DIY: Make Water Safe With This Solar Powered Device


Water is key to our survival and that is why we need to have access to a clean source. We all know that tap water isn’t that good, and in my opinion this is due to a secret pact between the government and big corporations, but that’s a tale for another time.

So what to do to make sure the water you’re drinking is safe? Many would suggest a filter, but that takes care only of biological hazards, particularly minerals and radiation. Excess salt or harmful chemicals don’t get filtered out.

The solution is to distill the water. Distillation is a simple process. You heat up the water to the point where it evaporates, then that vapor is captured and cooled, turning back into water.

Through this process the water becomes crystal clear and pure, with nothing harmful in it. This is because only chemicals with lower vapor point than water could evaporate alongside it. There are few elements that would be normally found in liquid state at typical ambient temperatures with that property.

Now the down side of this process is that it takes time and constant heat must be applied in order to evaporate the water. Luckily we have a free, constant and unlimited heat source at our disposal : the sun.

We are going to build a solar still that you can use year round to ensure that the water you drink is 100% safe.

How To Build The System

The idea is simple : you make a glass-covered box(painted black on the inside), place a pan of water inside it and place the still in the sun. Sunlight enters the box through the glass, heats the water which evaporates. Then once the water vapors hit the glass, condense form and it runs down to a collection tube.

Sounds easy enough? Well it is. Now let’s get to work.

What you will need:

3/4 x 4′ x 8′ sheet of BC exterior plywood ( 1 ) – Link –

11/2″ galvanized hinges ( 2 ) – Link –

10″ x 15″ glass baking pans ( 2 ) – Link –

1″ PEX tubing – Link –

2 x 4 x 8′ pressure treated lumber – Link –

271/4″ x 22″ x 1/8″ glass

11/4 ” , 2″, 21/2″ deck screws – LinkLinkLink

Circular saw

Speed square

Drill with bits


Caulk gun

Silicone caulk

Razor knife


Tape measure

Self-adhesive weatherseal ( 8′) – Link –

Knob/drawer pull

High temperature black pain – Link –

Wood glue – Link –

Painter’s tape

Step by step assembly


1. First things first. We need to cut the plywood. Follow the measurements found in the table below. Cut the angled end pieces with a circular saw or table saw set to a 9 degree angle.


2. Cut the insulation the same size as the plywood base, then screw both to the 2 x 4 supports with 2 1/2″ screws.

3. Screw the first layer of front and side pieces to the base and to each other, then add the back piece. Predrill the screws with a countersink bit.

4. Glue and screw the remaining front and side pieces on, using clamps to hold them together as you predrill and screw. Use 1 1/4″ screws to laminate the pieces together and 2″ screws to join the corners.

5. Glue and screw the hinged door pieces together, aligning the bottom and side edges, then set the door in position and screw on the hinges. Add a pull or knob at the center.

6. Paint the inside of the box with black high-temperature paint. Cover the back and the door with reflective foil glued with contact cement. Let the paint dry for several days so that all the solvents evaporate off.

7. Apply weatherseal around the edges of the hinged door to make the door airtight.

8. Drill a hole for the PEX drain. The top of the PEX is 1/2″ down from the top edge. Clamp a scrap piece to the inside so the drill bit doesn’t splinter the wood when it goes through.

9. Mark the first 19″ of PEX, then cut it in half with a utility knife. Score it lightly at first to establish the cut lines.

10. Drill three 1/8″ holes in the side of the PEX for screws, then insert the PEX through the hole. Butt it tight against the other side, then screw it in place, sloping it about 1/4″.

11. Wipe a thick bead of silicone caulk along the top edge of the PEX to seal it against the plywood.

12. Shim the box level and tack a temporary stop to the top edge to make it easy to place the glass without smearing the caulk. Spread a generous bead of caulk on all the edges, then lay the glass in place. Tape it down around the edges with painter’s tape, then let it set up overnight.

After this you’re all set to start distilling your water and make it crystal-clean and safe to drink. And the best part: it’s free.





What other methods would you use to distill water? Share your thoughts in the comment section below.


This article has 3 Comments

  1. I use a dehydrator ($160 from Home Depot) and run it when the dew point is within about 10 degrees or less of the ambient temperature. The condenser plate runs about 12° cooler than ambient thus water is condensed. Without a dew point temp measurement I use the web wx and then run the humidifier in the wee hours prior to and just after dawn when the ambient temp is lowest. When the cars in the drive have wet, dew covered windshields is another good clue for when to run the humidifier.

    At ~12 cents per kW/hour that water costs on the order of 30 cents to “make”. A $10 water tester will show that this water has less than 10 ppm TDS (total Dissolved Solids) which is better than RainSoft water.
    Ed, San Diego

  2. I am wondering whether you have to tilt the glass at a certain angle so that the condensation falls directly into the pipe. I have very little experience with building, so maybe this is the purpose of the angled end pieces? Please forgive if this is a dumb question. Also wondering how far in from the side the pipe is inset. Is it flush against the end?
    Thanks for this idea! I am going to give it a shot.

  3. I am dreaming of making well water consumable to humans and plants as well. I thought of using Alkaline to neutralize the acidity in our chlorinated tap water and other chemicals in our well water. This article opens another way of water purification which is good for human consumption.
    The most difficult part for me will be to get the materials for construction and incorporating it to the well water plant. Make it more simple to absorb the sun to produce heat for evaporation and subsequent transformation of the residue and eliminating waste from the system.


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