Drinking water hygiene – clean water is the basis for life

Drinking water quality in Germany is among the highest anywhere in the world. This quality is guaranteed by the local water utility. To ensure that every user also enjoys this high quality, the drinking water installation in the building must be working properly and water must be regularly used – and thus ‘restocked’ – at the tapping points. Building owners and managers must keep the drinking water in a sound technical condition while also making sure that the building users are aware of the importance of regular water exchanges. After all: pipes and fittings are the ‘packaging’ for this most important ‘foodstuff’ – our drinking water. And, like any other foodstuff, drinking water has a ‘shelf life’: it needs to be used regularly and therefore continuously ‘restocked’ in the installation. In much the same way as we buy new items of food to restock our fridges, for example.

First-class drinking water
What’s the shelf life for drinking water?
Who makes sure drinking water is safe to drink?
Electronic taps safeguard drinking water hygiene
Summary: Drinking water hygiene is essential

Drinking water in Germany – first-class quality

Drinking water in Germany is our most tightly regulated foodstuff. Drinking water undergoes a wide range of microbiological and chemical testing to confirm compliance with the German Drinking Water Regulation (TrinkwV). Local water utilities must also ensure security of supply – even when faced with changing environmental conditions like rising temperatures or the impacts of climate change. And we should be very proud of their achievements. Yet from the service connectiononwards, every owner and user is themselves responsible for maintaining water quality. A few key rules need to be followed here.

Tap water versus bottled water

A direct comparison shows that tap water in Germany is subject to an extremely tough testing regimen and is in fact more tightly regulated than bottled mineral water. At the same time, tap water has a much smaller ecological footprint, as it is supplied to every household as a matter of course. This makes tap water not only safer in hygienic terms but also a more sustainable alternative to bottled water. Drinking tap water not only avoids supply chain emissions but also microplastics, as most water is sold in PET bottles.

Water out of the tap also costs next to nothing: anyone drinking around a litre a day (including tea, coffee, etc.) pays 0.4 cents a litre for 365 litres – just EUR 1.46 a year.

Drinking Water Hygiene Day: raising awareness and keeping water safe

Drinking Water Hygiene Day on 1 December aims to make us aware of how precious our clean drinking water is – and how important it is that we handle this resource responsibly. The annual event reminds us that utilities, building operators and users share responsibility for protecting the quality of our most important foodstuff, so as to ensure health, quality of life and the sustainable use of water as a resource.

Fresh drinking water: safe to drink, but for how long?

Water is a natural product and therefore has a natural shelf life. When it stops flowing and just ‘sits’ in the piping, a process of change begins. This stagnation, as it is called, affects freshness even after only a few hours, as materials can then start to leach into the water. Stagnation times of more than four hours are therefore already considered too long for drinking water that will be used to prepare food – especially for infants and pregnant women. This water can be used for washing up, watering plants or similar activities, however. If the drinking water stays unused for even longer, microorganisms can rise to unsafe levels after around 72 hours. This includes pathogens like Legionella, which is naturally found at low concentrations in water but can present a health risk if allowed to proliferate to excessive levels. Wherever air-water mixtures can form – not only the obvious example of showering but also during hand-washing – there is a significant risk of infection: Legionella preferentially propagates at temperatures between 30 °C and 45 °C, and can enter the lungs if present in water mist that is breathed in. This water is nonetheless still safe to drink.

How to keep drinking water fresh

Drinking water stays hygienic when it is regularly used, i.e. exchanged in the piping, and especially after longer interruptions to use like weekends or holidays. On your return, leave the cold water tap to run until the water is cool and fresh again. A simple and effective test is to run the water across the back of a hand. In older buildings, having the installation materials checked is recommended, to avoid health risks like lead piping. Regular maintenance of fittings and other parts in the drinking water installation also provides additional support for ensuring long-term water quality and security of supply.

Reference values for fresh water

Stagnation of less than 4 hours: water is safe to use
Stagnation of up to 72 hours: let tap run briefly before drinking, otherwise safe
Stagnation of over 72 hours: prolonged use or stagnation flush urgently recommended

Sharing responsibility – who ensures drinking water is safe?

Responsibility for drinking water hygiene is an endeavour shared among multiple stakeholders:

Water utilities: guarantee quality up to the service connection
Owners/landlords and building operators: bear responsibility from the water meter onwards for the drinking water installation and perform legal duties like Legionella testing
Users and residents: support overall hygiene with regular usage and stagnation flushes

Recommendations for action for tenants and users

For drinking water to stay fresh and hygienic, users should let the cold and hot taps run briefly until the water reaches the right temperature. Fittings should be kept clean and flow regulators should be descaled or replaced as necessary. If properties are vacant for longer periods, owners or facility management must take appropriate action to maintain the water quality.

Electronic fittings offer automated hygiene flushes

During interruptions in use, electronic fittings from SCHELL perform automated stagnation flushes and so ensure the regular exchange of water – without manual intervention being necessary. This is established practice in buildings for public use, but is also gaining ground in the private setting – as in kitchens or guest WCs. These fittings not only significantly enhance user comfort, but also reduce the hygienic risks that result from stagnating water. This technology is especially useful in rooms that see only occasional use, in important areas like kitchens or in the event of a prolonged absence.

Targeted installation of electronic fittings

Electronic fittings should be used in key locations like kitchens or guest WCs.
Tapping points located at the end of the installation ensure throughflow in the entire supply system.
Individual fittings should be flushed through after longer periods of absence.
Stagnation flushes protect health and should not be seen as ‘wasting water’.
An automated exchange of water every three days adds up to only a few litres of water.
In comparison, daily water consumption is significantly higher.

Summary – drinking water hygiene protects our most valuable foodstuff

Clean drinking water should not be taken for granted. While the high quality achieved in Germany is the result of long-standing safeguards and tight regulation, drinking water hygiene in buildings depends on responsible handling, regular use and maintenance to professional standards. Electronic fittings can make an important contribution here by enabling automated flushes and so avoiding excessively long periods of stagnation. In this way, operators and users act together to safeguard water quality in buildings.Properly implemented, drinking water hygiene protects health, ensures quality of life and secures the sustainable use of water as a resource.