Supplying clean water to households is perhaps the most pressing challenge facing governments across Southeast Asia. This study from Vietnam has looked at the water supply options available in the country's Mekong Delta. It finds that ground water extraction represents the best alternative both in terms of its popularity and its cleanliness. The report also finds that the best method to supply this resource is through ground water supply units or GSUs. These extract water from a deeper level than tube wells (the other main method of extracting ground water) and are the most environmentally sustainable option. To get people to switch to this supply source (for which they have to pay a fee) the report recommends that the GSU option should he promoted to every household not currently using it, especially private tube-well owners.