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

Using data from an 18-month randomized trial, we estimate large and sustained impacts on water purification and child health of a program providing monthly coupons for free water treatment solution (diluted chlorine) 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. That is because only 40% of households make use of 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 free chlorine beneficiaries. Non- use of free chlorine is driven by households who have a protected water source and those who report that chlorine makes water taste bad