DIY Project: How to Make A Solar Water Distiller

Make your own distilled water from stream or lake water, salt water, or even brackish, dirty water, using these DIY Solar Water Distiller plans. With just a few basic building materials, a sheet of glass and some sunshine, you can purify your own water at no cost and with minimal effort.

Distilled water is not just for drinking, and it’s always worth keeping a few gallons of it on hand. Clean water free of chemicals and minerals has a number of valuable uses:

• Always refill the lead-acid batteries used for solar energy systems or automobiles with distilled water

• Water delicate plants like orchids with distilled water; minerals and additives like fluoride or chlorine that are present in most tap water can harm plants

• Distilled water mixed with antifreeze is recommended for car radiators, as it’s less corrosive

• Steam irons become clogged with mineral deposits unless you use distilled water

The principle of using the sun’s heat to separate water from dissolved minerals has been understood for millennia, salt ponds being the best example of how this knowledge has been put to use in the past. In salt ponds, seawater is drained into shallow ponds and then baked and purified in the sun until all that remains are crystals of salt. In this case, the pure water that gradually evaporated away was considered a useless byproduct, but as far back as the time of the ancient Greeks it was known that seawater could be made fresh and drinkable by this process.

A solar still works like a salt evaporation pond, except that the water that invisibly evaporates is extracted from the air; the minerals and other impurities are left behind and discarded. As the hot, moisture-laden air rises up to the slanting sheet of relatively cool glass sealed to the box, water condenses out in the form of small droplets that cling to the glass. As these droplets get heavier, they roll down the glass to the collector tube at the bottom and then out to the jug.

Are you ready to turn back the clocks to the 1800’s for up to three years? Our grandfathers and great-grandfathers were the last generation to practice the basic things that we call survival skills now… WATCH THIS VIDEO and you will find many interesting things!  Click on the image bellow and learn more about Survival things that we lost to history.


At the heart of this design is an innovative method for forming a medium size parabolic mirror using a flexible aluminized mylar sheet (the shiny metallic foil commonly used to make potato chip bags/decorative balloons). I built an aluminum frame, using 1 inch wide by 1/8 inch thick strips, that runs around the edge of the mirror and use a pair of wires at either end to draw the frame up into a parabola. The mirror is actually sandwiched between an upper frame and a lower frame. This mylar sheet, frame and wire construction makes a good parabola, is inexpensive, lightweight, and can be easily assembled/disassembled.

The aluminum frame is much stronger than necessary (& more expensive) and could easily be made out of a cheap local material like wood or plastic. The function of the frame is to 1) hold/capture the mylar sheet, and 2) provide some stiffness so the wire stays taught. The wire length determines how steep or shallow the parabola is, which in turn determines how close/far the focus of the mirror is from the mirror surface. The mirror is cheap (a few dollars) and ideally the frame should only cost a few more, altogether I’d guess it should cost under $10 to make the mirrors in any serious volume (maybe $10-$15 in moderate volume). I say should, because I’m still working with a prototype, and a custom job costs at least 10 times what I think the cost should be… Still I imagine a big cheap mirror can be useful in any number of solar applications besides water purification.

The mirror is placed under an evaporation chamber where the water is purified. The evaporation chamber has an aluminum pan (painted black to absorb the sunlight/heat) into which I add a trickle of ‘dirty’ water which is heated until it evaporates. This pan has a clear plastic cover which captures and condenses the water vapor as well as an interior lip that channels this pure/condensed water out of the distiller. The two piece evaporation chamber can be taken apart for cleaning or storage. At the moment the parabolic mirror needs to be adjusted by hand each hour to keep the sunlight focused on the pan, although this ‘tracking’ could be automated fairly simply by adding a small motor.

In the interest of keeping the device portable, I’ve only used a 2 square meter mirror which distills ~ 1 gallon of water/day. I’m working to boost the treated volume by a factor of two with additional design improvements—in theory a mirror this size could distill 4 gallons/day. I could also increase the distilled water production volume by using a larger mirror, doubling the mirror would double the production, although it would be that much harder to transport. The device weighs about 40 lbs, and the mirror can be rolled up like a poster.

In fact my big problem at this time is that I’m collecting too much sunlight/heat onto the pan and the plastic cover gets so hot (60-70 degrees C) that the water vapor doesn’t condense as well as it should. The little metal fins at the top of the distiller are designed to help remove heat from the condensing cover. For scale, the mirror is 6 ft. x 4 ft. and the evaporation chamber is roughly 3 feet off the ground.

This is a fairly simple device. I’ve spent a few years working and improving the design almost entirely on my own. Last year I filed for a US patent on it, so the design is officially patent pending. I’d be delighted if some person or group found a situation in a developing/island country where this distiller would be useful (and I’d be happy to help in any way I can—adapting the design for local construction with local materials etc.), but I don’t want some major US corporation copying the idea, filing for a patent and potentially preventing me from using my invention!

Watch this free survival video and Learn How to Make the Ultimate Survival Food: Pemmican was light, compact, high in protein, carbohydrates, vitamins, and if done properly can last anywhere from a few years (decades) up to a lifetime without refrigeration!