Because of the heavily polluted water, the idea of swimming in Copenhagen’s harbors was unthinkable fifty years ago. However, by investing in the complete modernization of the sewage system, adopting a cleaning program, and commissioning a strong urban design to create a recreational space, the water quality improved and the City was able to open the public harbor baths. The water has been safe for bathing since 2002, and this was possible due to a collaboration between partners, including researchers, academics, architects, planners, engineers, municipal and private sector organizations who led the mechanical, biological and chemical wastewater treatment, and the decoupling of rainwater.
Demand of water
Copenhagen has been working to meet the rising demand for water. By adopting innovative technologies and policies, it has been possible to protect groundwater resources, limit the losses in the drinking water supply system and reduce drinking water consumption. Some of the solutions are the management of water resources by the use of new technologies to monitor and prevent leaks; water purification and groundwater modeling and protection; and behavior changes measured by water meters and pricing mechanisms to reduce wasteful consumption. The latter was done by the installation of individual water meters, and the consumption fell remarkably by an average of 26%.
 Copenhagen Solutions for Sustainable Cities, 2012