Can legionella resist high water temperatures?
Once legionella is in contact with water at temperatures greater than 60C it is normally killed within five minutes. However, it can be very difficult to maintain high water temperatures in large systems, legionella can hide in cooler areas where there is sludge, deadlegs etc and within thermo-tolerant hosts such as amoeba. It would be prudent to expect legionella to survive in all central water systems in low numbers (Re: PHLS National Survey). It is normally when legionella reach deadlegs that the real hazard starts to develop.
