The Institut Kirchhoff’s qualified and regularly trained sampling team takes care of the professional sampling. However, sampling as an integral part of an analysis procedure must always be tailored to the objective of the inspections. In partnership with you, we work out a sampling plan; even for larger numbers of taps/hydrants. As well as the legally required monitoring as set out in the Drinking Water Ordinance, the different ways the water is used or supplied also influence the inspection objectives.
Samples can be taken to serve different purposes. For example, to determine quality of drinking water:
- In the distribution network, which is the responsibility of the water supplier (water works),
- In the drinking water installation (in the home or building);
- At an extraction point (tap).
Different sampling methods for analysing different parameters:
- Single sample: A one-off sample (microbiological parameters),
- Random sample: Randomly selected time and place; removal of 1 litre without prior flushing or similar (metals)
- Composite sample: A sample that is continuously taken over a determined period of time, or a sample of multiple samples that were taken and mixed, either continuously or intermittently, over a determined period of time
- Qualified sample: A composite sample of at least five samples that were taken and mixed over a period of no more than two hours at a rate of no less than every two minutes.
Sampling for analysing lead, copper and nickel:
In order to receive information about breaches of the threshold, first of all a basic random sample is taken. Because, as stipulated by the Drinking Water Ordinance, the threshold is based on the so-called weekly average, which is determined by staggered stagnation sampling, this method is well suited when initial findings are striking. Thanks to taking three samples, and the defined stagnation time, the extent of the threshold breach is determined and the origin of the metal is isolated.
If required, we can supply you with appropriate sampling vessels free of charge. We would be pleased to advise you.