Drinking Water Installations:
Definition, Components, and Requirements
Drinking water installations are installed in buildings to supply cold and hot water. Flühs is a manufacturer specializing in sanitary and building services applications that produces all types of valves for drinking water installations. Drinking water installations include fittings, valves, pipes, and hot water treatment systems, which serve to provide hygienically safe drinking water.
Drinking water installations are subject to high quality requirements, as drinking water is a comestible good. There are strict limits for lead and other substances, as well as increasing regulatory restrictions on all materials that come into contact with drinking water, such as metals and plastics. This text will focus primarily on the requirements for drinking water installations in the EU.
Due to the high requirements for drinking water installations, work on pipes and other components may only be carried out by qualified personnel. Registered plumbing, heating, and air conditioning installation companies carry out work that affects the public drinking water network through permanent installations in the drinking water pipes.
This text describes what a drinking water installation is, what components it comprises, what requirements are placed on drinking water installations, and who is permitted to carry out work on drinking water installations.
What is a drinking water installation?
A drinking water installation is the entire cold and hot water system in residential, industrial, and commercial buildings.
Drinking water installations are used to supply drinking water in buildings. Drinking water is used for cooking, washing, and sanitary purposes and is a comestible good. For this reason, hygiene is a key aspect of drinking water installations. Only professional planning, installation, commissioning, and maintenance of drinking water fittings can ensure safe and hygienic operation of the system.
Various materials and installation methods are used in drinking water installations. The installation method of the drinking water pipe determines how the water is distributed in the building. A ring pipe system is a design in which the pipes run in a closed circuit. Each tapping point is supplied with water from two sides. This promotes regular water exchange and improves drinking water hygiene. Alternatively, T-piece installations are used, in which individual branches lead from a central main pipe to the tapping points. Depending on building requirements and legal regulations, materials such as brass, stainless steel, aluminum composite pipes, and plastic pipes are used in drinking water pipe systems.
Drinking water installations consist of pipes, fittings, devices for drinking water use or treatment, water meters, and a transfer point. The pipes transport the drinking water to the various tapping points in the house, for example to the sink in the kitchen or the washbasin in the bathroom, or to drinking fountains in public spaces. The fittings are used to draw drinking water and to regulate and control the flow. These fittings include, for example, taps and the mixing and shut-off valves installed in them. Instantaneous water heaters and other hot water treatment systems, as well as circulation pumps, enable the safe operation of the drinking water system. The transfer point is the point at which the drinking water installation is connected to the public drinking water supply network.
The drinking water installation consists of a large number of different components, which are described in more detail below.
What are the components of a drinking water installation?
According to DIN 1988 and DVGW regulations, the components of a drinking water installation are as follows: transfer point, water meter, water filter, shut-off devices, check valves, pressure reducers, pipes, drinking water heaters, taps, tapping points, sampling points, temperature and pressure monitoring devices, expansion tank, water softeners, and circulation pumps.
The transfer point is the point at which the public drinking water network transitions into the private domestic network. It usually consists of the main shut-off device and marks the beginning of the domestic drinking water installation.
A water meter is a device for recording water consumption that measures how much water has been withdrawn from the public network. A water meter works by means of an impeller that is set in rotation by the incoming water. In addition to the impeller water meter, there are Woltmann meters, composite meters, digital radio water meters, and ring piston meters, which use different methods to determine the flow rate.
A water filter is a device for improving water quality that filters dirt and pollutants, such as turbid materials and microorganisms, from drinking water.
A shut-off device is a component in pipelines designed to shut off or open the flow, such as shut-off valves, ball valves, or gate valves. Flühs free-flow valves ensure reliable shut-off, high flow capacity, and maximum safety in drinking water installations. Thanks to their flow-optimized design and optional integrated backflow prevention, they offer optimum functionality with minimal pressure loss – whether with a rising or non-rising spindle.
Check valves or non-return valves are components that allow drinking water to flow in only one direction and prevent it from flowing back in the opposite direction. In drinking water systems, check valves ensure that dirty water does not flow back into the public drinking water network. Flühs KFR valves (combined free-flow valves with backflow preventers) combine the functions of a free-flow valve with those of a backflow preventer in a single component. They are mainly used in the house connection area of drinking water installations.
A pressure reducer is a valve for limiting the pressure to a defined value, which is installed in pipe systems. Pressure reducers ensure that the media pressure does not exceed the preset value in order to protect the fitting from damage and keep the pressure in the pipe stable.
Pipelines are systems for conveying fluids (such as drinking water) that consist of pipes, pipe connections, pipe supports, and pipe markings. The pipes are connected to each other using detachable and non-detachable connecting elements (flanges, screws, welds).
A drinking water heater is a device for heating drinking water, which is designed as a continuous-flow heater or a hot water storage tank. It ensures the supply of hot water at the tapping points and is installed centrally or decentrally.
