Drinking water

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Drinking water from the tap
Drinking water from the glass bottle

Drinking water is water for human needs . Drinking water is the most important food , it cannot be replaced (entry and guiding principle of DIN 2000).

Any water that is used for

or in particular for the following domestic purposes:

  • Body care and cleaning,
  • Cleaning of objects that are intended to come into contact with food (glasses, dishes, cutlery) or
  • Cleaning of objects that are intended to come into contact with the human body and not only temporarily ( clothing , laundry )

Drinking water is fresh water with such a high degree of purity that it - according to the defined quality requirements - is classified as suitable for human consumption, especially for drinking and preparing meals. Drinking water may only contain substances or organisms or contain them in certain quantities for which there are either no limit values ​​or for which the defined limit values ​​are not exceeded or fallen short of. May not be included B. pathogenic microorganisms , minerals should be contained in a minimum concentration, there are no limit values ​​for many chemical pollutants (see pollution ). Requirements of sterility at the extraction point (consumer) enforce permanent or needs-based disinfection measures under certain conditions (extraction location, line length) , which (e.g. by chlorination processes) within the above mentioned. Limit values ​​can cause chemical contamination.

The quality requirements for drinking water in Germany are laid down in DIN 2000 and in the legal basis, the Drinking Water Ordinance (TrinkwV) and in the "General Ordinance for the Supply of Water" (AVBWasserV). The most frequently dissolved minerals in drinking water are the cations calcium (Ca 2+ ), magnesium (Mg 2+ ) and sodium (Na + ) and the anions carbonate (CO 3 2− ), hydrogen carbonate (HCO 3 - ), chloride (Cl - ) and sulfate (SO 4 2− ). The sum of the concentrations of calcium and magnesium is called water hardness .

In seafaring , the drinking water carried is called fresh water .

In Germany, water is not a shortage . Unlike other natural resources, water is not used effectively. Water is only needed and can be contaminated and may then be contaminated with pollutants. The total amount of water on earth in all aggregate states remains the same, only the distribution between the environmental compartments changes. Only an extremely small amount of the water escapes into space as water vapor from the atmosphere .

Water requirement

Queuing for water (March 1920 Kapp Putsch )

The water requirement of humans varies depending on the physical condition, body mass, activity and climate. Humans take water in the form of beverages and food and give it off with urine, feces, sweat and breath. Water is created in the body during the oxidative breakdown of organic nutrients.

The WHO gives an estimate of the drinking water requirement of around two liters per day for a 60 kg adult and one liter for a child weighing 10 kg when there is a “high need”. However, more recent studies indicate that the fluid requirement can also be covered by sufficient consumption of drinks such as juice, milk or coffee and varies greatly from person to person.

Tap water is also used for other purposes, such as washing clothes, flushing toilets, cleaning the body, dishes and apartments. In the last few decades, a consumption of drinking water of 120 to 140 liters per day and inhabitant was expected. The per capita consumption of drinking water in Germany is according to statistics from the Federal Association of Energy and Water Management. V. (BDEW) has continuously decreased since 1990 through conscious use of water.

In other countries, the consumption is partly much higher consumption in Italy is given as 260 liters per day and residents and the desert city of Dubai even one with 500 liters per day and head to the frontrunners and is aiming for the local production of drinking water by desalination of seawater a necessary reduction in consumption.

Drinking water quality

Control of drinking water
Schlund water reservoir in Zollikon , filled with treated lake water from Lake Zurich

In Germany , Austria , Switzerland , France and the Netherlands , drinking water is the most intensely controlled food and is normally unrestricted for consumption .

Problems with the quality of drinking water from groundwater can usually be avoided through the proper designation of protected areas . In some cases, however, the protection in areas with intensive conventional agricultural use is not sufficient. The drinking water obtained from it can be dangerous for infants and small children, in particular through excessive manure fertilization or through old sewage treatment plants and the resulting nitrate entry into the groundwater. In these cases the water supplier has to reduce the nitrate concentration through treatment, deeper wells and cooperation with agriculture.

Water from rivers can contain pollutants from sewage treatment plants or industrial discharges . Pollutants can get into the water during "normal operation" or through accidents. Water suppliers on Germany's major rivers have switched to apron controls and the provision of redundant water treatment technologies. Medicines and other pharmacologically active substances, such as X-ray contrast media or sex hormones , can get into drinking water through the water cycle and lead to systemic risks.

There are higher quality requirements for drinking water in German-speaking countries than for industrially packaged mineral water and table water . It is generally considered to be the best-studied food. In contrast to natural mineral water, drinking water and table water do not have to be "originally pure", so they can be treated and mixed. Drinking water mixed with carbon dioxide - regardless of quality and mineral content - may not be offered as mineral water in restaurants.

