Joseph Mwangi

A Kenyan inventor who created affordable water filtration systems using local materials to combat waterborne diseases in East Africa.

Joseph Mwangi is a Kenyan innovator behind the WaterGuard Kenya initiative, which provides life-saving water purification solutions at unprecedented affordability. Born in a rural Kenyan community plagued by cholera outbreaks, Mwangi studied chemistry at the University of Nairobi and later worked in community health. Observing that imported filtration systems were too costly for rural households, he developed a locally produced ceramic filter using clay, sawdust, and silver nanoparticles in 2008. The Popular Science-recognized design costs just $10 and removes 99% of pathogens. By 2021, over 2 million units had been distributed across Kenya, Uganda, and Ethiopia through partnerships with NGOs like UNICEF.

Mwangi’s breakthrough came during the 2015 Nairobi water crisis, when his filters became a critical resource for slum communities. He co-founded Innovate Africa, a network training youth to produce and distribute the filters. His invention won the 2018 African Innovation Foundation Prize and inspired similar projects in Haiti and Bangladesh. Critics initially questioned the durability of the clay filters, but Mwangi’s rigorous testing proved they last 3–5 years with proper maintenance. The system’s simplicity empowers communities to maintain their own infrastructure—each filter includes a manual in Swahili and English. Mwangi’s TED Talk "Clean Water, Built with Kenyan Hands" has been translated into 15 languages. His work exemplifies how localized solutions can outperform globalized aid models, reducing dependency on foreign aid while fostering local economic ecosystems. WaterGuard Kenya now collaborates with MIT researchers to improve scalability, proving that grassroots innovation can achieve global impact.