Most of big cities water pipe networks have been build in the beginning of 20th century. There are over 100 000 kilometres of water piping underground and part of it is leaking. There are estimates that as much as 20 per cent (80 million cubic meters) of the water is lost in between pump stations and consumers' water tab.
If 20 per cent of water is lost, there are chances that water outside the piping flows into it causing problems with water quality as well. This could generate possibilities for a major water crisis. Difficulty with replacing the pipes is that the piping has been dug below frost line. (Source: Savon Sanomat, 06.07.2011)