Contaminated water can be purified for drinking purposes using bio-sand filtration, which removes organisms responsible for diseases spread by water such as cholera, typhoid fever, diarrhea and amoebic dysentery, and also strain out fine particles which cause cloudiness. Durable bio-sand filters manufactured for household use are constructed from cement using a steel mold. The cement container is designed to allow water to flow through a column of sand at a predetermined rate to remove contaminants in water. A biological layer that forms on the surface of the sand, known as the schmutzdecke, comprises a layer that trap and break down organic matter, including disease-causing organisms in water. The combination of sand and the biologic layer purifies water at a rate of 12-18 liters per hour, which can serve the average families’ daily needs.