Legionella bacteria can be amplified or incubated to the point where the bacteria multiplies when the right conditions are present.
The legionella growth range has been identified in laboratory testing to show that Legionella bacteria will grow at temperatures between
68 and 122 degrees Fahrenheit. Legionella bacteria has an ideal growth range where it reproduces at an accelerated rate between 95 and 115
degrees Fahrenheit (Diagram 1 – How Legionella Bacteria Responds to Water Temperatures ).
There are many sources in a building water system that can contribute to amplification of Legionella bactera that is commonly present,
in small amounts, in a building water distribution system. Municipal water systems typical introduce chlorine or mono-chlorines to minimize
bacteria in the public water supply. Small amounts of organic pathogens, including Legionella, can be introduced into a building water distribution
system and the amounts of bacteria can vary from one time of the year to another. There are three common factors that can contribute to increases
of Legionella in the water supply. The three factors are water temperatures in the ideal growth range, stagnation and mineral build-up or biofilm in the piping.
Stagnation allows the chlorine to dissipate and the warm temperatures create an environment for Legionalla growth on the biofilm on the walls of the pipes or equipment.
Contributing Sources of increased bacteria counts
1) Water Main Construction – Water main construction can dislodge bacteria in the biofilm and mineral build-up on the walls of the water mains.
One way to minimize large doses of Legionellae from being introduced a duplex catridge type filter into the piping system, at the meter.
The filter can then catch the debris and organisms that Legionellae can feed off of.
2) Warm environment -A warm environment can leave the piping systemslide2-2 valves, tanks, etc in the ideal growth range for Legionellae.
Many pipes and equipment are located in spaces or environments that are in the idea growth range for Legionellae. When these piping systems
are in the ideal growth range, they should be circulated or treated to minimize the bacteria growth.