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🇫🇷 France /Disasters & Emergencies

France Heatwaves: Is Lukewarm Tap Water Safe to Drink?

From Le Figaro · () French

Translated from French, summarized and contextualized by DistantNews.

At a glance

News Named sources Context piece
  • French tap water temperatures are regularly exceeding 25°C during heatwaves, raising health concerns.
  • Higher temperatures can promote the growth of bacteria like Legionella, which can cause respiratory illnesses.
  • Experts advise running taps for a few minutes to ensure water is cool, though tap water remains highly controlled.

As France endures intense summer heatwaves, many are finding their "cold" tap water has become uncomfortably warm, often exceeding 25°C. This temperature, a reference point for potable water, has sparked questions about potential health risks. The warming affects water at multiple stages: rivers and rivers, which supply a third of France's drinking water, are heating up, with the Garonne River reaching 28°C in the southwest. Distribution networks also see temperature increases, particularly within buildings where indoor pipes are directly exposed to the heat.

Beyond 24 hours without opening the tap, it is advisable to let the water run for a few minutes until it feels cool or at least lukewarm.

— Nathalie DavoisneDirector of the Center for Water Information (Cieau), explaining how to manage warm tap water during heatwaves.

The elevated temperatures create a favorable environment for bacterial growth, notably Legionella. These bacteria thrive in stagnant water between 25°C and 45°C and can lead to flu-like symptoms or severe pneumonia. "Beyond 24 hours without opening the tap, it is advisable to let the water run for a few minutes until it feels cool or at least lukewarm," advises Nathalie Davoisne, director of the Center for Water Information (Cieau). This recommendation, however, applies even outside of heatwave periods.

The 25°C limit is a reference for comfort, but not a health limit.

— Nathalie DavoisneDirector of the Center for Water Information (Cieau), clarifying the significance of tap water temperature.

Davoisne emphasizes that the 25°C threshold is more about comfort than a strict health limit. She points out that tap water in France is among the most rigorously controlled consumer products, undergoing nearly 18 million checks annually. Water treatment processes are adapted to source quality, though treating warmer water requires more resources. "It is more difficult to treat water at 25 degrees because micro-organisms develop," noted Yann Ouda in July, highlighting increased costs due to higher chemical and energy usage.

It is more difficult to treat water at 25 degrees, because micro-organisms develop. This affects the cost, as we use more products and more electricity to treat the same water as in normal periods.

— Yann OudaAn expert commenting on the challenges and costs associated with treating warmer water.
DistantNews Editorial

Originally published by Le Figaro in French. Translated, summarized, and contextualized by our editorial team with added local perspective. Read our editorial standards.

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