Taps are devices for drawing water that control or interrupt the flow of water. These include washbasin fittings with Flühs Classic, Lifetime, or Progressive cartridges, shower fittings with Flühs Thermostar thermostatic cartridges, and kitchen fittings with Flühs Promix cartridges.
A water softener is a system that filters lime from the water and ensures that hard and calcareous water becomes softer. A water softener works with the aid of a synthetic resin that filters the water flowing through it. The resin binds the lime and makes the water softer.
The circulation pump is a pump that ensures a regular hot water cycle and enables the distribution of hot water. It keeps the hot water moving in the pipes and is mainly used in buildings with a central hot water supply and several tapping points on different floors.
Sampling points are permanently installed tapping points in the drinking water system that are used for hygienic testing of the water. They enable standard-compliant water analyses in accordance with the German Drinking Water Ordinance without being influenced by fittings or tapping points.
Temperature and pressure monitoring devices continuously measure the relevant operating values in the drinking water system. They help to ensure compliance with hygienic and technical limits and are used for system control and fault prevention.
An expansion tank is a pressure-compensating container that absorbs volume fluctuations caused by temperature changes in closed hot water systems. It protects the system from overpressure and prevents unwanted dripping from safety valves.
A leakage protection system detects atypical water consumption or leaks and automatically interrupts the water supply in the event of a malfunction. It prevents water damage and provides safety in the event of pipe bursts or leaky connections.
A flushing station ensures automated water exchange in rarely used pipe sections. It protects against stagnation and bacterial contamination, especially in larger installations with many tapping points.
The components of drinking water installations and their planning, installation, and maintenance are subject to various requirements, which are described in the next section.
What are the requirements for drinking water installations?
The requirements for drinking water installations are based on high standards of hygiene, technology, and safety.
In Germany, the basic quality requirements are regulated by the Drinking Water Ordinance (TrinkwV). It sets limits for microbiological and chemical parameters and serves to protect human health. Compliance with these standards prevents the spread of Legionella and other pathogens.
The requirements for drinking water installations place a particular focus on the handling of lead. Lead can dissolve from old pipes or lead-containing connecting elements and have a harmful effect on health, especially if ingested over a long period of time. The previous limit value was 10 µg/l. From January 12, 2028, a stricter limit value of 5 µg/l (0.005 mg/l) will apply. As part of this adjustment, Section 17 (1) TrinkwV stipulates that drinking water pipes or sections made of lead must be removed or decommissioned by January 12, 2026, in accordance with generally acknowledged technical standards.
This regulation, pursuant to Section 17 (1) of the German Drinking Water Ordinance (TrinkwV), concerns the following 4 components:
- Complete lead pipes (such as in house connections or building installations)
- Pipeline sections containing lead in mixed installations
- Connections with lead-containing solder (inter alia, older copper pipes)
- Pipe sections that cause the limit value to be exceeded
It is important to distinguish between lead pipes and lead-containing alloys. Lead-containing brass alloys such as CW617N or CW614N are subject to the material requirements of the UBA positive list (in the future, the EU positive list) and may continue to be used if they were installed before January 12, 2028, and comply with the standards applicable at that time. From January 12, 2028, the use of these alloys in new drinking water installations will no longer be permitted as they do not comply with the applicable migration limits for lead.
The European requirements for drinking water are based on the EU Drinking Water Directive and the ECHA regulation. The EU Drinking Water Directive (EU) 2020/2184 has been in force since January 12, 2023, and requires all member states to implement uniform requirements for drinking water quality. Article 11 regulates, among other things, the hygienic suitability of materials that come into contact with drinking water. The European Chemicals Agency (ECHA) is working on a binding positive list of approved materials, which will come into force in 2026. Products that already have national approval (for example, in accordance with the UBA positive list) may continue to be used until December 31, 2032. From 2033 onwards, only EU-certified materials will be permitted.
All materials used are to be approved for contact with drinking water and must not release any substances that are harmful to health. The selection of suitable materials takes into account regional differences in water quality, such as pH value, water hardness, or temperature conditions.
Drinking water installations must be maintained and inspected at regular intervals. Fittings should have a certification mark, such as the DIN/DVGW mark. Maintenance and installation work may only be carried out by trained specialists.
Who carries out work on drinking water installations?
Work on drinking water installations is carried out by qualified personnel from registered specialist companies.
In order to ensure drinking water quality and compliance with legal requirements, professional planning and the use of suitable materials for drinking water installations are of utmost importance. Regular maintenance of drinking water installations in buildings ensures their functionality and safe operation.
The typical work of a specialist company for sanitary, heating, and air conditioning technology includes, for example, the installation of water pipes, the fitting of fixtures, the repair of leaks or other defects in the drinking water pipes, and the connection of household appliances such as dishwashers to the water supply.
It is not permitted for laypersons to carry out work on drinking water installations if it affects the entire network or if the installed components are a permanent part of the drinking water installation. Defective drinking water installations endanger drinking water hygiene, which is why lay work is not permitted under the German Drinking Water Ordinance.
