Access to water and sanitation are "critically important" and intertwined, she noted. "Improving the quality of water at the source may have little effect on a household's health if, for example, that water is re-contaminated during storage by family members with inadequate hygiene practices. On the other hand, without a sufficient quantity available to the household, it is exceedingly difficult to practice good hygiene, such as hand washing."
In addition to health benefits, clean water and sanitation also have a positive effect on education and the economy, Davis added. "Having sanitation facilities in schools has a differential impact on girls' attendance at school," she said, noting that school attendance among girls goes up when there are separate sanitation facilities, especially after they reach puberty.
Better water and sanitation also can reduce the time that women and children spend fetching clean water, giving them more time to attend school or engage in other productive activities, she noted.
At the national level, economic development strategies, such as attracting foreign investment and tourism, often rely on good water quality and sanitation, Davis said. However, wealth does not necessarily translate into improved water and sanitation services. "Tracking the progress of countries from 1990 to 2004, we do see that countries that are at risk of missing either or both targets are more likely to be in the lowest income categories," she said. "They are a