In other countries the quality of drinking water is often poor due to inadequate treatment and monitoring. In popular holiday areas such as Spain and Portugal , the quality of the tap water allegedly varies from "suitable for drinking" to "hazardous to health when consumed in large quantities". In China , 60 to 80 percent of the groundwater is heavily polluted and no longer suitable for drinking. In Europe, drinking water is usually suitable for cooking.


In individual cases, increased pollution of the drinking water with pollutants (e.g. arsenic , lead , cadmium , chloride , iron , copper , nitrate , phosphate , uranium , zinc ) can occur at the end user. In March 2013, the ZDF reported on the increased pollution of drinking water with chemical waste such as antibiotics, pesticides and disinfectants. In the Eastern Switzerland 300 were drinking and groundwater samples taken in which it was found that the official peak of the carcinogenic pesticide chlorothalonil in was exceeded over 10% of the samples. Medicinal substances can also be found. Limit values ​​are set (in Germany) by the Drinking Water Ordinance, but there are still no limit values ​​for many pollutants.


Old lead lines in the house installation can be responsible for increased lead content in drinking water. The Stiftung Warentest found in the evaluation of 20,000 drinking water analyzes from the period 1994 to 2004, from taps in households, in five percent of the samples more than 25 micrograms per liter (µg / l) lead. Accordingly, there was an increased risk in eastern German regions, in Schleswig-Holstein and in the greater Hamburg, Bremen, Bonn and Frankfurt areas. The limit value according to the Drinking Water Ordinance is 10 µg / l. Drinking water analyzes can clarify whether your own house installation is affected.

Arsenic and fluoride

Around 300 million people around the world obtain their water from groundwater supplies. However, around 10 percent of the groundwater wells are contaminated with arsenic or fluoride. These trace substances are mostly of natural origin and are washed out of rocks and sediments by the water. In 2008 the Swiss water research institute Eawag presented a new method with which hazard maps for geogenic toxins in groundwater can be created without having to check all wells and groundwater supplies in a region.

In 2016, Eawag made its knowledge freely accessible on the Groundwater Assessment Platform (GAP). This internet portal offers members of the authorities, employees of NGOs and other experts the opportunity to upload their own measurement data and to create risk maps for areas of their own choosing.

Uranium pollution


The consumer organization Foodwatch warned of high uranium concentrations in 2008, for example 39 µg / l uranium was found in Maroldsweisach in the Haßberge district (Bavaria), 33 µg / l in Lobenrot in the Esslingen district and 30.08 µg / l in Reimershagen in the Rostock district (Mecklenburg-Western Pomerania ) determined. A total of 8,200 reported measurements are 150 above 10 µg / l, the limit of the amended Drinking Water Ordinance of 2011. On average, drinking water in Germany contains 0.3 µg / l uranium less than mineral water with an average of 2.8 µg / l. The connection between the increased uranium content in mineral and drinking water and the geology of the groundwater storage rocks was examined nationwide for the first time in 2008. It turned out that increased uranium content is bound to formations such as red sandstone or keuper , which geogenically themselves have increased uranium content. Uranium from phosphate fertilizer has penetrated into the groundwater locally .


As part of a monitoring by the Federal Office of Public Health (FOPH) in the 2000s, the uranium content of drinking water was examined on the basis of 5000 samples in Switzerland. The results were scientifically processed. It was found that higher concentrations were found, especially in the Alpine region, if the water is obtained from groundwater or spring water that is “in contact with uranium-containing rocks and sediments.” The WHO guideline value was reached in 0.3% of the samples of 30 µg / l exceeded. Based on the results of the investigation, the BAG intends to stipulate the limit value of 30 µg / l in the Foreign and Ingredient Ordinance, which would mean that "affected communities have to rehabilitate their water supply within a transitional period of 5 years."

Biological loads

In individual cases, drinking water can be the source of epidemic outbreaks of disease caused by enteral pathogenic viruses. In Finland, for example, a study on drinking water- related norovirus outbreaks was carried out between 1998 and 2003 . In 10 of 18 Norwalk virus outbreaks, the detected subtypes could be detected in the stool samples of the patients, as in the corresponding drinking water samples. These are exceptions that occur in a very limited region and that are immediately remedied through renovation. According to the Federal Health Office and the Federal Environment Agency, well over 99% of the drinking water released in Germany is free of complaints.

