How to Make a Solar Still


Introduction: How to Make a Solar Still

We all know that getting clean water is one of our first priorities. When you find yourself in the middle of an apocalyipse or outbreak, that will be hard. That's why I decided to show you how to do it.

CAUTION: This only works on hot days.

Step 1: What You'll Need

You will need:

- A plastic sheet

- Something similar to a cofee can

- a stone.

Next, find a spot, where you will dig a hole.

Step 2: The Still

When you find a spot, you can start digging a hole. It should be the size of your plastic sheet.

Then, put your coffe can in the middle.

Cover the hole with the sheet and secure it in place.

Now all you have to do is put the stone on the sheet (in the middle) and you're done.

In a few days it should produce enough water for you.



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    The biggest problem is that at best you might get a cup of water a day from this, and you could easily sweat out several cups when digging the hole.

    Not so good for surviving

    4 replies

    May I suggest that the hole be dug at night, or early morning when it is cool?

    As I live in the desert, I now know when not to work!

    I am going to try this when I go to California City next week and see if it works

    last summer i made this and one day i got 2 liters per day and ussualy i get about 1 liter or more so you can easily survive with couple of these.

    How big was your plastic sheet, how much vegetation material did you put in the hole? Like I said, using a 4 foot by 4 foot sheet of clear plastic and filling the hole mostly full of fresh cut grass, I was only able to get about a cup in the Texas Summer with temp around 100 Degrees F.

    I was using about 1meter on 1meter sheet of clear polietilene. I dug a hole about half meter deep and just put 2liters bowl in the bottom to collect water. Water is coming from earth not any grass or what.

    Does not have to be a hot day. As long as the sun is out it will still work. I used to teach the technique to pilots, as part of winter survival even. I have built these and demonstrated their working in climates barely above freezing where snow wasn't available. As long as the ground does not have a deep permafrost, this works enough to produce high enough quantities of water to survive on. Can also be used as a desalinator in areas like the northwest where temperatures are barely above freezing. Have used these on the beaches of Washington as with daytime temps only few degrees above freezing and these still work. The condensation affect only requires the ambient temperature to be above freezing, not hot. Obviously the higher the ambient temperature the faster the still will work. That's why it's good to create more than one in adverse weather conditions.

    The same system will also work in sub freezing temperatures by lining your hole with reflective materials like a mylar sheet. Does require a wider and more shallow hole to allow for the most solar radiation collection by creating a parabolic effect.

    Over 30 years of survival experience, including teaching survial while in the Air Force.

    1 reply

    Also need to point out that solar stills do NOT remove all bacteria and possible harmful chemicals in the water. If this is your source for long term survival, the water is still going to need to be treared by boiling at a minimum. Obviously there's not much to do about chemicals without some type of carbon filter. So if that is a possibility you should also create a gravity filter using carbon.

    The science is simple. Use clear plastic. The way it works is that there is more moisture a couple of feet underground than at the surface (hence the hole). You should actually start digging, and keep going until the ground at the bottom of the hole gets cool and a bit moist. Even in the desert, you go down a few feet and you can feel a bit of moisture in the ground. Put a container in the bottom of the hole. Get a bunch of leaves, branches, and roots (inedible material). Crushh all the plant matter and place it in the hole around the container for a kick start. Cover the hole with clear plastic. The clear plastic magnifies the suns heat and starts sucking the moisture from the ground. Place a small stone in the middle of the plastic sheet right over the container. That moisture condenses on the plastic sheet, and it runs down into the container. As the ground around your still begins to lose moisture, the water in the ground wicks into the area that has dried out, and that is how you keep getting water from the same spot. Hope this helps. I have built them tons of times in 20+ years of hiking and climbing in the deserts.

    Does the moisture come from the earth under the tarp? I don't know the science behind this and am just curious.

    2 replies

    Hey, it's a bit light on info, isn't it? :) I have made these several times.

    This is best done with dark plastic, but any will do if the weather is warm enough.

    As the first image illustrates, you should fill the hole with vegetation - it should be non-toxic as the condensation they produce won't be entirely pure. Softer vegetation should work best. In areas with lots of cactus, you can hack it up a bit to expose the watery flesh.

    The science is this: The hot air causes water from the vegetation to evaporate and rise. Much like in a pot of boiling water, when the 'steam' hits the tarp, it should condense and run down the tarp to the center where it will drip into the can.

    Best not disturb the tarp for as long as possible, as letting air escape will cool it down and set you back.

    A similar alternative is to tie a bag with a smallish stone in it around a densely-leaved branch. Water will pool in the bottom of the bag.

    i think it works better with clear plastic because sun heats earth and water from earth will evaporate

    I've always wanted to try this! Such a great way to get water!