💧 House Installations and the Hidden Dangers: Why Drinking Water Testing is useful in Swiss Households

Switzerland is rightly known as the "Water Tower of Europe." Our public drinking water mostly comes from protected groundwater and spring sources and is monitored at the highest level by water suppliers. However, this guarantee does not extend to your tap, but stops at the house connection.

From the point of transfer, the responsibility for water quality lies with the property owner or operator of the building. This is legally defined in the Ordinance on Drinking Water. The final meters to your glass often harbour the greatest risks.

The Greatest Underestimated Dangers in Your Pipes

Even if the water flowing into your house is of the best quality, it can come into contact with unwanted substances on its way through the house installation. Two sources of danger are particularly relevant:

1. The Risk of Heavy Metals (Lead, Nickel, Copper)

Especially in older buildings constructed before 1970, **lead pipes** may still be installed, which release the heavy metal into the drinking water. Although lead pipes have been banned in Switzerland since 1904, the risk remains in old buildings.

Even if your house is newer, **fittings** (taps) and certain alloys (e.g., brass or red brass) can release **lead or nickel** if the water stands in the pipes for a long time (stagnation). This can be particularly harmful to pregnant women, infants, and young children. The maximum value for lead in drinking water is **10 µg/l**, according to the EDI Ordinance.

2. The Germ Trap Legionella

Legionella are bacteria that occur in natural waters but multiply particularly well in **lukewarm, stagnant water**. The risk is almost exclusively in hot water systems (boilers, tanks).

[Illustration of Legionella bacteria growth cycle in water systems]

• Ideal Temperature: Between 25°C and 45°C (the ideal breeding ground).
• Stagnation: Rarely used hot water pipes, dead ends, or poorly circulated boilers.
• Transmission: Legionella is harmless if consumed. It becomes dangerous when inhaled via **aerosols** (fine water droplets) – typically during showering.

When is Professional Water Testing Necessary?

Self-monitoring by the property owner is crucial in Switzerland, as emphasized by the Swiss Gas and Water Industry Association (SVGW) in its guidelines (W3/E4).

A water test is strongly recommended if any of the following apply:

• Your building was constructed before 1970.
• You have long cold water run times, or cold water pipes run near the hot water system (risk of Legionella growth in cold water).
• After major renovations or replacement of fittings.
• After long absences (holidays/operational interruptions).
• Infants, young children, or immunocompromised individuals live in the household.

➡️ Know What You Drink – With a Water Analysis

Don't wait until the problem becomes obvious. You only get certainty about the actual quality of the water flowing from your taps through an independent laboratory analysis.

If you want to check the contaminants in your house installations **quickly and easily** in Switzerland, umweltcheck.ch offers a range of accredited water tests.

On umweltcheck.ch/Wassertests/ you can:

• Select the appropriate test (e.g., for Legionella, heavy metals, or general microbiology).
• Order your test kit comfortably to your home and take the sample yourself.
• Receive a thorough analysis from a certified laboratory, showing whether legal limits are exceeded.

Act proactively for your health!

Further Information and Sources:

• Federal Food Safety and Veterinary Office (FSVO): Monitoring of Drinking Water Quality
• Legionella Prevention: Recommendations of the FOPH/FSVO (PDF)