Expanding Access to Clean Water for the Rural Poor: Experimental Evidence from Malawi

Data from an 18-month randomized trial show large and sustained impacts on water purification and child health of a program providing monthly coupons for free water treatment solution to households with young children. The program is more effective and much more cost effective than asking Community Health Workers (CHWs) to distribute free chlorine to households during routine monthly visits. This is because only 40 percent of households use free chlorine, targeting through CHWs is worse than self-targeting through coupon redemption, and water treatment promotion by CHWs does not increase chlorine use among beneficiaries of free chlorine.