Price of drinking water


The price for drinking water in Germany is very different from region to region. The costs for the drinking water supply are mainly determined by the high fixed costs. The lion's share relates to the costs of maintaining and developing the infrastructure. The fixed costs include the costs for extraction, processing (if necessary), storage, conveyance (pumps), transport lines, internal supply lines (connection density, i.e. consumers per km of supply line) and water meters, which are also incurred without consumption . These costs are also influenced by the geological and topographical conditions, the settlement structure and the rate of rehabilitation of the supply lines. These fixed costs are usually allocated to consumption costs. Drinking water in Germany costs around 1.69 euros per cubic meter on average. The proportion of fixed costs in the water supply averages between 75% and 85% of the total costs, so saving water for the entire group of connected consumers can hardly lead to lower costs for the consumer. Wastewater charges are mostly assessed 1: 1 based on the drinking water consumption of the private household, for which about two to four euros per cubic meter are added.

In 2007 and 2011 studies in Essen found that the price was around 340% higher than in Augsburg. In Essen, water is twice as expensive as in neighboring Bochum . Different requirements (raw water origin, raw water quality, treatment costs, topography, infrastructure costs) of the water suppliers are named as the cause for the price differences.


The drinking water price is primarily determined by the type of extraction and transport, which varies from place to place. The water corporations and the responsible municipalities also determine the extent to which future investments or their amortization are to be taken into account in the price. As a result, each water corporation or municipality defines the drinking water prices for the respective supply areas. In St. Gallen , which draws lake water from Lake Constance and has to be pumped up accordingly, the cubic meter costs CHF 2.66 as of 2017, while the groundwater and spring water in Altdorf cost CHF 0.40. There are also fees for the connection, for the water meter and for the waste water.

The water costs for the 300 most populous municipalities can be viewed on the website of the Federal Price Supervisor .

Hygienic aspects

The articles drinking water hygiene , drinking water # hygienic aspects , drinking water # hygienic requirements , hot water # hygienic requirements , legionella and VDI / DVGW 6023 overlap thematically. Help me to better differentiate or merge the articles (→  instructions ) . To do this, take part in the relevant redundancy discussion . Please remove this module only after the redundancy has been completely processed and do not forget to include the relevant entry on the redundancy discussion page{{ Done | 1 = ~~~~}}to mark. Kai Kemmann ( discussion ) - Improving instead of deleting - 04:57, 11 Feb 2020 (CET)

A safe and hygienic water supply is a decisive contribution to health and disease prevention . According to the Drinking Water Ordinance (TrinkwV), drinking water in Germany must meet the following requirements:

  • colorless, odorless
  • free from pathogens
  • not harmful to health
  • neutral in taste and cool
  • dissolved mineral substances in certain concentration ranges

In Central Europe, drinking water is mostly obtained from groundwater through wells , more rarely artesian wells or directly from springs . Also surface water from Talsperrseen , lakes or rivers is used. The water is either taken directly from the body of water or processed into drinking water as bank filtrate from wells near the body of water. In individual cases, mostly outside of Europe, it is obtained directly from river water. In industrialized countries, transport to the consumer is usually carried out by a water distribution system made up of pumps, pipes and tanks. In many developing and emerging countries and sometimes in emergencies in industrialized countries, it is distributed by tank trucks or containers such as bottles, barrels and plastic bags.

VDI 6023 is an important guideline for drinking water systems in Germany. It deals with the correct planning, construction, operation and repair of drinking water systems in buildings and on properties. Since drinking water does not flow in the supply lines in front of the taps in the meantime, more microorganisms can develop in the water lines in the event of a prolonged stagnation period, in higher concentrations than permitted by the Drinking Water Ordinance. Water that has been left in gunmetal fittings or pipes for a long time can have a higher content of dissolved metals such as lead.

Drinking water treatment with ultrafiltration to remove germs and cloudiness

Organization of the drinking water supply

Germany, Austria and Switzerland are so rich in water due to their geographical location and precipitation situation that the water demand can mostly be met locally or regionally. In many cases, however, regional and supraregional land supplies ( e.g. Gelsenwasser or Suez Environnement ) have been set up in Central Europe . The construction, maintenance and operation of water supply systems is carried out in most federal states by municipalities , companies , water cooperatives , water associations and privately organized companies. Unlike in other European countries, such as the Netherlands, where concentration processes have been accelerated by the state, in Germany the public water supply has so far been predominantly communal and organized according to the local occurrences.

Only a few of the German utility companies operate nationally and even less internationally. The major French utilities are actively involved in the privatization of water supplies around the world.

Drinking water production

Approx. 25% of the world population are water from Karst - aquifers instructed. The Institute for Applied Geosciences at the Karlsruhe Institute of Technology (KIT) published as a project of IAH Karst Commission ( International Association of Hydrogeologists ) in September 2017 at the 44th annual congress of the IAH in Dubrovnik in addition to the 2000 published groundwater - World Map (WHYMAP, World-wide Hydrogeological Mapping and Assessment Program ) together with the Federal Institute for Geosciences and Natural Resources (BGR) and UNESCO a " World Karst Aquifer Map ".

