www.mdpi.com/journal/ijerph Article Global Access to Safe Water: Accounting for Water Quality and the Resulting Impact on MDG Progress

Abstract: Monitoring of progress towards the Millennium Development Goal (MDG) drinking water target relies on classification of water sources as “improved ” or “unimproved ” as an indicator for water safety. We adjust the current Joint Monitoring Programme (JMP) estimate by accounting for microbial water quality and sanitary risk using the only-nationally representative water quality data currently available, that from the WHO and UNICEF “Rapid Assessment of Drinking Water Quality”. A principal components analysis (PCA) of national environmental and development indicators was used to create models that predicted, for most countries, the proportions of piped and of other-improved water supplies that are faecally contaminated; and of these sources, the proportions that lack basic sanitary protection against contamination. We estimate that 1.8 billion people (28 % of the global population) used unsafe water in 2010. The 2010 JMP estimate is that 783 million people (11%) use unimproved sources. Our estimates revise the 1990 baseline from 23 % to 37%, and the target from 12 % to 18%, resulting in a shortfall of 10 % of the global population towards the MDG target in 2010. In contrast, using the indicator “use of an improved source ” suggests that the MDG target for drinking