While there are various ways to purify water, among the cheapest and most effective means available in Southeast Asia involves passing water through a simple ceramic filter. Shaped like a flowerpot, the filter is saturated with an industrial concentration of colloidal silver. Made from clay and sawdust, the filter blocks larger water-borne particles while the microbiological inhibiting properties of the colloidal silver inactivate bacteria small enough to pass through the filter's tiny holes. Though basic, such filtration units have been tested to be 98-100% effective.

The pictured unit was purchased by SEN for a family in Stung Hau. The unit includes a plastic receptacle which holds the filter. Water stored in large containers is poured into the filter, slowly draining into the larger plastic receptacle. Once it passes through the filter, the water is safe to drink.