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Stainless steel sinks increase the risk of Legionnaires’

Stainless steel sinks and kitchen taps could increase the risk of contracting deadly Legionnaires’ disease, new research reveals.

The growth of bacteria responsible for Legionnaires’, which has previously been linked to rust, is highest in stainless steel taps, a study found.  

Such taps are thought to encourage bacterial growth as their protective coating typically degrades over time, promoting rusting, according to the researchers.

The European Centre for Disease Prevention and Control (ECDC) recommends people avoid Legionnaires’ by keeping hot-water systems heated to between 50 and 60°C, as well as running taps regularly to avoid water standing for too long.

Legionnaires’ disease, which causes headaches, muscle pain, fever and confusion, affected around 7,000 people in Europe in 2015, however, the ECDC believes there may have been many more unreported incidences.

Stainless steel sinks and taps could increase the risk of contracting Legionnaires’ disease


Legionnaires’ disease is a potentially fatal form of pneumonia caused by bacteria.

The bacteria are common in natural water systems, such as lakes, as well as cooling towers. However, numbers are typically low.

If the water’s temperature allows the bacteria to flourish, people can become infected if they inhale contaminated droplets in the air.

Symptoms include fever, cough, muscle pain, headache, diarrhoea and mental confusion.

It is treated by antibiotics.

Source: Health and Safety Executive  

How the study was carried out  

Researchers from the Netherlands, including the Regional Public Health Laboratory Kennemerland, analysed four drinking water systems typically found in homes. 

All four systems, which each included stainless steel, brass ceramic and brass thermostatic mixer taps, were filled with unchlorinated drinking water.

The first system was solely filled with drinking water; the second with drinking water and cast iron rust; the third was contaminated with Legionella anisa, which is the most common strain of the bacteria in the Netherlands; and the fourth was contaminated with Legionella and cast iron rust. 

Over 34 months, 450 cold water samples were taken from the systems and tested for Legionella.

Stainless steel taps have the highest Legionella concentration

Results reveal that the stainless-steel taps containing contaminated water and added rust had the highest Legionella concentrations, with the bacteria being present in 46.4 per cent of samples.

The same tap, which was contaminated but did not contain rust in a different sample, had the bacteria present in just 14.3 per cent of cases.

The growth of Legionella species is thought to increase when the protective coating on stainless steel fixtures degrades over time. Past research has linked rust to the bacteria’s growth. 

The researchers wrote: ‘These results suggest that the type of faucet used in a drinking water system and the presence or absence of cast iron rust influences the growth of Legionella.’

They add taps should be assessed for their bacterial risk prior to sale.

Yet, Victor Yu from the University of Pittsburgh, who was not involved in the study, argued the link between such taps and Legionnaires’ is unclear without assessing the number of people who actually became ill from the disease.