Chlorine in drinking water - is there a health hazard?

Chlorine is a substance that reacts with animal and plant tissue. How dangerous chlorine is in drinking water, where and how it is used, and how chlorinated water affects the human body is therefore explained in detail here.

Chlorination for sterilization

Chlorine and chlorine dioxide are substances approved under the Drinking Water Ordinance to sterilize drinking water.

Chloride are all chlorine compounds, usually found in the water as sodium or potassium chloride. Sodium and potassium chloride are important to regulate the fluid balance of the human body. They are very important minerals for our health.

Discussion on the health hazards of chlorinated water

The chlorination of drinking water is generally harmless to health. The chlorine content of drinking water is so low that no impact on human health is feared.

More difficult to assess, however, are the degradation products and reaction products of chlorine. They are formed when chlorine meets dirt or germs. In particular, trichloromethane is considered dangerous.

Visible is polluted water mainly because it smells intensively of chlorine. This is especially known from swimming pools. The intense smell of chlorine is due to the fact that chlorine reacts with existing contaminants. When dissolved in clean water, it is odorless.

Reaction products may potentially increase the risk of individual cancers. In particular, bladder cancer is brought by science in connection with individual degradation products of chlorine. The connection has not yet been definitively proven.


After water treatment in the waterworks, the water is often easily chlorinated to prevent recontamination during transport. Chlorine or chlorine dioxide is rarely used for the actual sterilization of the water.

The ozonation of the water offers in addition to the bactericidal effect additionally has the advantage that iron and manganese are removed from the drinking water. This simplifies the preparation.

Whether transport chlorination can actually be dispensed with is questionable. On the transport routes of drinking water, it can quite come to a significant increase in germ counts.

If bacteria multiply uncontrollably during transport without being detected at the end of the transport route, there is a high risk of contamination for households.

By standing in the pipes of the house installation, it can lead to the formation of a massive biofilm and thus to further bacterial growth.

Remove chlorine from the drinking water

Activated carbon filters can remove a large part of the chlorine from the water. This also leads to a taste and smell improvement. Complete removal is only possible with the help of a reverse osmosis system.

Tips & Tricks

Reverse osmosis systems in turn bring their own disadvantages. The removal of virtually harmless chlorine alone is certainly not an argument for use.

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