Which factor is most likely to affect Legionella levels at an outlet?

Water stagnation is a significant factor that affects Legionella levels at an outlet because stagnant water creates ideal conditions for the bacteria to grow and proliferate. When water sits in pipes or fixtures without regular flow or usage, it can reach temperatures that favor the growth of Legionella, especially in the range of 20 to 50 degrees Celsius (68 to 122 degrees Fahrenheit). Additionally, stagnant water often has a reduced level of disinfectant, allowing bacteria to thrive.

Understanding the implications of water stagnation is essential for effective Legionella management. When water systems are not used regularly, such as in infrequent use or during periods of disrepair or inactivity, it can lead to increased bacterial populations, posing higher risks for outbreaks and infections related to Legionella.

While water temperature, water pressure, and user frequency of use play important roles in the overall management of water quality and safety, they do not impact Legionella levels at an outlet as directly as stagnation does. Proper management strategies should focus on minimizing stagnation through regular flushing of the system and ensuring a consistent flow of water to maintain safe conditions and inhibit bacterial growth.