Biosand Water Filter (610.7 KB) Access to clean drinking water remains one of the greatest challenges in the world. The BioSand Filter is one method that can be used for purifying water at the household level. With this filter, contaminated water is filtered through a natural biological layer and then layers of sand, pebbles and stones. The BioSand Filter can be made using local materials and is a low-cost system that removes suspended sediments and other impurities from water in order to make it safer for human consumption. Copyright © ECHO 2007. All rights reserved. This document may be reproduced for training purposes if distributed free of charge or at cost and credit is given to ECHO.