Tests for the presence of E. coli, coliform bacteria, enterococci, Pseudomonas aeruginosa, Legionella, Clostridium perfringens, and colony count (at 22°C and 36°C). Also tests for the presence of heavy and light metals aluminum, antimony, lead, calcium, cadmium, chromium, iron, potassium, copper, magnesium, manganese, sodium, nickel and zinc; and nitrite, nitrate, phosphorus and sulfate. The hardness of the water is also evaluated.
The Drinking Water Ordinance (TrinkwV 2001) sets maximum values for the existence of substances in drinking water that are hazardous to health, therefore setting clear quality standards. These regulations protect the consumer and require suppliers to carry out regular checks on water quality. However, this obligation only extends to the point at which the water enters the building. Private drinking water systems and tanks are not regulated.
Because contamination of water often occurs after passage to the private tank, many property owners and tennants are interested in testing the quality of their drinking water. In some buildings, water can sit stationary in the pipes for several hours or days at a time. Depending on the material from which the pipes are made, this can cause chemical reactions which release metal ions into the drinking water. The pipes in older buildings may contain copper or even lead, while nickel is sometimes present in taps.
Although some minerals such as sodium, calcium, potassium and magnesium are essential for our health, they can be harmful in high concentrations. Other metals can be toxic even in low concentrations or can accumulate over time within the body. Copper and zinc are involved in the action of metal enzymes or cofactors of enzymes. However, regardless of their function as micronutrients, accumulation often has a harmful effect. Toxification with lead can lead to neurological disorders and anemia. High levels of copper are associated with liver damage and migraines, while zinc and copper adversely affect nutrient metabolism and lead to weakening of immune functions, as well as lower levels of some lipoproteins. Contamination of drinking water with nickel can also trigger allergies. Furthermore, heavy metals can cause growth and development disorders, cancer, and damage to organs or the nervous system, and can also lead to autoimmune diseases (e.g. joint diseases).
To prevent damage to health, the concentration of harmful substances in drinking water should be monitored regularly. Drinking water from well systems may contain various metals and compounds such as sulfate, nitrite, nitrate or phosphate (phosphorus) and pose health risks. Growing urbanisation, industrialisation and agriculture, as well as private and industrial wastewater (e.g. sewage) are significant sources of pollution. Natural geological processes can also pollute groundwater.
Water hardness is measured by the content of calcium and magnesium compounds and can vary greatly from region to region. Soft water is suitable for washing and for all applications where it is heated. It is less suitable for removing soap (e.g. when washing hands) and causes greater foaming in detergents. Hard water promotes calcification of household appliances and increases detergent consumption. It can affect the appearance and taste of food.
Water hardness is expressed in the unit °dH (German hardness).
Soft: <8.4 °dH
Medium: 8.4 - 14.0 °dH
Hard: >14.0 °dH
