The water supply (the amount of groundwater and surface water that is theoretically available per year through precipitation minus evaporation and inflow) is around 188 billion cubic meters per year in Germany - this makes Germany one of the water-rich countries on earth. Less than 20 percent of this is actually required by agriculture, thermal power plants, mining and trade, as well as the public water supply. Almost the entire population (99 percent) is supplied with fresh drinking water by over 6,000 public water supply companies. Around 70 percent of this drinking water comes from groundwater and spring water and around 30 percent from surface water, for example from lakes, dams or bank filtrates. But despite the very high initial and supply quality, the drinking water that runs out of the tap in the household does not always meet the requirements of the Drinking Water Ordinance.
Quality that does not go down well with the consumer
Drinking water is one of the most strictly controlled foods in Germany. The Drinking Water Ordinance specifies exactly how much of what can be contained in the water. From the house connection onwards, however, every owner is responsible for the water quality. As part of a cooperation between the Stuttgart Fraunhofer Institute for Interfacial Engineering and Bioprocess Engineering IGB and the Austrian AQA GmbH, results from national drinking water samples ("water checks") have now been analyzed and evaluated. The analysis shows that the quality that consumers receive in the water glass is not always what it should be.
The problem areas: heavy metals and nitrate
Every sixth submitted and evaluated water sample contained heavy metals such as nickel, lead, copper, iron or manganese in concentrations above the permitted values. These elements are mainly washed out of house pipes and fittings into the drinking water when the material reacts with the water. Since copper or galvanized pipes are often laid, sometimes still lead pipes or galvanized pipes with cadmium content, traces of these heavy metals can dissolve and have a significant impact on the quality of the drinking water and the taste. For example, the limit value for nickel was exceeded in almost every tenth of the samples examined at Fraunhofer IGB.
The nitrate concentrations in the area of the house wells also show that the permitted limit values are drastically exceeded. Intensive agricultural land and land use can pollute groundwater resources with nitrates, among other things. The analyzed water samples from the house wells showed increased nitrate levels at 15.9 percent. "It is important to ensure compliance with the nitrate limit values in drinking water, especially with baby food," says graduate engineer Stephan Bruck, managing director of AQA, explaining this situation.
Test brings security
AQA and the Fraunhofer IGB offer an independent, comprehensive and reliable water check for private households. The consumer takes the water sample himself by means of a test kit following precise instructions and sends the sample to the Fraunhofer IGB. "We use the most modern methods to analyze the water samples sent in for 24 relevant chemical-physical parameters, for example for metals, trace elements and salts. We also assess odor and cloudiness and determine the water hardness," says food chemist Gabriele Beck-Schwadorf, Head of Analytics at Fraunhofer IGB . In the future, the test is to be supplemented by bacteriological tests for possible bacterial contamination of the water samples.
The WasserCheck is subject to the highest quality requirements and includes easy-to-understand instructions for taking samples. The result is compared with the limit values from the Drinking Water Ordinance and any excess values are shown separately. This means that every household can have the quality of their drinking water checked at any time - reliably and safely. If excessive heavy metal values are found for domestic drinking water, a remedy can often be found by letting the water run for a while.