A girl in Kenya's Kisii District draws water from a local spring that has been protected through concrete sealing. (Photo courtesy of Kisii District Public Health Office) 

Living near safe drinking water is not the same as drinking safe water. Some have argued that anything short of pumping it directly to the kitchen won’t have any health benefits. “Even if the water is clean when you get it from the spring, it can become contaminated in storage at home,” says Michael Kremer, Gates Professor of Developing Societies in the economics department at Harvard University. In the first randomized evaluation of the health effects of improving water sources alone, without any simultaneous sanitation changes, Kremer and colleagues found that “clean water does make a difference in terms of reducing diarrhea” despite recontamination on the way to the drinking glass.

Kremer followed a spring protection project in rural western Kenya in 2005. “A typical unprotected spring may be like a mud pit in the dry season and in the wet season, a small pond,” says Karen Levy of Innovations for Poverty Action, the nonprofit that evaluated the project. “Because there’s no clean edge, it’s very easy for it to get contaminated when people and livestock come and wade in the water.” Spring protection seals off the source and encases it in concrete, so that the water flows out through a pipe above ground, where people collect it in jerry cans.

Household surveys showed that this does have a health benefit: Spring protection reduces child diarrhea by a quarter. But it could do better. Although the new infrastructure improved water quality at the source by 66 percent on average, it improved water quality at home by only 24 percent. Levels of education and sanitation in the household seemed to make no difference to recontamination, but ongoing research into dispensing chlorine at the springs looks promising.

Protecting a spring costs about $1,000. Although most of the springs in this study were on private land, almost none of the landowners had invested in protection—in part because local custom (and sometimes law) does not permit charging for water. Would allowing landowners to profit from their springs get clean drinking water to more people? Or would neighbors just walk farther to get free dirty water? The researchers created a mathematical model of the trade-offs and found that at current income levels rural western Kenyans are better off with the existing social norm.

“We’ve collectively spent billions of dollars on development aid over many decades, and there’s strikingly little evidence about what works and what doesn’t,” says Levy. This rigorous analysis of the benefits of spring protection show that “it’s good, it gets people cleaner water, and it reduces diarrhea,” says Kremer. “As long as enough people are using the water source, it’s quite cost-effective. I think it’s a good buy and I encourage NGOs to do it.”

Michael Kremer, Jessica Leino, Edward Miguel, and Alix Peterson Zwane, “Spring Cleaning: Rural Water Impacts, Valuation, and Property Rights Institutions,” The Quarterly Journal of Economics 126, 2011.

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