The GLAAS 2009/2010 cycle integrated and analysed data from several different existing sources, including global data on sanitation and drinking-water coverage, donor aid flows, economic and development indicators, health indicator data, and data from regional sector and multi-sector assessments. In addition, GLAAS 2009/2010 involved a data gathering process for both countries and external support agencies to fill key knowledge gaps. Data collection took place from late 2009 to early 2010.

Country survey

To avoid duplication of effort, data collection at countries occurred in full collaboration with other international partners. For instance, in Africa the data collection was performed in collaboration with the World Bank's Water and Sanitation Program Country Status Overview (CSO) initiative, and in Asia with UNESCAP Water Security initiatives. Countries were requested to formally participate through WHO country offices and through their respective government contacts.

For nearly all sub-Saharan African countries, the following country survey questionnaire was used:

For all other countries, the following country survey questionnaire was used:

External support agency (ESA) survey

To address information gaps concerning external development aid, the GLAAS 2009/2010 cycle also included gathering data from bi-lateral and multi-lateral donors, NGOs, private foundations and international agencies. This data gathering effort recognized that a large amount of aid flow data is already available through existing sources. WHO worked in close collaboration with the Organisation for Economic Co-operation and Development (OECD) to make the best use of existing sanitation and drinking-water aid flow data, as most donors report to the OECD Creditor Reporting System (CRS). For external support agencies that already report sanitation and drinking-water sector aid flows to the OECD CRS, the following questionnaire was used to augment existing data: