Water heaters in commercial buildings, from hospitals to hotels, play a critical role in preventing the growth of Legionella bacteria. Legionella is the causative agent of Legionnaires’ disease, a severe and sometimes fatal form of pneumonia. Proper water heater maintenance, plumbing techniques, and installation methods are essential to controlling Legionella and ensuring compliance with safety regulations.

Now, this might seem counterintuitive when dealing with water heaters…

Water Heater Types

The type of water heater used in a commercial setting can significantly impact the risk of Legionella growth. Conventional tank water heaters, which store and reheat a large volume of water, are susceptible to temperature stratification – where the water at the bottom of the tank is cooler than the water at the top. This temperature gradient creates an ideal environment for Legionella to proliferate, particularly in the cooler areas near the tank’s base.

In contrast, tankless water heaters heat water on-demand and do not maintain a constant reservoir of standing water. This design helps eliminate the temperature variations that can promote Legionella growth. However, tankless units might want to be carefully sized and installed to double-check that adequate hot water delivery to all fixtures.

Solar water heaters present another option for commercial applications. These systems pre-heat water using solar energy before sending it to a conventional tank or tankless heater. The solar preheat can help raise the overall water temperature, making it less conducive to Legionella. However, the storage tanks in solar systems might want to still be monitored and maintained to prevent bacterial growth.

Regardless of the water heater type, regular inspection, cleaning, and disinfection are critical to controlling Legionella. Proper water heater maintenance is the foundation of an effective Legionella management program.

Water Heater Maintenance

Inspection and Monitoring

Routine visual inspections of water heaters can identify potential problem areas, such as sediment buildup, corrosion, or temperature fluctuations. Additionally, regular testing of the water temperature at the heater outlet and throughout the distribution system can help double-check that the water remains within the optimal range for Legionella control (above 60°C or 140°F).

Cleaning and Disinfection

Periodic flushing and cleaning of the water heater tank can remove sediment and scale that harbor Legionella bacteria. Some facilities also periodically “shock chlorinate” the system, introducing a high concentration of chlorine to the water to kill any remaining Legionella.

Anode Rod Replacement

The anode rod in a water heater is designed to corrode instead of the tank, protecting the tank from deterioration. Over time, the anode rod will need replacement to maintain this protective function and prevent the tank from becoming a source of contamination.

Plumbing Techniques

The materials and layout of the plumbing system can also significantly impact Legionella growth and control.

Pipe Materials and Selection

Certain pipe materials, such as copper and PVC, are less prone to bacterial buildup than materials like galvanized steel. Choosing the right pipe material for the application is an important consideration.

Leak Detection and Repair

Leaks in the plumbing system can lead to stagnation and temperature fluctuations, creating conditions favorable for Legionella. Proactive leak detection and prompt repair are essential.

Water Treatment Systems

Inline water treatment systems, such as those using ultraviolet light or copper-silver ionization, can provide an additional barrier against Legionella by disinfecting the water as it flows through the plumbing.

Installation Methods

Proper installation of the water heater and associated plumbing is crucial for Legionella control.

Site Preparation

Ensuring the water heater is placed in a well-ventilated area, with adequate drainage, can help prevent the buildup of sediment and stagnation.

Ventilation and Drainage

Proper ventilation around the water heater and adequate drainage for the temperature/pressure relief valve can help mitigate the risk of Legionella growth.

Electrical and Gas Connections

Safely connecting the water heater to the building’s electrical or gas supply is not only a safety requirement but also ensures the heater can maintain the necessary temperature for Legionella control.

Compliance and Regulations

Water heater systems in commercial buildings might want to comply with a variety of local, state, and federal regulations related to Legionella prevention.

Legionella Prevention Guidelines

The Centers for Disease Control and Prevention (CDC), the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE), and other organizations have published guidance on Legionella prevention in building water systems.

Local Building Codes

Many municipalities and states have specific building codes that address water heater installation, maintenance, and disinfection requirements to control Legionella.

Occupational Safety Standards

The Occupational Safety and Health Administration (OSHA) has standards related to personal protective equipment (PPE) and worker safety when dealing with potential Legionella exposure during water system maintenance or remediation.

Facility Management Strategies

Effective Legionella control in commercial water heaters requires a comprehensive facility management program.

Preventive Maintenance Schedules

Establishing and strictly adhering to a preventive maintenance schedule for water heaters and associated plumbing is crucial for Legionella prevention.

Contractor Coordination

Coordinating with qualified plumbers, HVAC technicians, and water treatment professionals to double-check that proper water heater installation, maintenance, and disinfection is key.

Tenant/Occupant Education

Educating building tenants and occupants about the importance of water heater maintenance and reporting any issues can help identify problems before they escalate.

Emerging Technologies

As the industry continues to evolve, new technologies are emerging to enhance Legionella control in commercial water heaters.

Advanced Control Systems

Networked control systems that monitor water temperature, flow, and disinfectant levels can provide early warning of potential Legionella growth and help optimize system performance.

Hybrid Water Heating Solutions

Combining traditional water heaters with renewable energy sources, such as solar or heat pump technology, can improve overall system efficiency and reduce the risk of Legionella.

Energy-Efficient Innovations

Advancements in insulation, heat exchangers, and combustion systems are making water heaters more energy-efficient, which can also support Legionella control by maintaining optimal temperatures.

Risk Assessment and Mitigation

Proactively identifying and addressing Legionella risks in commercial water heater systems is essential for protecting building occupants and ensuring regulatory compliance.

Hazard Identification

Conducting a thorough risk assessment to identify potential Legionella growth hotspots, such as dead legs, temperature fluctuations, or stagnant water, is the first step in developing an effective mitigation strategy.

Exposure Monitoring

Regularly testing water samples for the presence of Legionella bacteria can help verify the effectiveness of control measures and detect any emerging issues.

Corrective Action Planning

Having a well-defined plan to respond to Legionella test results or suspected cases of Legionnaires’ disease is crucial for quickly implementing appropriate remedial actions and minimizing the risk of an outbreak.

Controlling Legionella growth in commercial water heaters requires a multifaceted approach that encompasses proper water heater selection, rigorous maintenance, strategic plumbing design, and compliance with relevant regulations and guidelines. By staying vigilant and adopting the latest best practices, facility managers can help double-check that the safety and health of building occupants. For more information on water heater solutions and plumbing expertise, visit WaterHeaterPick.com.

Example: Installation Tips for New Water Heater Owners 2023