Clean drinking water is a matter of course for many Germans. But it has to take a long path from water supplier to tap. Domestic installations play a particularly important role. For this is where the main risk factors for contamination of the precious resource lie. The sustainable products from the German sanitaryware industry accompany the water safely along its path, providing perfect drinking water quality.
Hygienic drinking water does not just appear from the tap: On its way to the consumer, the water first flows underground from the water supplier, via a connecting pipeline and into the building. Close to the house entry point, it passes through the water meter which marks the transition from public water supply to private drinking water plumbing. “Only few people are aware that the building owner is independently responsible for drinking water quality from this point on. It is therefore very important to provide comprehensive advice to plumbers, planners and architects,” explains Wolfgang Burchard, spokesman for Blue Responsibility.
From house connection to tap
Numerous components for drinking water protection are integrated into the plumbing system right after the water meter. This includes the legally mandatory backflow preventer, for example. It ensures that no water flows back into the public supply network which could lead to substantial hygiene problems, for example in case of a longer vacancy of a building. It is not only installed at the house connection but also in all places where contaminants could enter the drinking water system. “We offer safety valves for different liquid categories. A category 4 protection is installed between heating water and drinking water, for example. This allows even systems with antifreeze or anticorrosive agents to be connected to the drinking water system without risk,” as Marcel Wirtz from Syr explains. Filters and pressure reducers are also installed directly after the water meter. Return filters or fine filters protect the pipelines from contamination through sand or rust particles. The pressure reducer lowers the pressure in the connecting line to the maximum permitted operating pressure of 5 bar and reduces the water volume at the outlet. Pressure reducers are usually installed centrally in the cold water line after the water meter. Some manufacturers such as Honeywell offer a compact domestic water station which combines backflow preventer, backflushing filter, pressure reducer and drinking water distribution for the storage and water installation as well as storage protection groups. An outside water connection is already integrated. This is installed before the pressure reducer to ensure full pressure e.g. for a garden hose. “Rather than connecting individual components in series, the plumber can mount a time and space saving complete solution with only three screws. All individual components are perfectly coordinated,” explains Jens Bredemeier from Honeywell. Leak protection systems for installation directly after the water meter can provide additional protection against water damage. Combined solutions are available for this as well, e.g. from Syr. “Individual valves from water treatment, hygiene monitoring, heating water treatment and leak protection are connected via the internet so they can exchange information. The devices are controlled through an app, for example,” explains Marcel Wirtz from Syr. A hygiene rinsing system which monitors the entire water circuit can be integrated at the start of the drinking water plumbing system or alternatively after the last outlet.
After the water has flown through the first components, it usually goes different ways. Some flows into the sanitary items as cold drinking water, e.g. into the toilet, while another part flows into the central drinking water heating system. For hygiene reasons, the storage temperature for heated drinking water has to be 60 °C. From the hot water storage tank, the water flows through the distribution pipes in the cellar and risers into the stories of the building and to the desired outlet. With over 400 litres of storage and/or a pipe capacity of more than three litres between the outlet of the hot water storage tank and the most remote outlet, parallel or internal circulation systems have to be installed for reasons of comfort and hygiene,” explains Dirk Thielker from Viega. It has to be ensured that the temperature of the circulating hot water does not fall below 55 °C. “Proper insulation of cold and hot water pipes also has to be ensured at all times as perfect quality of the drinking water can only be provided if the stipulated temperatures are maintained,” says Joachim Hildebrand from Mepa. Cold water is also distributed to the individual stories. “How the pipes are routed within the stories is of particular importance here,” explains Volker Röttger from Geberit. “There is a high risk of germ growth when the pipes are not in use. Serial pipelines with placement of the most frequently used consuming unit – usually the toilet – or closed circuits are the best solutions.” Within the stories, water flows to the consuming points such as toilets, sinks, kitchen taps, showers as well as washing machines or garden taps. Individual hygiene rinsing systems can also be installed directly after the outlets. “This provides reliable protection for e.g. the infrequently used sink in a utility room, for example,” explains Joachim Hildebrand from Mepa. They system avoids stagnation as well as critical temperatures by means of forced rinsing. After use of the individual outlets, the water is routed to the wastewater lines and fed into the public wastewater system.
Proper operation and planning to demand
In addition to the individual components, expert planning and proper operation are crucial factors for drinking water quality. “Drinking water plumbing should use the smallest pipe diameters possible and only few surfaces in contact with water. A high flow rate is an additional advantage,” explains Reinhard Bartz from Franke Aquarotter. Correct dimensioning is also crucial for proper operation. “In reality, planning is often not targeted to actual demand and drinking water plumbing systems are overdimensioned. The building owners should therefore be involved more in planning to demand as they will later have the responsibility for the operation of the system conforming to hygiene and other regulations,” Bartz summarises.