Mark Kinver BBC News 12 Jun 12;
The world's top river basin regions have a vital role in the future in terms of sustaining economic growth in the future, a report has suggested.
However, current projections show that seven of the top 10 areas are currently using unsustainable volumes of water.
A UN report said the global target of halving the number of people in the world without access to safe drinking water was achieved in March 2012.
The report was commissioned by HSBC, WWF, Earthwatch and WaterAid.
The document, Exploring the Links between Water and Economic Growth, produced by Frontier Economics, recorded that almost 800 million remained without access to safe drinking water, while 2.5bn were without basic access to sanitation.
The report's authors estimate that nations would see their GDP improve by up to 15% if the global Millennium Development Targets were achieved.
A report published by the UN in March said the international community had acheived the goal of halving the number of people without access to safe drinking water.
In the past 20 years, two billion people have gained access to improved drinking water.
However, it acknowledged that global targets to improve sanitation were unlikely to be met by the 2015 deadline.
The Millennium Development Goal (MDG) lists 75% of the world's population benefiting from improved sanitation, yet figures suggest that only 63% of the world's population currently have improved sanitation access, a figure projected to increase only to 67% by 2015.
This means that 2.5bn people are still without the level of sanitation outlined in the MDGs.
The report by Frontier Economics listed a number of avenues that need to be addressed in order for the "water challenge" to be addressed.
As well as improving the access to drinking water and sanitation, it also listed the need for great efficiency in the way water is consumed within agriculture, industry and domestic sectors.
Other findings included:
By 2050, the top 10 river basins (by population) are forecast to produce 25% of global GDP - greater than the combined economic output of the US, Japan and Germany
But without effective management, seven out of the 10 regions will be consuming an unsustainable volume of water by 2050.
"We argue that the social and economic gains show that the investment in water and sanitation is critical," explained Barbara Frost, chief executive of WaterAid.
"This report really picks up that up and shows that the return on each dollar invested is about, on average, five dollars."
Ms Frost added that recent estimates showed that about 40% of the world's population did not have adequate sanitation.
Common agenda
"Over the past 30 years, there have been so many initiatives - sometimes these have not been particularly joined-up," Ms Frost explained.
"There does need to be a clear and common agenda on water security, one that puts people that the heart of this as well."
She said that she hoped the forthcoming Rio Summit would place greater "emphasis on investment where the need is greatest".
"In other words, this is where the MDGs are furthest off track," Ms Frost told BBC News.
"The UN needs to play a strong role as a convener or co-ordinator of global acitivities, both in terms of promoting human development as well as sustainable and environmental development."
She said that progress was made in China and Asia, but extra effort was still required in sub-Saharan Africa.
Global banking giant HSBC is using the report as a platform to launch a five-year $100m programme that hopes to address a number of issues, including improving sanitation for more than a million people.
