I have two questions:
1) I am about to clean up a bathroom that has not been in use for four months. Would flushing the taps for ten minutes get rid of any Legionella? It is on the second floor of a two story detached house. Should I take any other precautions?
2) Can the air conditioning system in cars ever contain Legionella?
Flushing out the stagnant water is not a bad idea, but not particularly effective against Legionella, since Legionella is in the biofilm encircling all the pipes and fixtures. A brief flushing for several minutes is ok if the water is to be used for drinking.
The risk to individuals living in a home with Legionella in the water system is almost nil if you are in reasonably good health. If any of the residents of the home have a chronic disease, we recommend that tap water not be drunk – either in the home or elsewhere. Recommendations are to boil tap water, cool it, and store it in a pitcher for later drinking.
There are two reports in scientific literature suggesting that air conditioners in cars might cause Legionnaires’ disease. We are highly skeptical of the validity of either report.