This disjunction could have large implications for public health planning. In many water-insecure places, diarrheal disease is still a leading cause of death—especially for children, of whom some 1.5 million succumb to these infections. Most of those illnesses result from contact with bacteria, viruses or parasites, often through unclean water. A recent study in Environmental Health showed that access to clean water could reduce childhood mortality by 1.17 deaths per 1,000 children, which is a large number of preventable deaths for the millions of children who lack access to improved water—and millions more who apparently lack access to fully safe water supplies.
These preventable diseases also cost countries dearly in lost productivity. Poor sanitation can demand high environmental cleanup costs, and are a major drag on economic growth, notes Jaehyang So, manager of the Water and Sanitation Program at the World Bank.
Gathering data about the type of water source—tap, drainage ditch, borehole, etcetera—is a lot easier than performing formal water quality tests, which is one of the reasons the U.N. goals focused on improving water sources.
"The problem is that there is not really any good, objective water quality test" that can easily be performed in remote areas of developing countries, says Stephen Gundry, professor of environmental engineering at the University of Bristol who co-authored the WHO Bulletin paper.
The U.N. is not blind to this disparity. Many experts at the organization "have let Mr. Ban know in no uncertain terms that his office has badly understated the scale of the drinking water crisis," environmental analyst Roger Harrabin wrote earlier this month in his column for BBC News.
"These targets are set in a very political environment," says Sanjay Wijesekera, chief of the U.N. Children's Fund's (UNICEF) Water, Sanitation and Hygiene Programme division. And once the goals are established, he and others working on the challenges are tasked to try to help as many countries as possible meet them.
One of the biggest breakdowns between improved and safe water occurs almost imperceptibly over time. Creating an improved water source does vastly increase the odds that water will be safe. But if pipes, wells and other improvements are not maintained over time, they can become damaged or compromised, allowing bacterial contamination in.
With the focus on installing pipes, wells and other improvements, localities and organizations have not always kept up the gains they have made. Wijesekera points out that UNICEF programs, such as those in eastern and southern Africa, emphasize sustainable water improvements. These initiatives have an annual sustainability check to make sure facilities have both technical and financial support to keep them running safely. But as Gundry notes, continued maintenance often does not garner extra credit or funds, allowing once-safe installations to fall into disrepair.
All of these new pipes and wells "have been very effective in bumping up the numbers" for the MDGs, Gundry says. But the bottom line is that U.N. officials "focused on an indicator that doesn't tell the whole story," he notes. "They just accepted that an improved source is a safe source, which it isn't, of course.”
Additionally, many people still have to transport water from a source back to their homes—a period when contamination can occur. Contamination is likely "somewhere along the way," Wijesekera says, from unsanitary containers or handling. The World Bank's So notes that some 40 percent of home water samples studied in India that were clean upon collection had been contaminated by the time they were ready for consumption at the home. But measuring those levels on a broad scale would mean testing water in homes, which is even more difficult than the area testing.