Legionella Monitoring

What Is Legionella?

Legionella is a bacteria that can cause legionellosis (Legionnaires’ disease), a severe form of pneumonia, when inhaled or ingested. According to the Mayo Clinic, Legionnaires’ disease causes inflammation of the lungs. It can also cause infections in wounds and other parts of the body, including the heart, which may be fatal.

Why Monitoring For Legionella Is Important

Compromised Water Quality & Health Hazard: Building water systems continue to be the leading source of legionella bacteria, due to water stagnation and warm temperatures. Because legionella can grow and multiply quickly in potable water systems and survive chlorine treatment in utility water treatment plants, it’s crucial that facilities managers invest in consistent testing and treatment solutions.

Legal Responsibility: In most states, building owners and facilities managers have a legal obligation to assess and control the risk of exposure to legionella bacteria. They must ensure their water system is monitored and tested accordingly to prevent legionella outbreaks.

Creating a Water Management Program

Facilities managers are encouraged to create a water management program to monitor water flow and quality routinely. The program is designed to help minimize hazardous conditions that can lead to legionella growth, especially stagnant water. Because disinfectants can dissipate quickly from stagnant water, the opportunity for biofilm bacteria and potential pathogen growth, like legionella, increases substantially. This toolkit from the Centers for Disease Control and Prevention (CDC) provides more information on developing a water management program to reduce legionella growth and spread.

Internal Building Factors That Can Lead to Legionella Growth

• Scale and Sediment: Materials that use up disinfectant, creating ideal conditions for legionella and other bacteria growth.
• Biofilm: A biological community of bacteria that grow on moist surfaces and can protect legionella from disinfectant and heat.
• Water Temperature Fluctuation: Fluctuating water temperature can put your system at higher risk of bacteria growth.
• Insufficient or Excess Disinfectant: Too much or not enough disinfectant can compromise water quality and allow bacteria to grow out of control.
• Water Stagnation: Reduced water use and building occupancy often results in water stagnation or standing water. This lowers disinfect levels, promotes biofilm growth and reduces temperature, resulting in unsafe water quality.
• pH Level: Testing pH levels is important to understand the effectiveness of your disinfectant. Normal pH levels should measure between 6.5 and 8.5.

External Building Factors That Can Lead to Legionella Growth

• Water Quality Changes: Water quality changes can lower disinfectant levels, increase sediment and turbidity and cause unbalanced pH levels. As disinfect levels change, water management programs should be reassessed.
• Construction: Changes in water pressure or vibration from a construction site can displace biofilm, allowing legionella to permeate the water in your building.
• Water Main Breaks: If a water main breaks, biofilm can dislodge from the pressure and free legionella into the water. Additionally, sediment, dirt and other materials can enter the water and use up disinfectant more quickly.