Legionella

Legionella bacteria can grow in your home’s water system when not in use. Here's some advice on how you can prevent it in your home.

What is Legionella?

Legionella is a form of bacteria that can be found in various bodies of water, from streams to lakes. However, it can also be found in mains water and can enter a home’s water system.

Legionella growth in a home water system is rare, but the chances are increased during periods where the water system isn’t being used, such as when you’re away on holiday. This is because the lack of water turnover in your home (e.g. not running a tap or flushing the toilet) leads to the water stagnating, which provides good conditions for Legionella bacteria to grow. 

What can you do?

To minimise the risk of exposure to Legionella bacteria, we recommend that you do the following:
 

  • When returning to your home after being away for some time (over seven days), flush all outlets for at least 2 minutes. Make sure that you don’t create a spray when you do this (for example, by not having the tap running too fast) that could expose you to the bacteria. This flushing should reintroduce fresh water to your system and remove any bacteria.
  • De-scale taps and showers where there is a noticeable build-up, as legionella can grow on scale and rust.
  • Legionella grows best between 20C and 50C, so make sure your water temperatures are correct. Keep hot water cylinders at 60C, and cold water usage at 20C or below.