It works like a coffee percolator turned upside down: Eliodomestico, a solar-powered water distiller for coastal populations in the developing world. Created by Italian designer Gabriele Diamanti, it is easy to use. The container on the top is filled with saltwater in the morning. By evening, the water has evaporated and condensed again into the container on the bottom, producing 5 liters of drinkable water. This novel water distiller made of inexpensive clay needs no electricity and should cost around $50 (€38) – about half the price, but nearly 70% more effective than most existing models. Eliodomestico is an open-source project that allows anyone to build a copy of this saltwater treatment equipment.