This stagnation has several causes:

• the restricted level of investments within the sector, especially in the third world. Annually an estimated 25 billion euro needs to be invested to achieve the Millennium Development Goals for water.
• the population growth. The absolute number of people who have access to drinking water increases but in terms of percentage there is no improvement. This phenomenon counts especially in the big cities in Asia and Latin America, where water supplies cannot keep up with the rapid population expansion.
• the bad management and maintenance of many water pipes and wells. As a result a lot of financial resources and energy have to be invested in reparations.
• the redefining of the role of the State, especially in the South. In the eighties many governments assumed with changing success the distribution of drinking water. However, the Structural Adjustment Programmes (SAP's) that were imposed by the World Bank and the International Monetary Fund obliged most governments to reduce their social services. In the current decentralisation process local governments in the South now become responsible for the provision of drinking water, but most do not have the resources nor the required know-how for it.
• the cost of drinking water is often too expensive for certain population groups in the South in comparison with their income. Consequently too big a share of the income is spent on water (sometimes up to 20 %). 
• the frequently missing access to sanitary installations and a good hygiene. Of course clean water is essential for personal and environmental hygiene. But somebody who suddenly gets access to drinking water does not automatically change his or her hygienical behaviour. As a consequence diseases such as cholera, worms and diarrhoea can quietly continue to proliferate. The number of deaths and cases of a disease as a result of "water-related" sicknesses can only be reduced significantly by simultaneously making drinking water available, foreseeing sufficient sanitary installations and adapting hygienic practices.