Drinking water dispenser in Überlingen

Extraction from wells

In the case of wells , a distinction is generally made between two different types, namely the shaft well and the drilled well . With a shaft well, near-surface groundwater is usually extracted between 8 and 10 meters below the ground. The groundwater is drawn down to a depth of 400 meters with a borehole.

The depth of the well depends on the position and thickness of the water-bearing layers. Each well has a maximum conveying capacity, which depends on the size of the aquifer, its permeability and the corresponding well construction , such as the well and filter pipe diameter and the length of the well filter sections. Underwater pumps convey the water for treatment or, if the quality is useful, directly into the drinking water supply network. The number of wells was based on the quantity requirements of consumers and the water balance ; it is limited by the authorities for each water extraction area, so that only the amount flowing in from one area is taken from each area.

Since manholes do not reach great depths, the quality of the water can be impaired by the proximity to the earth's surface. In the case of a drilling well (deep well), a delivery pipe is hung that has slots in the water-bearing area. In order to hold back sand, earth and other coarse suspended particles, a filter gravel packing is placed around the pipe. Above the ground, the delivery pipe ends in the well room, in which the necessary electrical and hydraulic equipment is housed.

With increasing depth, the temperature of the water from deep wells ( geothermal depth level ) increases, namely by an average of 3 ° C per 100 m, if there is no geothermal anomaly (as in the Upper Rhine Rift) that causes a greater rise. With an assumed annual average temperature on the earth's surface of 10 ° C, the water temperature at a depth of 100 m is approx. 13 ° C.

Extraction from sources

Spring water is emerging groundwater. Its suitability as drinking water depends on whether surface water comes to light or water from deeper layers. If the source is mainly fed by near-surface water (surface water), there is a risk that environmental pollutants, germs, bacteria, nitrate or mineral oils will get into the spring water. Therefore, every source that is used for drinking water production must be protected by a correspondingly large drinking water protection zone.

The following source types are relevant for drinking water production:

  • Layer source : The groundwater emerges when the water-bearing layer cuts the surface of the earth.
  • Damming source : groundwater accumulates under a water-impermeable layer and, if this layer breaks through, it comes to the surface of the earth.
  • Overflow source: The groundwater is pressed to the surface of the earth by hydraulic pressure in the groundwater layer.

Extraction from surface waters

Surface water is pumped from lakes or rivers to obtain drinking water. It mostly has to be processed. Well-known examples are the supraregional Lake Constance water supply , the water supply of the city of Zurich or the numerous water supply systems that take raw water from reservoirs.

Sea water

In arid coastal countries, drinking water is mostly obtained through energy-intensive seawater desalination plants , usually through reverse osmosis . The energy consumption is 4 to 9 kilowatt hours per cubic meter of water. In the case of a distillation at atmospheric pressure without energy recovery, it would be far higher at 700 kilowatt hours.

Drinking water supply for the military through a water bag ( Diekirch Military Museum )

Drinking water treatment

Drinking water treatment is the production of drinking water by cleaning ground or surface water using chemical and physical treatment processes and setting certain parameters (pH value, ion concentration) to make it suitable for use as drinking water. The technology required for the treatment is installed in waterworks . Drinking water in individual households that are not connected to a waterworks or whose tap water is not suitable as drinking water is often treated with smaller devices. The type of water treatment depends in both cases on the quality of the raw water and depends on the substances contained in the raw water and to be removed. In particular, the processes of filtering , iron removal and manganese removal , deacidification , degassing , decarbonisation and disinfection are frequently used.

Suspended solids in the water can aggregate into larger particles through flocculation and be removed from the water through filtration with gravel filters . Corrosive carbon dioxide is blown out by ventilation . By oxidation of dissolved iron (II) - ions to form insoluble iron (III) oxide hydrate converted and dissolved manganese (II) ions into insoluble manganese (IV) compounds. The iron oxidation is partly abiotic , partly biotic . The biotic oxidation is caused by bacteria of the genus Gallionella , mainly G. ferruginea . Manganese oxidation takes place more slowly than iron oxidation and is also partly biotic (specific manganese-oxidizing bacteria). Most of the precipitated iron (III) oxide hydrate is removed in a first filtration stage through a gravel filter (iron removal). There are large amounts of Gallionella ferruginea in these filters . The precipitated manganese (IV) compounds are removed in the lower third of the combined iron and manganese removal filter or in a second filtration stage with gravel filters.

Dissolved organic substances are removed through adsorption on activated carbon and biological degradation in slow filters or through soil passage (seepage).

