Since the early 1970s tens of millions of shallow tube wells have been installed in Bangladesh and India, resulting in a vast yet silent disaster: these wells draw from arsenic-contaminated aquifers. Recent studies report that up to 20% of all adult deaths in Bangladesh are now arsenic-related. Berkeley researchers have developed a technology, ElectroChemical Arsenic Remediation (ECAR), that robustly, reliably, and affordably produces arsenic-safe water within a sustainable and scalable business model. ECAR uses an innovative method: a small electric charge creates rust particles from ordinary steel plates which bind to arsenic, allowing for effective filtration. The technology is designed to be robust and low-maintenance enough to work in deep rural areas with almost no tech backup or support.