What are the reasons for the present crisis?

Many factors are responsible. To mention but a few: increased and unsustainable agricultural and industrial use of water, deforestation and land-degradation that seriously change the water cycle, over-consumption and waste, pollution and population growth. But the crisis is aggravated by the prevailing economic system. Public and community control of water supply has drastically diminished over recent decades and years. Increasingly water is treated as a commercial good subject to market conditions. Many cases can be cited where privatisation of water resources has deprived the poor from access to water.

Beyond scarcity: The UNDP Human Development Report on the water crisis

That lacking access to water cannot be seen just as a result of water scarcity is also reflected in the title and focus of the United Nation's Human Development Report 2006. Entirely dedicated to the crisis in water and sanitation, the report is titled "Beyond scarcity. Power, poverty and the global water crisis."