Water heaters play a critical role in providing hot water for businesses, hospitals, hotels, and other commercial facilities. In our 10 years of water heater experience… However, these systems can also pose a serious health risk if not properly maintained – namely, the potential growth and spread of the Legionella bacteria. As an experienced water heater specialist, it’s essential to understand the complexities of Legionella control in commercial water heater systems and employ best practices to safeguard public health.

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

Understanding Legionella Risks

Legionella is a naturally occurring bacterium commonly found in freshwater environments, such as lakes, rivers, and groundwater. While typically harmless when ingested, Legionella poses a significant threat when aerosolized and inhaled, as it can cause a severe form of pneumonia known as Legionnaires’ disease. ​ Commercial water heater systems, with their warm, stagnant water and ample biofilm growth, provide an ideal breeding ground for Legionella.

The risk of Legionella contamination is especially high in facilities with large, complex plumbing systems, such as hospitals, hotels, and high-rise office buildings. When Legionella-laden water is aerosolized through showers, faucets, cooling towers, or other water fixtures, it can be easily inhaled by building occupants, putting them at risk of infection.

Preventive Measures

Effectively controlling Legionella in commercial water heater systems requires a comprehensive, multi-faceted approach. Here are some key preventive measures:

Temperature Management: Maintaining the water heater temperature between 140°F (60°C) and 160°F (71°C) is critical. This high temperature range helps to kill off Legionella bacteria and prevent their proliferation.

Disinfection and Flushing: Regular shock chlorination or other disinfection methods, combined with thorough flushing of the entire plumbing system, can help eliminate Legionella and prevent biofilm buildup that serves as a breeding ground for the bacteria.

Plumbing Design and Materials: Utilizing proper plumbing design and materials, such as copper or PEX piping, can minimize the risk of Legionella growth. Avoiding dead-legs, stagnant water, and other plumbing configurations that allow water to sit for extended periods is also essential.

Monitoring and Testing: Implementing a comprehensive Legionella monitoring and testing program is crucial for early detection and prompt remediation. This may include regular water sampling, analysis, and documentation of results.

Cooling Tower Maintenance: For facilities with cooling towers, proper cleaning, disinfection, and maintenance of these systems is vital, as they can harbor and spread Legionella if not properly managed.

Employee Training and Education: Educating facility managers, maintenance staff, and occupants on the risks of Legionella and the importance of proper water heater and plumbing system maintenance can help promote a culture of vigilance and proactive prevention.

Monitoring and Maintenance

Effective Legionella control in commercial water heater systems requires ongoing monitoring and maintenance. This includes:

Routine Inspections: Regularly inspecting water heaters, plumbing systems, and associated components for signs of scale buildup, corrosion, or other issues that could compromise water quality and promote Legionella growth.

Water Quality Testing: Implementing a comprehensive water quality testing program to monitor for Legionella and other contaminants, both at the water heater and throughout the plumbing system.

Preventive Maintenance: Performing regular maintenance tasks, such as flushing the water heater, cleaning aerators, and replacing components like temperature and pressure relief valves, to double-check that the system is operating efficiently and safely.

Recordkeeping and Documentation: Maintaining detailed records of all maintenance activities, water quality test results, and any Legionella-related incidents or remediation efforts. This documentation can be crucial for demonstrating compliance with applicable regulations and guidelines.

Regulatory Compliance and Guidance

Navigating the regulatory landscape surrounding Legionella control in commercial water heater systems is crucial. While there are currently no federal regulations specifically addressing Legionella in drinking water, several industry guidelines and standards provide valuable guidance, including:

• CDC Legionella Guidance: The Centers for Disease Control and Prevention (CDC) have developed comprehensive guidelines for the prevention and control of Legionella in building water systems, which serve as a widely recognized industry standard.
• ASHRAE Standard 188: The American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) has published Standard 188, which establishes minimum Legionella risk management requirements for building water systems.
• OSHA Legionella Guidance: The Occupational Safety and Health Administration (OSHA) has issued guidance on Legionella prevention and control in the workplace, particularly for healthcare facilities.

Adhering to these guidelines and staying up-to-date with any evolving regulatory requirements is essential for ensuring the safety and compliance of commercial water heater systems.

Emerging Trends and Technologies

As the industry continues to grapple with the challenges of Legionella control, new technologies and best practices are emerging to enhance the safety and efficiency of commercial water heater systems.

Ultraviolet (UV) Disinfection: The use of UV light to disinfect water and kill pathogens, including Legionella, is gaining traction in commercial water heater systems. UV systems can be installed as a supplemental treatment step to provide an additional layer of protection against Legionella.

Copper-Silver Ionization: This technology uses a low-level electric current to release copper and silver ions into the water, which can effectively neutralize Legionella and other microorganisms. It’s a chemical-free alternative to traditional disinfection methods.

Thermal Disinfection: Some facilities are exploring the use of periodic thermal disinfection, where the water heater temperature is raised to a high level (typically 140°F or higher) for a set duration to kill off Legionella and other pathogens.

Plumbing System Redesign: In some cases, comprehensive plumbing system redesigns may be necessary to address complex Legionella issues, such as eliminating dead-legs, improving water circulation, and utilizing more Legionella-resistant materials.

As water heater specialists, staying informed about these emerging technologies and best practices can help you provide your commercial clients with the most effective and up-to-date solutions for Legionella control.

Conclusion

Ensuring the safety and reliability of commercial water heater systems is a critical responsibility, and effectively managing the risks posed by Legionella is a crucial part of that duty. By understanding the science behind Legionella, implementing comprehensive preventive measures, and maintaining a vigilant monitoring and maintenance program, water heater specialists can help safeguard the health and well-being of building occupants and the public at large. ​ As the industry continues to evolve, staying informed about the latest regulatory guidance, industry best practices, and emerging technologies will be essential for navigating the murky waters of Legionella control in commercial water heater systems.

Tip: Consider upgrading to a tankless water heater for energy savings