Resistance of Legionella to chlorine?

There are claims that Legionella can survive at a chlorine level of 5 ppm at pH 7.0-7.5 in tap water. What is your opinion of this?

There are multiple reasons for the relative resistance of Legionella to chlorine. These include an outer membrane with ubiquinones and other fatty acids, intracellular location within cysts of amoebae, and genetic responses to oxidative stress from exposure to chlorine.