Near-surface groundwater, such as bank filtrates from rivers, are often treated with ozone . This treatment oxidizes organic substances as well as iron and manganese compounds. While iron is precipitated as an oxide hydrate, manganese oxidizes to permanganate. Two-layer filters or double-layer filters are therefore used for the subsequent filtration of water treated in this way with ozone. In the case of the 2-layer filters, the lower layer consists of gravel, in which undissolved and precipitated components are filtered off, provided that these have not already been absorbed by the upper first layer. The 2nd upper layer consists of coarse-grained activated carbon. This layer adsorbs the partially oxidized organic substances and reduces the permanganate to precipitated manganese (IV) compounds, which can be filtered off. In the case of double-deck filters, the spatial separation means that the specifically heavier filter material such as activated coke or gravel can be placed in the upper part and the lighter activated carbon in the lower part. With the double-deck filters, this prevents the activated carbon from becoming silted up more quickly due to the filtration of solids. When the filter is backwashed (rinsing out the deposits), the specifically lighter activated carbon is repeatedly deposited as the top filter layer.

If pathogenic bacteria and viruses are to be expected, disinfection is necessary. This can be done by ultrafiltration in the waterworks or by ozonation . After filtration, transport chlorination can be carried out by adding chlorine, chlorine dioxide or sodium hypochlorite ( chlorination ) in order to prevent recontamination in the network.

For many purposes, water with a high carbonate hardness has to be partially softened by decarbonisation. In the case of filtered water, depending on the pore strength used, substances such as minerals must be added in order to achieve sufficient osmolarity . Systems based on the principle of reverse osmosis are used to obtain drinking water from raw water that is rich in salt. Groundwater is usually of such good quality that it can be turned into drinking water without flocculation and disinfection. Further processes of drinking water treatment are softening and partial desalination with the help of ion exchangers or membrane technology such as osmosis and dialysis . A portion of uranium can be removed from drinking water by using ion exchangers; there are processes on the market.

Legal issues

In Germany and Austria, the quality of drinking water is regulated by the Drinking Water Ordinance (TrinkwV). With amendments to these ordinances, the EC directive "On the quality of water for human consumption" (98/83 / EC) was implemented in national law. In Austria, the relevant amendment to the Drinking Water Ordinance was announced on August 21, 2001 and in Germany it came into force on January 1, 2003. Compliance with the drinking water ordinance by the water supplier is monitored by the health authorities.

In Germany, the DVGW e.V. is responsible for the standardization and approval of processes and materials in the field of drinking water . V. responsible. The responsibilities include all aspects of drinking water treatment, storage and distribution and have a binding character, similar to a DIN standard.

The WHO has created a standard for drinking water, which is based on the EU directive and the TrinkwV. In these ordinances, among other things, the substances to be tested in drinking water and the associated permissible limit values ​​as well as the frequency of the measurements to be carried out are specified. The limit values ​​that allow water to be released as drinking water are based on the idea of promoting health ( precautionary principle ). One problem is that the analyzes do not capture all conceivable or known loads. 1500 substances of anthropogenic origin can easily be found in water. The WHO requires 200 substances to be tested because of their known health effects. According to the German Drinking Water Ordinance, a total of only 33 substances that may be in the water with associated limit values ​​are named that would have to be checked in a complete drinking water analysis. However, an indicator principle has been implemented so that the probability of exposure to related substances can be assessed in groups, for example Escherichia coli ( E. coli ) stands for all faecal germs and the sum of mercury, lead and cadmium stands for all heavy metals .

The Escherichia coli content is cultured in the laboratory; the target value for drinking water is 0 CFU in 100 ml (CFU = colony-forming units). Alternatively, the measurement can be based on the metabolism of the bacteria, which enables a determination within 30 minutes.

The German water supply companies deliver good to very good quality. This is the conclusion of the current second report by the Federal Ministry of Health (BMG) and the Federal Environment Agency (UBA) on the “Quality of Water for Human Consumption”, which looks at the years 2005 to 2007. Accordingly, over 99% of the systems comply with the strict legal requirements.

An evaluation of 30,000 water data from AQA (Aqua Quality Austria) showed that 21.6% of the water sample exceeded at least one limit value for undesirable ingredients. Lead and nickel from pipes and fittings are the main problem; AGA has therefore repeatedly appealed to the manufacturing industry to develop reliable solutions. In Austria, the limit value for lead was reduced from 25 μg / l lead to 10 μg / l in 2013. Chromium, copper and nitrate are other problem substances that arise. In domestic wells, especially those that are only used seasonally or sporadically, the drinking water was rated as "not fit for human consumption" in 40% of cases due to a lack of hygiene. Heavy rain or floods in particular can have a negative impact.

On July 2, 2019, the Austrian National Council enshrined a ban on the privatization of drinking water in the federal constitution.

