The number of people who lack access to safer drinking water has fallen drastically over the last two decades but the progress has all too often sidelined the poor, the United Nations has said.
A new report released on Thursday underscores a recent report on efforts to improve drinking water and sanitation.
The World Health Organisation (WHO) and UNICEF said 89 percent of the globe’s population had access to improved water supplies at the end of 2012.
When we fail to provide equal access to improved water sources and sanitation we are failing the poorest and the most vulnerable children and their families.
But despite that progress, 748 million people - roughly half of them in Sub-Saharan Africa and most of the rest in Asia - still used unimproved water sources.
Most of those lived in rural areas, the report said, where access to clean water could limit the spread of diseases such as cholera, hepatits A, dysentery, typhoid and diarrhoea.
The WHO-UNICEF study also examined access to what are known as "improved sanitation facilities", which separate human excreta from human contact.
By the end of 2012, 64 percent of the global population used such facilities, a rise of 15 percentage points since 1990, showing there had been substantial progress in narrowing the water and sanitation gap between urban centres - home to half the global population - and rural areas.
On the sanitation front, the proportion of urban dwellers with access rose by four points over the same period, reaching 80 percent, it found.
There were also improvements in rural areas, with the proportion of inhabitants with access to improved sanitation jumping from 28 to 47 percent.
But that figure masked major disparities, underlined Maria Neira, the WHO's public health chief.
"Progress on rural sanitation - where it has occurred - has primarily benefitted richer people, increasing inequalities," she said.
In addition to the disparities between urban and rural areas, there are often also striking differences in access within towns and cities, with the poor far less likely to be covered.
"When we fail to provide equal access to improved water sources and sanitation we are failing the poorest and the most vulnerable children and their families," said Sanjay Wijesekera, head of water, sanitation and hygiene at UNICEF.