The release of metals from domestic installations to drinking water is investigated in four different water types. The metal release is measured by use of test rigs.

Measurements are carried out in a period of one year in supply water in test systems with simulated use of water. The test rigs are placed at water works with differencies in hardness, alkalinity and neutral salts of the water.

The materials galvanised steel, stainless steel, brass and nickel-chromium plated brass are exposed to drinking water. Each material is tested in form of three different products, which are exposed in duplicate.

Nine times during a year water samples are taken after 12 hours stagnation. Furthermore, after one year of operation time, samples of shorter stagnation time are examined. Thus samples of ½, 2, 4, 8 and 12 hours were taken. Chemical analysis is done for the metals zinc, copper, lead, tin, cadmium, arsenic, chromium, nickel and molybdenum.

The investigation showed that the metal release from common used materials did exceed the drinking water quality demands for the metals zinc, copper, nickel and lead, but not for other metals. The release of zinc, copper and in some degree of lead was strongly dependent of the water composition. The metal release from galvanised steel and copper alloys was increased with increasing hardness. The stainless steel was practically not releasing metals to the drinking water. Other nickel containing materials, such as nickel-chromium plated brass did release too much nickel.

The metal release was not stabilised for all test items after one year of operation.
The investigations are continued.