Developing countries

A source of water in Tanzania

Around three billion people have no access to clean drinking water. Inadequate supply of clean drinking water is the leading cause of illness and death in developing countries , especially high child mortality rates. Numerous development projects are devoted to solving this problem, but none of these projects will reach two to three billion people. A significant obstacle is the link between funding from EU development aid and private water supply companies. Self-help through municipal and cooperative solutions remains without funding. A simple emergency water treatment for crisis areas or slums was developed in Switzerland with the SODIS project, this procedure is recommended by the WHO for the disinfection of drinking water at household level.

Environmental aspects

Drinking water from the tap causes up to a thousand times less pollution than mineral water , as was determined in a comparative study ( life cycle assessment ) for Switzerland. The infrastructure for treatment and distribution as well as the energy consumption for pumping are negative aspects for the ecological balance of drinking water. Energy is used to obtain drinking water. In this respect, avoiding the waste of drinking water belongs to environmental protection. If drinking water is to be substituted by service water (e.g. rainwater, gray water), certain precautions must be taken to rule out any risk to the drinking water and the users. Corresponding requirements for the planning, construction and operation of service water systems are described in the VDI 2070 guideline.

Drinking water installations

A drinking water installation (house installation) is generally the part of the drinking water network from the main water meter in a building to the extraction fittings . Depending on the context, the system components can be counted from the water entry into a building or from the property line to the house installation. As a rule, however, the pipe system up to the water meter belongs to the water supply company .

For the identification of cold, warm and circulation pipes, see water pipe # marking .

Hygienic requirements

The articles drinking water hygiene , drinking water # hygienic aspects , drinking water # hygienic requirements , hot water # hygienic requirements , legionella and VDI / DVGW 6023 overlap thematically. Help me to better differentiate or merge the articles (→  instructions ) . To do this, take part in the relevant redundancy discussion . Please remove this module only after the redundancy has been completely processed and do not forget to include the relevant entry on the redundancy discussion page{{ Done | 1 = ~~~~}}to mark. Kai Kemmann ( discussion ) - Improving instead of deleting - 04:57, 11 Feb 2020 (CET)

Drinking water is usually not sterile and may contain a certain concentration of bacteria. If the water remains in the pipes for a long period of time ( stagnation ), there may be an increased multiplication of harmful germs such as legionella . This is especially true if the water warms up above the temperature of 8 to 10 ° C at which it usually reaches the house from the municipal drinking water supply. To avoid stagnation, the guideline VDI / DVGW 6023 “Hygiene in drinking water installations; Requirements for planning, execution, operation and maintenance "recommended to completely replace the water in drinking water installations at least once every 72 hours. Operators and users of drinking water installations should therefore ensure that every drinking water tap (hand basin, toilet, shower) is flushed regularly if they are absent for a longer period of time. This can be organized organisationally (by manually opening the tapping points) or technically (automatic flushing valves). According to the Drinking Water Ordinance, the “entrepreneur and other owner” of the drinking water installation is liable for damage caused by improper use of drinking water installations. A risk analysis is to be arranged by him.

In drinking water networks that are built and operated in accordance with the recognized rules of technology such as DIN 1988, stagnating conditions have only a minor influence on the increase in the number of colonies.

Approval mark for drinking water installations

According to the German Drinking Water Ordinance (TrinkwV 2001) and the “Ordinance on General Conditions for the Supply of Water” (AVB-WasserV), only products for drinking water installations that have a DVGW or DIN-DVGW certification mark may be used.

Operating temperatures

DIN EN 806-2 states that, for hygienic reasons, 30 seconds after opening a tap, the temperature of the cold water should not exceed 25 ° C and that of the warm water should not fall below 60 ° C, unless local guidelines prevent this. In addition, it should be possible to heat the hot water to 70 ° C at each tap in order to thermally disinfect pipes and fittings. This is primarily intended to prevent the multiplication of Legionella bacteria.

The national supplementary standard DIN 1988-200 states similar values, but explicitly requires them. Accordingly, 30 seconds after opening a tap for cold water, the temperature must not exceed 25 ° C and the hot water temperature must reach at least 55 ° C. In technical centers and installation shafts, the temperature of the cold water should not exceed 25 ° C if possible. The standard also requires marked (and, if necessary, disinfectable) sampling points in order to be able to check the proper quality of the drinking water.

To protect against scalding , however, depending on the user group, the tap water should come out of the tapping point in public buildings with a maximum of 38 - 45 ° C. Water above 60 ° C can cause scalds within seconds, whereas this only takes about 2 minutes with water at 50 ° C.

Barrier areas

According to DIN EN 806-2, all consumption and distribution lines must be lockable and drainable. Every part of the building with its own water supply must be lockable. The drinking water pipes to each floor and to each apartment must also be individually lockable. The shut-off valves should be placed in an easily accessible location near the entry point. In particular, all lines that branch off from the main line and supply several usage units together should be blocked off. In addition, every washing machine connection, cistern, water tank, water heater and every other device must have its own shut-off valve.

