In Germany, drinking water is considered a reliably controlled foodstuff. However, to reliably maintain drinking water quality in projects, one must think beyond the point of connection to the property. This is because water that arrives at the handover point in very good quality subsequently passes through a technical system comprising pipes, fittings, insulation, circulation, and usage patterns. Each of these elements can influence water quality.
Drinking water quality serves to protect the health and safety of consumers. To ensure this remains the case, it is a fundamental issue of planning, interfaces, and building systems.
What makes good water?
Good drinking water is clear, cool, colourless and has no noticeable odour or taste. This is also how the Federal Environment Ministry describes it in its information on drinking water quality. At the same time, this sensory assessment is not sufficient for technical projects. For planning and operation, microbiological, chemical, and physical parameters are what count.
Microbiological contamination can pose short-term health risks. Chemical inputs or reactions between water and materials, on the other hand, often only become apparent over longer periods of time. The technical measures required therefore differ accordingly: temperature control, flow rates, material compatibility, prevention of stagnation, and suitable sampling points all interplay.
For planning, this means that water quality must be described, documented, and ensured throughout the installation’s lifecycle. Proper drinking water hygiene therefore does not begin during operation, but right from the design stage of the drinking water installation. Factors relevant to this include pipe routing, sizing, insulation, circulation, the choice of fittings, and accessibility for maintenance and analysis. This then leads directly to technical responsibility within the building: high water quality must be maintained right up to the point of use.
For planning, this means that water quality must be described, documented, and ensured throughout the installation’s lifecycle. Proper drinking water hygiene therefore does not begin during operation, but right from the design stage of the drinking water installation. Factors relevant to this include pipe routing, sizing, insulation, circulation, the choice of fittings, and accessibility for maintenance and analysis. This then leads directly to technical responsibility within the building: high water quality must be maintained right up to the point of use.
Drinking water quality in Germany is of a very high standard. According to the Federal Environment Agency, over 99 per cent of samples from large, centralised supply systems meet the quality requirements.
This high quality is achieved through extraction, treatment, regular analysis and regulatory monitoring. According to the Federal Environment Ministry, there are around 5,600 water supply companies in Germany. The most important resource for public water supply is groundwater, supplemented by other water sources such as bank seepage, reservoir water and surface water.
For building projects, this starting point is an advantage. However, it does not replace on-site planning. The quality of tap water in Germany is very good at the point of supply; thereafter, domestic plumbing, temperatures, usage pattern and materials affect the medium. The legal framework is set, among other things, by the Drinking Water Ordinance. It regulates requirements for the quality of water intended for human consumption and also covers building water supply systems.
In international projects, the assessment changes. Raw water sources, disinfection methods, limit values, construction methods and operating conditions can vary significantly. A blanket assumption is therefore insufficient for tenders and system selection. Local water analyses and national requirements must also be considered early in the technical clarification phase.
Not all analysis values for drinking water quality are equally relevant for building services engineering planning. Some parameters primarily concern health assessments, whilst others influence materials, fittings, heat generators or maintenance requirements. Of particular importance are microbiological values, pH, nitrate, pesticides, lead, copper, nickel, chloride, sulphate and water hardness.
|
Parameter group |
Typical test areas |
Significance for planning and operation |
|
Microbiological parameters |
E. coli, coliform bacteria, Legionella, Pseudomonas aeruginosa |
Require appropriate temperature control, regular water replacement and the avoidance of stagnant areas |
|
Metals in pipework |
Lead, copper, nickel |
May be influenced by materials, fittings or existing installations; relevant for material selection and renovation assessment |
|
Chemical and physical parameters |
pH-Wert, Nitrat, Chlorid, Sulfat, PestizidepH value, nitrate, chloride, sulphate, pesticides |
Provide information on water quality, corrosion risks and potential material requirements |
|
Water hardness |
Calcium carbonate, magnesium |
Affects limescale formation, heat exchangers, fittings and, where applicable, the need for water softening or dosing |
In Germany, water hardness is classified into hardness ranges. The German Technical Rules for Gas and Water (DVGW) define the following values: soft below 1.5 millimoles of calcium carbonate per litre, medium from 1.5 to 2.5 millimoles per litre, and hard above 2.5 millimoles per litre.
