Published on March 13th, 2009 | by Derek Markham


The Watercone: A Simple, Effective Solar Still

In many parts of the world, lack of access to clean, potable water is a major issue. Water may be found nearby, but only in a brackish or polluted state. Areas close to the ocean may see miles of water, but not a drop to drink. UNICEF estimates that every day 5000 children die as a result of diarrhea caused by drinking unsafe water. The Watercone could change all of that.


The Watercone, invented by Stephan Augustin, is a conical solar still made from recyclable polycarbonate, with a screw cap spout on the top and a collecting trough in the base which catches the condensation for use as drinking water. The design is ingenious. It’s simple, cheap, and effective. The units even nest together to reduce the transportation costs.


The Watercone concept is easily understood by almost anybody within seconds, and there’s no need for technical jargon or complex directions. There are no parts to replace or maintain, and the cone and base are made from Bayer Makrolon, an ultra-tough and recyclable UV resistant polycarbonate. The base is made from recycled polycarbonate.


Simply place the cone over a pan of salty water (or any damp ground, even floating on a pool of water), leave it in the sun to evaporate, you flip it over at the end of the day, take off the cap and drink or store the water.


The Watercone site claims that one cone can produce one liter of water per-day (on average). The life expectancy is 3 to 5 years, and even when the polycarbonate gets cloudy and reduces the effectiveness of the distiller, the cone can still be used to collect rainwater.

The solar estimate solar calculator shows how much solar panels cost per kw, solar system prices, solar rebates and incentives and the best rated solar companies in each county

Tags: , , , , ,

About the Author

29 Responses to The Watercone: A Simple, Effective Solar Still

  1. “Price: planned below € 20.- ” from the Watercone website. I find price suprisingly high. I would have though price in below 1 euro. After all it is just plastic cone.

  2. john mathews says:

    Hey, instead of having the completely stiff upper cone, do a flexible upper membrane with a stiff circular base . The center of the membrane can be pulled up and attached to a vertical bar to make the cone shape. Then, the whole thing can be stored as a flat circular disc.

    Also, think of putting a small tap on the bottom stiff circular base of the cone so the water need not be emptied out periodically.

  3. john mathews says:

    Taking the previous idea further, it might be better to make the bottom water container and the stiff base of cone (as i outlined in the previous comment), hexagonal for more efficient packing.

  4. deborah says:

    Very ingenious. I think the problem solving is very elegant.
    Question: Does this plastic, like #7 plastics, have hormonally active toxics? If so, especially when warm
    the plastic will leach contaminates into the water.

    I hope not, or this gift is not without the potential to create havoc on the users.

  5. Pingback: Watercone. Clean water from brackish water using solar energy |

  6. Claude says:

    how would someone be able to maximize the amount of fresh water created – it’s needed for cooking and cleaning, not just drinking, and 6-7 glasses like the one he held, created in 24 hours would not meet one persons needs let alone providing for a family. are there larger/more efficient versions for families? villages?

  7. az says:

    Great invention, but polycarbonate is a bad choice due to it seeping BPA into water it comes into contact with (especially at high temperatures). See this NIH report:


    Pyrex-like shatterproof glass would be a better choice, and probably last longer.

  8. Jack Handy says:

    Looks like the one I use to sell about 10 years ago. Should work very well. Not a new idea though.

  9. Joe in Australia says:

    The quoted cost is excessive: it would take a large mold, but in volume it shouldn’t cost more than a euro or two. A better shape would have a hexagonal footprint for two reasons: it would be stiffer because the ribs would help support it, and hexagons can be placed without wasting space between them. Apart from that, great idea.

  10. Ronadl de boer says:

    You bring this like it’s something new and could change the world but this sollar stills are OLD and have not changed the world yet. Mainly because of the poor efficiency. It’s handy when you are in trouble but not for daily needs.

    Look: a design from 1978

  11. Many would-be inventors have great ideas, but are they truly practical. I know one thing: A way will come along where there is a purpose and great need.

  12. Pingback: NewsEco: Cool water, hot solar and eco-villages - Blog.HowYouEco - Green. Health. Life.

  13. Pingback: ????So??? » ??????(Watercone)

  14. Ken Rose says:

    The cheap option is to dig a hole in the ground.
    Tip some salt water in the hole to moisten the soil.
    Put a piece of plastic sheeting over it with rocks holding it down around the edge and a single rock suspended in the center to make a reverse cone with a cup in the middle under the rock to catch the water that collects on the plastic sheet.

    The same Idea can be produced with a tent style setup of plastic sheets and a guttering under each side to catch the water. This can be made very large to produce a lot of water.

  15. Ruggy says:


    But they should make a version out of something that doesn’t cloud up eventually. Use LEXAN or maybe safety glass. The plastic will be around for centuries as waste anyway, so why not make one which will function for the very long term?

  16. Julian says:

    Yes amazing, finally somebody’s done something useful but where the fracking hell can I buy this watercone from, does anybody in this whole wide world know? Coz I sure as hell would prefer the real thing instead of looking at the damn thing on my monitor. It’s of aboslutely no bloody use to me as a picture, so please if anybody out there knows where I could buy this from do let me know.

  17. Derek Markham says:

    Julian –

    From the Watercone website:

    For general information and pricing please contact:

    Dr. Hendrik Müller-Holst

    Tel: +49-(0)89-14729617
    Fax: +49-(0)89-14729672
    Email: mueller-holst@mage-watermanagement.com

  18. piriz felipe says:

    muy buena idea, pero les comento que yo tengo una similar que solo necesita del aire.. lo unico que me falta es un poco de dinero para fabricarla— les informo desde argentina.corrientes…

  19. tony says:

    my comments on comments in this blog :

    1. $ 20 bucks for this thing is nothing to complain about, you still pony up to the bar for a pint of your favorite ale, yes ?

    2.If you have a choice between drinking dirty swamp water or clean hormone active water which one will you choose ?

    3. When you are hot and thirsty you don’t give a damm about BPA. Ya, lets make them out of shatter proof pyrex, that cost’s 100 times as much, something that poor 3rd world country folk can buy !

    4. This next one is a no brainer / 1 still makes 1 liter of water, 100 stills makes 100 liters of water, that enough water to boil your weenies in ?

    M comment : Outstanding invention, if I had 1% of Bill Gates money, I would buy a zillion of these and distribute them all over the globe for free.

Leave a Reply

Back to Top ↑