The growing demands for affordable and applicable technologies for decentralized safe drinking water provision have instigated technical innovations in the water filtration industry. Adsorptive filtration appears to be the most affordable, resilient, and socially acceptable solution for households and small communities worldwide. However, water filtration devices have not yet been widely implemented due to lack of awareness for the efficiency of such systems using locally available materials. Water filtration has the potential to secure universal access to safe drinking water by 2030. This special issue has elucidated the applicability, benefits, constraints, effectiveness, and limitations of metallic iron as filter material for safe drinking water provision. Tools to make rainwater a primary water source are also presented together with ways to transform existing centralized water management systems into decentralized ones (sectorization). The knowledge is applicable to a wide variety of situations on a global scale.