In 2008, the concept of a global assessment report for the sanitation and drinking-water sectors was pilot-tested by WHO on behalf of UN-Water. This pilot, or 'proof of concept,' was launched in New York in September 2008 during the UN High Level Event on the Millennium Development Goals at a side event chaired by the UN Secretary General Ban Ki-moon.

The pilot report highlights the existence of significant knowledge gaps and the fact that the sanitation and drinking-water sectors lack a global, periodic, and comprehensive sector analysis, which is able to speak to and influence high level policy-makers.