside the pit heats up over time and droplets of water will begin to form on the inner surface of the plastic bag. This water will channel down toward the center where you placed the weighted pebble. The water will accumulate and drop straight down into the collection plate.
How much water will you have? Well, if you wait two to four hours then you’ll come back to the pit with a pleasant surprise. You'll have anywhere from 12 to 24 ozs of water waiting in your collection pan.
This isn't enough for an outdoor shower, but you can stay hydrated throughout the day. The water you collect is perfectly safe to drink. Now, if you’re with a group of campers, then I’d recommend digging several pit stills to accommodate the entire group. You can experiment with the set-up and do variations on this technique to make even more water. So, feel free to play around with different materials, deeper pits, and steeper angles.
If you want a quick visual reference for creating solar pit stills, then check out this Howcast video.