DIY Solar-Powered Water Purifier

This simple yet ingenious device harnesses the power of the sun to purify water using a process called solar distillation. It's a great way to ensure you always have access to clean water, even if you're far from civilization or experiencing a power outage.

How it works

The basic principle behind a solar still is simple: evaporation and condensation. The sun's heat causes water to evaporate from a contaminated water source. The water vapor rises and condenses on a cool surface, forming pure water droplets that can be collected. As sunlight heats the box, moisture rises and condenses on the cooler, slanted glass top. Droplets then slide down into a collector tube and drain into a storage container.

Building your DIY solar still box

The box is constructed from ¾" plywood, painted black inside to maximize heat absorption. Doubling the sidewalls helps insulate and prevent warping. A rear door provides access, and a clear glass sheet covers the top.

Choosing the right water container inside is key. Heat and contaminants can degrade plastics or corrode metals. Glass or stainless steel are best. Alternatively, coat the interior with two or three layers of black, food-safe silicone caulk using a taping knife. Once cured, the silicone is waterproof and heat-resistant.

We used two 10x15" glass baking pans, each holding about 4 quarts. They’re affordable, safe, easy to clean, and scalable—just expand the box and add more pans to increase capacity.

As the sun heats the water, it evaporates, condenses on the glass, and flows to the collection tube—made from 1" PEX or stainless steel. Avoid materials that alter the water’s taste—boil a sample and test it before use.

This simple setup turns salty or dirty water into clean, drinkable distilled water using nothing but sunlight.

Additional considerations

• Production rate. The amount of purified water produced by a solar still will vary depending on factors such as sunlight intensity, temperature, and the size of the still.

• Alternative designs. There are many different designs for solar stills. You can find more complex designs online that may be more efficient or produce more water.

Conclusion

Building a DIY solar-powered water purifier is a great way to ensure you always have access to clean drinking water. It's a simple, low-cost solution that can be a lifesaver in emergency situations.