• 828 million people live in slums or informal settlements that are scattered around the world’s cities; the biggest challenge is to provide these people with adequate water and sanitation facilities.
• The urban poor pay up to 50 times more for a liter of water than their richer neighbours, since they often have to buy their water from private vendors.
• Due to rapid urbanization, cities face a growing demand for water and sanitation services. To meet this demand, cities are going deeper and further, which leads to over-exploitation of water resources.
• Pollution typically refers to chemicals or other substances in concentrations greater than would occur under natural conditions.
• Every day, 2 million tons of human waste are disposed of in water courses.
• In many cities, especially in the developing world, the lack of convenient wastewater treatment and drainage facilities lead to pollution of the ground-and surface water resources.
• Lack of convenient sanitation and safe water supply in cities leads to serious health problems.
• Inadequate sanitation facilities often cause contamination of drinking water.
• After heavy rain, stormwater washes human waste, mainly from informal settlements lacking minimum facilities, into the open drinking water sources of the poor.
• Contaminated drinking water results in cholera epidemics, faecal-oral diseases such as diarrhoea, and outbreaks of malaria.
• While malaria was often considered a rural disease, it is now among the main causes of illness and death in many urban areas.
• Leakage -loss- rates of 50% are not uncommon in urban distribution systems.
• Some 250 to 500 million m3 of drinking water gets lost in many mega cities each year.
• Saving this amount could provide an additional 10 to 20 million people with drinking water in each mega city.

The section “Did You Know…?” is taken from the UN-Water Decade Programme on Advocacy and Communication (UNW-DPAC) publication “Water and Cities: Facts and Figures“.