In practice, this means that the constituents of tap water in Germany go beyond the analytical values recorded in laboratory reports. They also affect pipework systems, fittings, water heaters, maintenance intervals and operating costs. An early water analysis and consideration of these effects therefore provide greater certainty for planning, tendering and material selection.
The monitoring of drinking water quality follows a clear chain of responsibility. Water supply companies and the relevant authorities monitor water quality up to the point of delivery. Within the building, responsibility shifts to the owner or operator of the drinking water system.
This boundary is relevant for planners. Sampling points, accessibility, documentation and subsequent analysis procedures must be provided for in the building design. This applies in particular to larger buildings, public facilities, healthcare and care facilities, hotels, residential complexes, and commercially used properties.
In such cases, it is not enough simply to install pipes correctly from a technical perspective. The system must be designed so that it can be inspected, flushed and maintained. Consequently, ongoing monitoring becomes part of the technical planning.
It is therefore advisable to coordinate the following points at an early stage:
Even with very good initial quality, water can change its properties within a building. Reasons for this include stagnation, unsuitable temperatures, poor pipe sizing, dead-end pipes, inadequate insulation, a lack of hydraulic balancing, and rarely used taps.
The interaction between temperature and dwell time is particularly critical for drinking water quality. TheDVGW’s points out that drinking water should not remain in the system for extended periods, cold drinking water must remain cool, and heated drinking water must be supplied at a sufficiently high temperature. For Legionella, temperatures from around 25 °C upwards are particularly relevant, as they promote its proliferation.
Risks posed by Legionella in drinking water are prevented through a systematic approach. This includes the sizing of the pipework system, temperature control, circulation, insulation, regular use, and maintenance. Real operating conditions should be taken into account during planning: holiday periods, fluctuating occupancy, rarely used sanitary facilities, long pipe runs, or subsequent changes in use.
In addition, protection against backflow is required. Drinking water installations must be designed in such a way that no contaminated water from connected appliances, systems or non-potable water systems can flow back into the network. Safety devices in accordance with DIN EN 1717, including backflow preventers, serve precisely this purpose.
The choice of piping system determines whether drinking water quality remains stable right up to the tap. For planners, building services engineers and technical buyers, several criteria are important:
For enquiries and tenders, the framework conditions should be described as specifically as possible. These include building type, use, water analysis, operating pressures, temperature ranges, installation conditions, space constraints, national requirements, and, where applicable, special approvals.
For projects outside traditional building installations, further factors come into play. In industrial plants, on ships, in offshore areas or in specialised technical structures, vibrations, narrow shafts, salty ambient air, installation conditions, classifications and high operational safety requirements can influence the selection.
Plastic piping systems made of polypropylene (PP) are the preferred solution here. They are corrosion-free, do not release heavy metal ions into drinking water, and can be welded together with a material-to-material bond. Well-founded piping design combined with PP welding processes enables leak-tight pipe networks and reduces typical risks associated with metallic systems, such as corrosion or scaling.
aquatherm supports projects where material selection, hydraulics, system design and installation must be considered together. This applies to drinking water applications in buildings as well as industrial projects or maritime applications. If required, components and assemblies can be prepared via aquathermprefabrication to shorten installation times and make on-site installation manageable, even in confined spaces.
Drinking water quality is not a single measured value. It results from water composition, treatment, monitoring, planning, installation and operation. In Germany, the initial water quality is very high. However, maintaining this quality is determined within the building envelope.
To ensure drinking water quality in Germany in projects over the long term, water parameters, piping systems, material selection, temperature control, documentation, maintenance and usage should be considered together right from the planning stage. This results in an installation that meets hygiene requirements.
Are you planning a project with high demands on drinking water installation and pipework systems? aquatherm provides support with technical clarification, the selection of suitable systems and the implementation of appropriate solutions for buildings, industry and maritime applications.
Contact aquatherm now to arrange a project consultation.
