Mains diagram for drinking water installation - what needs to be taken into account?

This article explains in detail what the piping scheme in the drinking water installation means and what must be paid particular attention to.

Line scheme

The laying of drinking water pipes in the house must be carefully planned. This is necessary if only to ensure that all areas are supplied with cables as efficiently as possible.

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First, a line diagram is created for the planning. This is sometimes called "interpretation " in technical jargon. A floor plan of the building and an additional sectional plan are required for the design.

At the beginning of the planning, all extraction fittings are drawn in and connected using the best possible line diagram.


The hydraulic aspects are particularly important when planning the drinking water installation in the house. Pressures, flow rates and pipe diameters must be calculated in the line diagram. Then the total flow rates are calculated.

The sections also have to be calculated, then the most unfavorable flow paths. The calculation of the peak flow and the calculation of the circulation line are then carried out.

DIN 1988, Part 300, serves as the basis for calculating the lines in the line diagram in this area.

Only the calculation results in an implementable scheme of the pipe run with the appropriate pipe thicknesses, fittings and connections.

Hygienic aspects

In addition to the hydraulic aspects, hygienic aspects are also becoming increasingly important. The water pipes must be designed in such a way that there is nowhere too large amounts of water remaining, as this can strongly promote the growth of bacteria.

Basically, all lines should be dimensioned in such a way that the water does not last for a long time. This is not always easy to achieve - the bigger the building, the more difficult this aspect is to implement. In many cases, downtimes can hardly be avoided.

Even with an existing or planned rain harvesting system, the transfer areas are often problematic in terms of hygiene. The separation into a service water and a drinking water circuit should also be accomplished with as little installation effort as possible.

Tips & Tricks The design may only be carried out by a competent specialist company. The planning of drinking water installations is a very complex special task. The executor is also liable for proven planning errors.