Field test of a silver-impregnated ceramic water filter

The silver-impregnated Ceramic Water Purifier (CWP) is a low-cost household water filter that removes micro-biological contamination at the point of use. One thousand CWPs were distributed in twelve Cambodian villages to test their effectiveness under conditions of rural household use. Water quality tests (n=686) were conducted to measure filter performance. A control group comparison survey (n=201) and a baseline and follow-up survey (n=1,000) measured impacts on household health and expenses. Ninety-nine percent of CWPs produced water meeting WHO ‘low risk’ guidelines or better (10 or fewer E. coli per 100 ml). Households that used CWPs experienced significantly lower incidence of diarrhoea than households without CWPs. Households that had previously boiled their drinking water experienced savings in time and expenses after using the CWP. The CWP’s low production cost (US$5.50) opens the possibility of reaching large numbers of the rural poor through sustainable market channels.