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Drinking water: Bonn residents wonder about chlorine smell

Drinking water : Bonn residents wonder about chlorine smell

Some Bonn residents may notice their water smelling a little more like chlorine than usual from time to time. The WTV is the company that provides water for Bonn residents and they explain why this may occur.

"Why is there such a strong smell of chlorine here?", numerous tenants and homeowners in Bonn are currently asking themselves when they enter their bathrooms. Some have been noticing this smell for several weeks, maybe even months. Where does this chlorine smell come from if you haven't just been to the swimming pool or used chlorine-containing agents to clean the bathroom?

If you ask the Bonn Stadtwerke municipal utility directly, the company refers you to the Wahnbachtalsperren-Verband (WTV). The WTV ensures that around 800,000 inhabitants in Bonn and the Rhein-Sieg district are supplied with clean drinking water. The drinking water produced by the WTV is obtained from two different sources: One part comes from the Wahnbachtalsperre water reservoir, the other from groundwater wells in the Hennef Siegbogen and in Sankt Augustin-Meindorf. The water from both sources is treated with chlorine dioxide to kill bacteria. This process is not harmful, and is carried out in accordance with the Drinking Water Ordinance in accordance with the health authorities.

The causes of the strong chlorine odor are not maintenance work on the WTV supply network or necessary purification of the water, as one might assume. If it occasionally happens that you notice a stronger chlorine smell in your own home, it may be because the water composition has been changed, which is not at all unusual. "Normally, drinking water consists of about 80 percent dam water and about 20 percent groundwater. But the ratio can sometimes change to 70 to 30 or 60 to 40," says Dirk Radermacher, head of construction and operations management at WTV.

When the dam is not so well filled, the water comes more from the groundwater wells. "A major construction site in the area can also lead to higher groundwater levels," explains Sabine Engels-Schwarzlohe, head of the Laboratories Department at WTV. Water quality is permanently monitored in the WTV laboratory. WTV has developed a variety of processes for this purpose. From dam monitoring to regular sampling and continuous monitoring with online measuring devices to filtration of the water with UV disinfection, water control consists of various stages. According to the WTV, the increased chlorine odor in the bathroom may persist for several weeks. Some residents of Bonn had already noticed this smell at the end of 2020, but most seem to have remained relaxed about it: "We have had no significant inquiries about this. Only a few via social media, which we answered directly. However, that was last December, and we haven't had any since," says Lea Hoffmann from the Stadtwerke press office.

(Orig. text: Sebastian Flick; Translation: ck)