Legionella under the microscope

2 Oct 2013

Top 3 tips on how to prevent Legionella


Legionnaires’ disease is a real concern for many, particularly with the recent outbreaks which could have been prevented. There are many ways to reduce the risks associated with Legionella and as experts in the control, management and prevention of Legionella, the team at W.E.T are here to help you achieve compliance. There are three quick tips you can use to prevent the growth of Legionella in your water system.

Tip 1 - Temperature control

This is one of the most effective ways to control Legionella growth as well as meeting your legal duty under the Health & Safety at Work Act 1974.

Below is a quick overview of the temperatures water should be stored and distributed at;

  • Water which is stored in a hot water storage cylinder should be 60⁰C or higher*
  • Hot water which is distributed should be at 50⁰C or higher
  • Water which is cold should be stored AND distributed below 20⁰C

*but be careful not to take the temperature too high as this could result in scalding and high energy bills!

Tip 2 - Be aware of stagnant water

Stagnant water presents the perfect breeding ground for Legionella growth. With this in mind it’s important to remove dead ends in pipe-work (i.e. lengths of pipework which previously fed an outlet but are now redundant) and flush outlets which are not being used on a regular basis. This includes taps and showerheads.

Tip 3 - Clean and maintain

It’s important to develop a clear plan of action to ensure that you are doing everything possible to actively prevent Legionella growth. Cleaning and ongoing maintenance is an essential part of this, and as such it’s important that infrequently used outlets are flushed weekly (minimum), cold water tanks are cleaned periodically and hot water cylinders should be drained and checked for signs of corrosion and debris.


These are just a few suggestions from W.E.T which form part of a control scheme, which is required by law. If you want more information on Legionella control or are concerned that your water system isn’t compliant, then contact us here at W.E.T, we will be happy to help and advise.

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