Germany is in the relatively comfortable position of having enough water to secure its drinking water supply everywhere. About 70 per cent of its drinking water comes from groundwater. Of the 1,000 groundwater bodies in the country, only about 4 per cent have more water extracted than can be replenished, and that is usually due to mining which requires pumping out groundwater. Excessive extraction of groundwater in coastal regions causes saltwater to seep into groundwater, making it virtually unusable as drinking water. Climate change could increase the pressure for use of groundwater in some regions if – as feared – these regions become drier, or if higher proportions of rain water become surface runoff. Water conservation eases the burden on the water balance and avoids tapping new water resources.
Private households in Germany have achieved a great deal through their economical use of drinking water. The increasing rate of replacement of older appliances with low-flow tap aerators, washing machines and dishwashers will help to further reduce daily water consumption. In terms of European water consumption, Germany is already in the bottom third – and suffers no loss of comfort or quality of life.
However, lower levels of local water consumption can also cause problems to water pipes. The departure of large numbers of the population from rural areas, demographic change and water-saving behaviour can result in water stagnation in the drinking water supply network and thereby compromise drinking water quality. Malodorous sewage gases are formed in some sewage networks because there is too little water flowing through the pipes. However, this is not a problem which households should solve by using more water than necessary: the water utilities or sewage treatment plant operators are the competent bodies to make decisions about when pipes need to be flushed or even if reconstruction of networks might be necessary in the long term.
The environment benefits most when private households use as little energy as possible for hot water preparation. The UBA estimates that the energy required to heat water is an average 12 per cent of the total energy requirement of a household. A full bath (200 litres), for example, costs between €3 and €3.70. Taking a shower is quite a bit cheaper: about 100 litres of water flow through pipes for a 10-minute shower and the heating cost is only half. A water-saving showerhead can cut 50 cents off the cost per shower. Taking a shower once a day means savings of some €180 per person and year.
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