Chlorine, or its derivatives can, because of their oxydizing action, control the proliferation of the Legionella.The chlorine-based products are pumped continuously into the water with an amount of product of 0,5 to 2ppm , or as a series of shocks measuring 20-50 ppm.

ADVANTAGES :

The chlorine-based products being injected directly into the water, they can reach the whole of the network;

DISADVANTAGES:

• The chlorinated water becomes corrosive and necessitates a complementary treatment with additional chemical products. Moreover, the corrosive quality of the water increases along with the temperature.
• Chlorine stops the proliferation of the Legionella, but doesn’t eradicate the colonies. If the injection of chlorine stops, the infection of the network by the bacteria can happen very fast.
• Recent epidemiologic studies show that the risk of having a cancer is to be linked proportionally with the concentration of chlorine that can be found in the water.
• The cost of the injection equipment is sizeable. The maintenance and the regular testing of the water are quite tedious.