Tap water

Tap water is a collective term for technically in water pipes (pipes ) supplied or located there Knitting water. In common parlance, tap water is usually equated with drinking water. However, types of water are supplied through lines that have no drinking water quality, but be used as process water.

Differentiated management systems

For different purposes, different usage of water lines must be operated in parallel. For example, are installed in some cases three or more line networks where different water quality or temperature is transported in the chemical industry.

Partial two water distribution systems are also present in cities; especially in southern countries where the potable water is scarce, the extinguishing water for the fire hydrants is guided through an independent network of water mains so today. In Central Europe, however, decided the public water supply for a single water pipe in one direction uncertainty in the 19th century, so that they only supplied with potable water. Even in homes and public buildings can waste water, are, for example, used for toilet flushing. This process water for domestic use is now mostly unrelated by the water supplier, but generally obtained from self aufgefangenem rainwater. Because of advances in water treatment technology as well as waste water can be recycled to process water. For such use must be installed within domesticated a second water supply system in addition to the drinking water network.

Quality of drinking water in the form of tap water

The biggest hazard is due to the state of the network and the water pipes used. Where the pipe network is poorly rehabilitated (eg in the UK with water losses of about 30%), also substances from the soil can enter the lines. Until 1990, asbestos -cement pipes have been in Germany for large water pipes in public power supply used.

The Drinking Water Directive regulates that drinking water must be perfect not only at the transfer point into the house, but still on the water faucet. Accordingly, domestic water lines must be repaired by the landlord. Until 1960, lead pipes were used in houses yet, which partly can also still be there today. Lead may cause a range of diseases in humans. In particular, babies and children are at risk from drinking water containing heavy metals, such as through contaminated with copper drinking water. According to drinking water regulations with the limits for lead and copper are at 25 ug Pb / l ( from the year 2013 10 ug / l ) or 2000 ug Cu / L. A discharge from the pipe to the drinking water occurs only rarely. It is important, a layer of limescale on the sufficient inside of the copper pipes. This scale can form only when the water is in the lime - carbonic acid equilibrium. After drinking water regulation, the waterworks are required to verify this. Especially in calcium-poor areas the groundwater can be aggressive. Should show up under a dripping faucet verdigris tracks, so this is a clear sign of insufficient Kalkschutzschicht in the copper pipes. In this case, make sure a professional or the local water company should be asked for advice. From water stagnation occurs when water has come on the way from the source to the tap in the strands of wire longer than 4 hours to a halt. In stagnant water, there is a formation of biofilm due to chemical, physical and microbial processes. Germs that accumulate in the biofilm and multiply, get in the water supply to the consumer. This is the Federal Environmental Agency (UBA ), according to a health risk dar. Therefore stagnation of water should not be used because of possible germs and other loads as drinking water and are made ​​to flow as long as until the noticeably cooler water comes from the public line.

If not sufficient, and constantly taken water from the water pipes, for example, due to demographic changes ( population decline ), there is also a high risk of nucleation. Such problems must counter with rinses and Notentnahmen water utilities. An example of this are some East German municipalities where the water consumption is dropped so significantly in recent years that regular countermeasures by the water utilities were required. In the long run there can be more useful than the maintenance of a centralized system with long lines, a rear or reconstruction of the water system (semi- or decentralized treatment ).

The tap water contaminants, germs can be removed with the use of a nanofiltration plant or osmosis system. These systems are already used longer in the pharmaceutical and food industry; There are also devices for homes and for the semi - centralized use in small settlements available. The tap water in Germany is characterized by the extensive controls almost germ-free and thus can be used for babies and toddlers.

Legionella form in lukewarm water. In Germany, there were problems of this kind, especially in the hot water pipe systems of hospitals and hotels. Legionella cause sometimes fatal Legionnaires' disease.

Other names

Colloquially drinking water from the tap as well as a crane (s) water, referred cranes (s) berger or Kranenburgerstrasse, derived from the West Central German term for crane faucet. In Küppers Dictionary of German colloquial language is this: " Exemplary joke appreciation of water from the crane after the pattern of wine labels or beer brand name. At least since 1900 " Similarly, in French: ". Chateau (de) la pompe ".