There have been several high-profile cases of Legionella outbreaks in 2026, highlighting the importance of detection and prevention.
Unfortunately, Basel experienced one linked to cooling towers, with 26 people falling ill and one person dying. This followed the outbreak follows a recent Legionnaires’ disease cluster in New York’s Upper East Side, where seven people died and more than 90 fell ill. Live Legionella bacteria were found in samples from 59 cooling towers across 58 buildings there.
Installer spoke to Hayley Holland – Head of Marketing at Hydrosense – to find out how plumbers and heating engineers can ensure they’re protecting the public health:
The hidden risk of Legionella
Legionella is bacteria that can develop and multiply in water sources like heating systems and where there’s stored water. The bacteria can cause Legionnaires’ disease, which is a serious condition caused by breathing in the legionella and can lead to illness and even death.
“Wherever there’s water, and wherever there’s humans, there’s risk,” Hayley explained.
“There are about 60 species of Legionella worldwide, and about 28 of them can affect human health. Legionella pneumophila is the one that causes about 90% of cases, so that’s the one you need to find.
“You can’t control bacteria, it’s stubborn and determined. When you’re responsible for water, you need to look after the system and ensure that it’s safe.
“Sometimes people don’t want to know legionella is in the system because if you find it, you have to act,” Hayley explained. “Ignorance can feel like bliss, but finding it is the best thing. If you detect it, you can act quickly and sort it out.
“It’s a message that we want to get across to installers and building managers. Accept that legionella can exist in any system if it’s not maintained and managed, so test to ensure that it’s not in there.”
How to test for Legionella
In the past, testing water systems meant installers had to take samples and send to a lab for the results, which could take days or weeks.
Hydrosense has developed an on-site rapid testing solution which detects Legionella pneumophila serogroups 1-15 in just 25 minutes.
“The test kits take five minutes to set up, and you can have an accurate result in just 25 minutes,” Hayley explained.
“The kits also detect VBNC (Viable But Non-Culturable state) bacteria, which not a lot of installers know about. VBNC is when the bacteria essentially goes into survival mode when a water system is shocked with high heat or biocides are used to try to get rid of it. It’s still alive and still infectious but goes dormant, essentially sleeping in the system.
“So you may have found the problem and thought you’ve solved it, but the bacteria is still in there. Traditional labs can’t detect Legionella when it’s in the VBNC state, but our testing kits can.
“We do believe that every plumber and heating engineer should have a Legionella test kit in their van. It’s safety first, but it’s also a value-added service. If you go into the system and find a potential problem, you can test there and then. If there’s a problem, you can remediate it there and then, and you will have acted as quickly as you possible could. Then you can test again, ensure the system is safe, and you’ll have a very happy, and safe, customer.”
Find out more at: Hydrosense – The worlds’ fastest Legionella tests
