Drinking water hygiene

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Drinking water hygiene describes the part of hygiene that affects drinking water . The legal basis is the EU Drinking Water Directive and the respective national laws and drinking water regulations .

Drinking water hygiene deals with all issues relating to the possible impairment of the quality of drinking water within drinking water installations . According to the German Drinking Water Ordinance , the point of transfer of drinking water from the water supply company to the end user is the end of the house connection line (usually the main shut-off valve in the basement of the building). From this point on, the owner or operator of the building installation is responsible for maintaining perfect quality up to the point of use.

Occurrence

Water in drinking water pipes should always flow. If it stagnates over a long period of time, microorganisms can develop in higher concentrations than permitted by the Drinking Water Ordinance. Basically, drinking water is not sterile and can contain different concentrations of microbially usable organic substances. Such substances can also be released into the water by installation components.

Studies have shown that the majority of drinking water installations, especially in the public and commercial sector, do not meet the hygienic and regulatory requirements. This mainly concerns those installations which are not planned, built, operated and maintained according to the generally recognized rules of technology, summarized in VDI / DVGW 6023 .

Possible quality impairments

In a drinking water installation, the drinking water can experience a number of quality impairments. These are differentiated into:

Physical quality impairments

Physical impairment is understood to be discoloration of the drinking water (e.g. due to rust deposits), lime dissolved in the water or the formation of odors. It turns lime is the most common perceived quality impairment, z. B. from calcified coffee machines and limescale deposits on or in sanitary facilities.

Chemical quality impairments

Chemical quality impairments in the building installation can arise when chemical substances occur in increased concentrations. Materials that are in direct contact with water in a drinking water installation can contribute to this. Substances can be released from these materials (e.g. lead pipes ), especially when the drinking water stagnates, and migrate into the drinking water (migration).

Microbiological quality impairments

Drinking water is not sterile and contains microorganisms even if all legal requirements are met. These can be divided into 4 groups depending on their hygienic relevance:

  • Group 1: Natural flora without hygienic relevance, components of every drinking water.
  • Group 3: Strongly increased colony-forming units (CFU), changes in drinking water due to smell, taste and appearance. High hygienic relevance.

Biofilms

Studies have shown that a biofilm can form in drinking water installations . The formation of a biofilm is a complex process that is influenced by various factors - for example the chemical composition and nutrient content of the drinking water, flow velocity, water temperature, and the nature of the wall surfaces. A biofilm in a drinking water installation does not necessarily have to be something bad or harmful, but with unfavorable flow conditions, in addition to a bad smell or taste, hygienic problems can also arise because it can possibly serve as a habitat for pathogenic microorganisms.

Causes of poor drinking water hygiene

The causes are often changes in the use of buildings and the resulting dead lines, resulting stagnation, overdimensioning of the pipeline system, expansions of the pipeline system and the resulting changes in flow conditions, disregard of hygienic regulations during storage, assembly and commissioning of the drinking water installation or a lack of hydraulic balancing .

In particular, growth-promoting temperature conditions in drinking water systems for pathogens are to be listed as one of the main causes.

In summary, this means that hygienic problems usually occur when the generally recognized rules of technology are not adhered to during planning, construction and operation.

Measures in the field of house installation

A sequence of actions is recommended, which is accompanied by research into the causes and appropriate remedial measures. Hygienic safety should be in harmony with energy efficiency and the careful use of natural resources. It is important to ensure the constant flow of water and avoid stagnation. Intelligent, contact-free electronic fittings that are integrated into a water management system are particularly suitable for this. With these fittings, appropriate hygienic flushes can be carried out and thus the necessary circulation of the water can be ensured. In the event of bacterial contamination of the house installation, thermal disinfection or chemical disinfection are recommended . Basically, disinfection measures only solve the hygienic problems in a house installation for a short time and cannot usually replace technical renovation.

Review of the general requirements of the Drinking Water Ordinance in the area of ​​house installation

The general requirements of the Drinking Water Ordinance are regulated in Section 4. In particular, there must be no concern about damage to human health from pathogens. The requirements and parameters set out in Sections 5 to 7a are checked by accredited laboratories in accordance with DIN EN ISO / IEC 17025. Compliance with the generally recognized rules of technology for the extraction, treatment and distribution of drinking water is checked in particular by accredited technical inspection bodies for drinking water hygiene in accordance with DIN EN ISO / IEC 17020.

literature

  • Reinhard Nießner (Ed.), Karl Höll et al .: Water: Use in the cycle - hygiene, analysis and evaluation . 9th edition. de Gruyter, Berlin, New York 2011, ISBN 978-3-11-022677-5

Web links

Web on the left of Germany

Weblinks Austria

Individual evidence

  1. ↑ EU Directive (PDF) (requested on April 6, 2010)
  2. ↑ astandis.at
  3. ↑ a b City of Hamburg (PDF; 167 kB)
  4. ↑ Umweltbundesamt.de
  5. ↑ bibliographical evidence