DIN 1988-200 requires at least one shut-off valve with a drain cock after the water meter and other shut-off options if this is necessary for maintenance of the pipe system. Sufficient drainage equipment (waste water connection) must be available at every tap and device drain. Shut-off, drainage, safety and safety fittings must be easy to use and accessible.

Cold water supply lines

According to DIN 1998-200, the supply lines to individual tapping fittings should be made as short as possible and contain a maximum volume of 3 l.

Lines that are rarely used or at risk of frost, such as those to ancillary buildings, garden and courtyard areas, must have a shut-off and drainage valve directly at the branch from the main line and should be marked.


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  • Thomas Kluge , Jens Libbe (ed.): Transformation of network- bound infrastructure. Strategies for municipalities using the example of water. Berlin 2006, ISBN 978-3-88118-411-3 (= Difu contributions to urban research , volume 45).
  • Thoralf Schlüter: Drinking water supply in international comparison. Supply situation, water management structures and drinking water prices . Diplomica, Hamburg 2006, ISBN 3-8324-9339-5 .
  • Hans-Jürgen Leist: Water supply in Germany - criticism and possible solutions. Oekom, Munich 2007. ISBN 978-3-86581-078-6 .
  • Jens Libbe and Ulrich Scheele: Spatial aspects of quality and supply standards in the German water industry. In: Federal Office for Building and Regional Planning (ed.): Infrastructure and services of general interest in the area . Information on spatial development 1/2 2008, pp. 101–112, ISSN  0303-2493 .
  • Matthias Nast: Drinking water - our most important food. Advice to the Foundation for Consumer Protection . Ott, Bern 2010, ISBN 978-3-7225-0118-5 .
  • Matthias Maier, Volker Steck, Matthias Maier (eds.): Drinking water: the basis of life in a young city , published by the Karlsruhe City Archives and the Karlsruhe Public Works, Info-Verlag, Karlsruhe 2015, ISBN 978-3-88190-830-6 (= houses - and Building History , Volume 13).

Web links

Wiktionary: Drinking water  - explanations of meanings, word origins, synonyms, translations
Commons : Drinking Water  - Collection of pictures, videos and audio files

