If faucets are not used for a long period, germs and contaminants can form in the water during absence.

For example, if you and your family just returned from a long vacation or for any other reason have not been home for an extended period, you should refrain from using the water from the faucet immediately. Even less should you use it immediately as drinking water. When you return from your extended absence, it is recommended to let the stagnant water run first. It is recommended to flush the water line with at least 10 liters of water. But does this make the water clean?

Danger from Legionella

Our Swiss tap water is very clean, but not sterile. For this reason, stagnant water in the pipes is particularly susceptible to the formation of germs. If the faucet is not used for a long period, stagnant water provides optimal conditions for the formation of Legionella.

Legionella are harmful bacteria that can be dangerous for us, especially at high concentrations in water. If tap water is contaminated with these germs, they can quickly spread throughout the bathroom or anywhere tap water is frequently used. 

Legionella do not enter our bodies through drinking water, but are mainly inhaled. Through small water droplets, also called aerosols, the germs enter our airways and can make us sick. To prevent this from happening, it is best to take appropriate measures before a long absence.

Home and vacation preparation - what you can do 

One of the most sensible measures you can take when preparing your home for vacation is to turn off the water completely before you leave. However, to completely shut off the water, it is not enough to simply close the valve at the faucet. Since all the water pipes are connected, once germs have formed in one part of the building, they will spread throughout the entire water system. Instead, you need to close the main water valve or the main shut-off valve.

What is the main water valve and how do you turn off the water there? 

The main water valve is responsible for the entire water supply in the house or apartment. When it is turned off or on, no more water will enter the pipe system until it is turned on again. In most houses, the main shut-off valve is located in the basement. However, if you are renting, for example in an apartment, the main shut-off valve is often located in the kitchen or bathroom, usually somewhat hidden. If in doubt, you should contact your landlord and inquire. 

Turning off the main water valve before a long absence is one of the most important preventive measures you can take. As soon as you return from your long absence, the main shut-off valve must be opened again. However, you should always follow the first tip and let the water run for a while before using it. Neither turning off the main shut-off valve nor letting the water run longer will provide 100% safety. For ultimate safety, a water analysis is recommended.

Only a water analysis provides ultimate safety 

With a water analysis, you can have your tap water examined by a professional laboratory and get a solid statement on how pure and clean the tap water actually is. You can initiate a water analysis yourself without prior knowledge by ordering a water test, taking a sample with it, and then sending it back to the laboratory. The sample is then analyzed, and the result evaluated. A water analysis not only provides a binding statement regarding water purity, but it also gives you additional metrics that provide a detailed insight into the quality of the tap water. The water is tested for various pollutants, germs, and bacteria. In fact, a water analysis is not only useful if the water has potential germs and bacteria during absence but also beyond that. 

You do not need to conduct a water analysis every month, but an annual analysis of your tap water is highly recommended. Especially if you frequently use tap water for food preparation or have children and infants in the house, you should be sure that the tap water meets the necessary quality standards. If a water analysis reveals that the water is contaminated, you can then get to the root of the problem. In addition to stagnant water, broken or old pipes are often responsible for various contaminants in your water.