KOPO addresses pressing health and social needs of the developing world through context-appropriate products. Using only sunlight, our plastic jug called the Kopo Can kills diarrheal diseases in river, rain, and pond water. Heating and UV from the sun kill all the pathogens that cause typhoid, dysentery, cholera, and other waterborne diseases, so the resulting water meets international drinking water standards from the World Health Organization. We designed the Kopo Can with local input to fit the cultural norms for collecting water in Sub-Saharan Africa and India. An indicator is integrated to show then the water’s ready to drink.