Billions of the world's poor still lack access to basic water and sanitation services, yet many of them can count mobile phones among their possessions. Water and sanitation practitioners have begun to tap the potential of these phones as tools to improve water, sanitation, and hygiene (WASH) services. This report from the Pacific Institute and Nexleaf Analytics assesses how these “mWASH” solutions can amass and disseminate information quickly and thoroughly – directly to or from the underserved populations most in need of service from water providers.