For potable water systems, could opportunities to prevent Legionnaires' disease be missed if test results are interpreted by concentration alone?

The assertion that opportunities to prevent Legionnaires' disease could be missed if test results are interpreted solely by concentration is correct. Focusing only on the concentration of Legionella in water samples does not provide a complete picture of the potential risk factors associated with Legionella growth and transmission.

Legionella bacteria thrive in certain environmental conditions, particularly within specific temperature ranges and stagnant water environments. For example, water temperatures between 77°F and 113°F (approximately 25°C to 45°C) favor the growth of Legionella. If monitoring focuses only on bacterial concentration without considering these other critical factors—such as temperature, water age, system design, and the presence of biofilm or sediment—potable water systems may remain a risk for Legionnaires' disease, even if Legionella concentrations appear low.

Comprehensive management of Legionella risks involves looking at various parameters that contribute to the bacteria’s survival and proliferation, not simply measuring its concentration. Therefore, incorporating a more holistic approach that considers environmental conditions alongside concentration levels is essential for effectively managing the risks of Legionella in potable water systems.