Munich.Potable water is one of the most frequently tested food products.Nevertheless, consumers are constantly concerned about drinking water safety.But are contaminants, pesticides and nitrates in tap water really a problem?TÜV SÜD has tested water for a host of areas in life and business for many years.In this article, the experts summarise key information about the quality and safety of drinking water.
Consumers expect water that comes out of the tap to be clear and pure and, above all, free from pathogens and microorganisms. As any contamination can quickly affect thousands of people, drinking water quality and safety are regulated by extremely strict standards. Dr Bernd Roesner, Managing Director of TÜV SÜD ELAB GmbH, explains: "Water has always been a natural product, and always will be. Given this, there is bound to be a certain level of contamination, so that a definition of maximum contaminant levels (MCLs) is a reasonable and practice-focused approach."
The applicable German Drinking Water Ordinance (Trinkwasserverordnung, TrinkwV) of 2001, last amended in 2012, includes the MCLs for 53 chemical, physical and microbiological components, among them limits for nitrate (50mg/l) and lead. In 2013, the limit for this heavy metal was reduced from 0.025 mg/l to its present level of 0.010 mg/l. According to the Drinking Water Ordinance of 2001, the zero-tolerance policy applies exclusively to active substances of herbicides and biocides, which are only tolerated up to a limit of detection (e.g. 0.10 µg/l per individual substance). Testing for pathogens is carried out with the help of 'indicator bacteria' as set forth in the Drinking Water Ordinance. The presence of Eschericha coli, for example, almost always indicates recent faecal contamination.
Drinking water in Germany generally offers excellent safety and quality and the results of any samples tested remain below the defined limit values. According to the Federal Environmental Agency, 99 per cent of measurement results meet the quality standards set forth in the Drinking Water Ordinance. The remaining one per cent concerns cases such as measured values for coliform bacteria, which indicate special sources of contamination that are leached into the water supply system by heavy precipitation, structural weaknesses or other causes. The MCLs of individual pesticides are only exceeded in very rare cases. Regarding nitrate, for example, the samples tested have virtually never reached the limit in recent years. While one per cent of the measured values exceeded the MCL in 1999, this value has decreased to almost zero today. Hormone residues and artificial radioactive substances, too, are below the limit of detection.
Legionella in drinking water indicate hygiene problems in the hot water system. Given this, the law requires large-scale installations to be inspected and tested every three years, or even annually in public buildings. In private households, the problems are often caused by sanitary installations themselves, for example by stagnant water at temperatures of between 25 – 45° Celsius. "In this case, the owner or the landlord must act. The most important measure is never to allow the temperature in the hot water system to fall below 55° C in an ill-conceived attempt to save energy", says Dr Roesner. Regional health offices provide information on this issue.
"As potable water is a natural product, any contaminants it contains may accumulate when the water stands in the pipes for over 4 – 5 hours. People who like to drink water straight from the tap should first run the tap to get rid of any stagnant water. Wait till the water feels cool; only then does it offer ideal drinking water quality and safety", advises TÜV SÜD expert Dr Bernd Roesner.
Fresh, pure water is one of the most valuable resources and plays a significant role in the high quality of life in Germany.Every German uses around 120 litres of water every day. Most of this water, i.e. 70 litres, is used for personal hygiene, laundry and flushing the toilet. However, we also need water for cooking and drinking, of course – around 5 litres per day.
In Germany, groundwater pumped up from over 50 m below ground level provides most of our drinking water (around 61 %). Approximately 30 % of our drinking water comes from surface water from reservoirs, lakes and rivers, while well water accounts for only 8 per cent of our water supply. The taste and hardness of our drinking water differ from region to region and are determined by the soil quality of our water reservoirs.