Protecting Your Business From Legionella

Whatever the industry, your business likely uses water on a daily basis. Hot water heaters, drinking water systems, humidifiers, hot tubs, and outdoor fountains all help create a comfortable environment for both your customers and your employees. However, if the water in these systems becomes contaminated with the harmful waterborne bacteria Legionella pneumophila, your employees, clients, and business can be put at serious risk. In addition to posing liability risk, a Legionnaires’ disease outbreak can be damaging financially and to your reputation.

When Legionella bacteria contaminate water sources and are inhaled through a vapor or mist, they can cause legionellosis, which can take form as either Legionnaires’ disease or the less severe Pontiac fever. Symptoms begin soon after exposure and include high fever, headaches, chills, and cough. Antibiotics are usually successful in treating the disease, but hospitalization is commonly required. The Centers for Disease Control and Prevention report that between 8,000 and 18,000 people are hospitalized with Legionnaires’ disease yearly in the United States.[1]

To help prevent a Legionella outbreak, it’s important to establish a formal, written air-handling (HVAC) and water system maintenance program that includes the following elements:

Test and inspect air-handling and water distribution systems.

Regularly examine your HVAC system’s air-handling units for accumulated, pooling water and excess condensation. Keep decorative fountains and water walls running with treated water and/or disinfectants, and frequently check swimming pool water circulation and chemical levels. The purpose of testing all water systems is to verify the effectiveness of the water treatment protocols. Even if a vendor monitors chemical levels remotely, you need an annual inspection of the dispensing and calibration system and in-house water chemical testing and recordkeeping. For hot water systems, be sure to also conduct regular tests to confirm that the water temperature at the source and at the end of the distribution system is adequate. For example, hot water heaters should be maintained at 140 degrees. Consider contracting with an outside laboratory to complete regular water tests.

Maintain formal water temperature and testing logs.

Document all tests conducted both in-house and through a vendor, including temperature results and chemical details (e.g., chlorine/bromine levels in pools, cooling tower water disinfectant levels). Keep these logs current and update them regularly.

Document chemical use.

Maintain documentation on the types (e.g., biocides, disinfectants), amounts, and dates of when chemicals are added to each system. Obtain material safety data sheets for each chemical, and train workers on chemical storage, use, and disposal.

Establish cleaning and disinfecting schedules.

Establish and monitor the procedures used by housekeeping employees or contracted services to maintain common areas, restrooms, decorative fountains, and other areas. Document the chemicals used, their dilutions, and frequency of use.

Have a maintenance backup plan.

In the event the individual responsible for your maintenance program is unavailable, have a plan in place so that other qualified persons can quickly take over. Consider cross-training your in-house maintenance staff or contracting with external vendors with this expertise.

Maintain manuals and resources.

Keep all equipment manuals, installation diagrams, and other important information up to date. For example, videotape interviews with system component vendors in which they explain component features, what to look for and document during self-inspections, and preventive maintenance schedules. If necessary, your qualified staff can review the manuals and watch the videos to get up to speed.

Establish corrective protocols if Legionella bacteria are detected.

Implement and document your remediation efforts. For example, superheating hot water to keep temperatures above 140 degrees, flushing all water taps, disinfecting showerheads and faucets, hyper-chlorinating cooling towers, and cleaning/sanitizing all filters may all be effective.

Formulate vendor protocols and processes.

If a vendor performs your building maintenance, prominently display and make available all contact numbers and service dates/logs. Building management should meet with the vendor at least annually to review all services. If maintenance is performed in-house, management should regularly review all services with their staff.

If a vendor performs air-handling and water system maintenance, cleaning, and testing, your legal staff should review the contracts for risk transfer and insurance requirements.

By following these and other best practices, as well as consistently monitoring your cleaning and maintenance processes, you can help minimize your workers’ and visitors’ exposure to Legionella.


[1]Centers for Disease Control and Prevention, “Legionnaires’ Disease.”

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The illustrations, instructions, and principles in this material are general in scope and, to the best of our knowledge, current at the time of publication. No attempt has been made to interpret any referenced codes, standards, or regulations nor to identify all potential risks or requirements.