Individual evidence

  1. twin no. 9, DVGW German Gas and Water Association, Bonn.
  2. The EU and WHO guidelines for drinking water are based in part on different parameters and are in the form of recommendations, see comparison of drinking water standards of the WHO, the EU and Germany .
  3. http://www.who.int/mediacentre/factsheets/fs256/en/ ( Memento from April 4, 2004 in the Internet Archive )
  4. Telepolis: Should we drink 2.5 liters of water a day?
  5. ^ Spiegel Online: Myths that even medical professionals believe in
  6. Dubai wants to reduce water consumption , accessed on March 6, 2011.
  7. Abu Dhabi: Water consumption in the UAE, as of 2006 ( Memento from November 12, 2011 in the Internet Archive )
  8. Der Spiegel : Eco-madness mineral water . No. 39 of September 22, 2014, page 44
  9. Meike von Lojewski Drinking water in Spain - how enjoyable is it?
  10. Axel Dorloff: Water in China - massive pollution, especially in the groundwater. In: deutschlandfunk.de. May 19, 2016, accessed January 6, 2020 .
  11. Overview: Pollutants in drinking water
  12. Video today: Chemical waste in drinking water (March 16, 2013, 7:09 p.m., 2:00 min.)  In the ZDFmediathek , accessed on February 11, 2014. (offline)
  13. Angelique Beldner: Ban comes in autumn - Carcinogenic pesticide in Swiss drinking water. In: srf.ch . June 20, 2019, accessed June 22, 2019 .
  14. ^ Fritz H. Frimmel: healing loads. Springer-Verlag, 2006, ISBN 978-3-540-33638-9 , p. 207 ( limited preview in Google book search).
  15. "Lead in drinking water" environmental card from Stiftung Warentest
  16. Manouchehr Amini, Kim Mueller, Karim C. Abbaspour, Thomas Rosenberg, Majid Afyuni, Klaus N. Møller, Mamadou Sarr, C. Annette Johnson: Statistical Modeling of Global Geogenic Fluoride Contamination in Groundwaters. In: Environmental Science & Technology . 42, 2008, pp. 3662-3668, doi: 10.1021 / es071958y .
  17. Manouchehr Amini, Karim C. Abbaspour, Michael Berg, Lenny Winkel, Stephan J. Hug, Eduard Hoehn, Hong Yang, C. Annette Johnson: Statistical Modeling of Global Geogenic Arsenic Contamination in Groundwater. In: Environmental Science & Technology. 42, 2008, pp. 3669-3675, doi: 10.1021 / es702859e .
  18. L. Rodriguez-Lado, G. Sun, M. Berg, Q. Zhang, H. Xue, Q. Zheng, CA Johnson: Groundwater Arsenic Contamination Throughout China. In: Science . 341, 2013, pp. 866–868, doi: 10.1126 / science.1237484 .
  19. Groundwater Assessment Platform (GAP)
  20. Focus: Uranium in drinking water alerts authorities , August 5, 2008
  21. ^ Uranium in drinking and mineral water. In: Health Department Bremen. Retrieved April 18, 2016 .
  22. A contribution to the occurrence and origin of uranium in German mineral and tap water
  23. ^ E. Stalder, A. Blanc, M. Haldimann, V. Dudler: Occurrence of uranium in Swiss drinking water . In: Chemosphere . tape 86 , no. 6 , February 2012, ISSN  0045-6535 , p. 672–679 , doi : 10.1016 / j.chemosphere.2011.11.022 (English).
  24. ^ Occurrence of uranium in Swiss drinking water . Food safety. In: Federal Office of Public Health (Ed.): BAG Bulletin . No. 12/12 , March 19, 2012, ISSN  1420-4266 , p. 206–207 ( archive.org [PDF; accessed June 8, 2017]).
  25. Leena Maunula, Ilkka T. Miettinen, Carl-Henrik von Bonsdorff: Norovirus Outbreaks from Drinking Water. In: Emerging Infectious Diseases. 11, 2005, pp. 1716-1721, doi: 10.3201 / eid1111.050487 , PMC 3367355 (free full text).
  26. VKU FAQ ( Memento from May 5, 2014 in the Internet Archive ).
  27. Differences in the price of water - Augsburg cheap, food expensive .
  28. Robert Bösiger: Water costs, but not the same everywhere. In: look. Retrieved June 8, 2017 . (According to Max Maurer, Head of Urban Water Management, Eawag Water Research Institute)
  29. St.Gallen drinking water - the best thirst quencher. City of St. Gallen, accessed on June 8, 2017 .
  30. water supply. (No longer available online.) Altdorf parish, archived from the original on February 11, 2006 ; accessed on June 8, 2017 .
  31. Price Supervisor's Fee Comparison Website. Federal Department of Economic Affairs, Education and Research , accessed on June 8, 2017 .
  32. Merk, Markus (AGW): KIT - AGW: WOKAM. September 10, 2017, accessed December 8, 2017 (German).
  33. ^ Nico Goldscheider, Neven Kresic: Karst hydrogeology home. Retrieved December 8, 2017 .
  34. BGR - WHYMAP. Retrieved December 8, 2017 .
  35. BGR - WHYMAP - BGR, KIT, IAH, and UNESCO presented new World Karst Aquifer Map. Retrieved December 8, 2017 .
  36. Water quality - explanation of individual parameters , accessed on November 21, 2014.
  37. Dirk Asendorpf : It depends on the pore . Zeit Online February 13, 2009, accessed November 21, 2014.
  38. Drinking water: From the pipe instead of the plastic bottle , accessed on November 21, 2014.
  39. Ed. DVGW e. V .: Water transport and distribution . Oldenbourg Industrieverlag GmbH., Munich 1999, ISBN 3-486-26219-X , pp. 3-5.
  40. Every fifth water sample exceeds the limit value. on help-ORF.at March 19, 2015
  41. Drinking water is now protected by the constitution. Retrieved July 2, 2019 .
  42. N. Jungbluth: Comparison of the environmental pollution of tap water and mineral water . In: Gas, Wasser, Abwasser Vol. 2006 (3): 215-219. ( Memento of November 28, 2009 in the Internet Archive ) (PDF; 1.3 MB)
  43. VDI 2070
  44. DVGW e. V. (Ed.): DVGW-Information Wasser No. 81 Planning, construction and operation of water distribution systems from the point of view of the assessment and avoidance of germs . Wirtschafts- und Verlagsgesellschaft Gas und Wasser mbH, 2013, ISSN  0176-3504 .
  45. Tino Reinhard: Meaning and content of DIN EN 1717 - system standard regulates drinking water protection across Europe , IKZ Haustechnik, issue 13/2006, p. 32ff.
  46. Overview of the planning of drinking water installations and the regulations according to DIN EN 806 and DIN 1988-200 in the publication Sanitärtechnisches Symposium 2010 of the Central Association of Sanitary, Heating, Air Conditioning
  47. DIN EN 806-2 requires a maximum temperature of 45 ° C for public buildings. In nursing homes and facilities for children, the temperature should generally not exceed 43 ° C and in showers 38 ° C. VDI 3818 generally recommends 40 ° C for public baths and toilets.
  48. FAQ Thermostatic mixing valves - Why is it important to have a thermostatic mixing valve? ( Memento of September 20, 2018 in the Internet Archive ), ESBE AB, Sweden