Folks, just to set the record straight, swallowing legionella will NOT lead to Legionaire's Disease (Legionella pneumophila). The only way you can contract this is through breathing in a very fine mist containing the bacteria. The mist droplets then need to be tiny enough to be able to reach deep into the lung before they will multiply to create a problem. In fact, the bacteria is generally only harmful to those with a compromised immune system and the elderly.

Just clarifying that you won't catch Legionaire's by drinking contaminated water, but I do agree that you can certainly catch it by breathing in the vapours.

Gerry

The problem was not any tempering valves. The problem was caused by lowering the boiler temperature so it was around the tempered temperature in the delivery pipes. It was in the large volume of the boilers where the Legionnaire bugs were bread. There were several hospitals concerned, they were all instructed to raise the temperature of their HWS to conform with legislation.

For the same reason, when you start up your HWS you should let it come up to temperature and leave it running for 40 minutes or more at high temperature before switching it off.

Hi Gerry,
You forgot to add that it could also be filtered out by a beard.......but don't lick your lips.
What gets me with this stuff is that folks walking 50 metres away have caught the virus from some tower or other and then you have to track down the culprit.And often the bug is in well maintained cooling towers.
I installed a fairly big cooling tower for my son in law and it is very efficient. We get it maintained by a contractor monthly and the health board have very stringent testing on these things.
And yes the ill or elderly are suseptable , that's why I recommend no taking of chances with hot water units.
A Hot water System is one thing. A tepid Water system is another.