Sunday, June 14, 2015


I have built and sold and installed solar water distillers for years. It is a wonderful feeling to build something that can take nasty or polluted water and turn it into something absolutely pure and drinkable! So how do you build a solar water distiller?

Here are some tips on how it works...

First of all you want to understand how a solar water distiller, also called a solar still, actually runs. It is basically a wide and low-profile 'box' that has glass on top at a slightly sloped (about 10 degrees) angle. The bottom of this box inside will be black so as to absorb as much of the sun's rays as possible. The water is inserted through a side tube (you can use a water hose or gravity-fill using a bucket and tube) into a thin layer, maybe 1"-2" in depth.

As the sun heats up the water it will start to evaporate, and will begain condensing onto the cooler glass above, and then trickle down underneath the glass, draining into a 1" CPVC tube cut in half lengthwise, which acts as a water trough. The condensed/distilled water then drains out an exit tube into your water collection vessel (usually glass since plastic dioxins can be carcinogenic).

That's all there is to making solar distilled water!

However, making the box with food-safe materials is a MUST! There are different ways to do this. Plus the box needs to be insulated well so as to not lose heat. Basically, this is similar to a solar oven design, but holds water, and gets hot enough to burn you if you were to touch it. It does not boil--nor do you want it to boil since that is a forced method and tastes metalic and is acidic. Natural solar water distilled water is softer and alkaline, if not neutral in pH.

There are a lot of tricks to choosing materials, but items ranging from glass to solar kits that have special food-grade silicone manufactured liner are included. You can also use a food-grade silicone in the tubes (special order) and smear it onto the inside of the box yourself. Some people use high-grade stainless steel but this tends to be expensive and can pit/erode over time since distilled water has NOTHING in it, and absorbs whatever it touches.

I cover more details in my book below:

You can learn all about the layers and items needed (plus other solar projects!) in the full intro in my book:
Passive Solar Energy House Projects: A How-To Guide
Hard copy $15.00 / Electronic $9.99 (Kindle)

I no longer sell solar water distillers, however you can click on the links below to purchase them directly from the websites/companies:

Solaqua Solar still produces 1 1/2 gal/day for 1-2 people per still (no electricity, on-site, no running water necessary)

Suns-River stills produce 4x the amount of water than a passive still using the sun and an electric pump - these are excellent for communities

Flo-Onics Stills used to produce 100 gal/day to 250,000 gal/day for communities/groups/towns but last time I checked I think the company was defunked.

For solar water distiller construction plans you can obtain them through the El Paso Solar Energy Association or

Enjoy learning more and making your own solar water distiller!

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