How to Mitigate Legionella Outbreaks in Health Care Facilities

April 9, 2024

The health care industry assumes one of the most critical roles of all time — preserving human health, safety and quality of life. Hospitals, nursing homes and other medical facilities must assess this goal from all standpoints, including their water systems.

Health care facilities rely on numerous water sources every day, many of which are vulnerable to a potentially harmful bacteria called Legionella. Having the proper protocols in place is essential to reduce the growth and spread of this pathogen throughout your building.

This guide will cover the basics of Legionella, the importance of controlling this bacteria and how to keep it out of your medical facility’s water systems. 

What Is Legionella Bacteria?

Legionella pneumophila is a type of bacteria that grows in warm, humid climates. It can grow indoors or outdoors, often in the following settings:

  • Lakes
  • Rivers
  • Streams
  • Creeks
  • Ponds
  • Hot springs
  • Sink faucets
  • Showerheads
  • Decorative water walls and fountains
  • Cooling towers
  • Hot water tanks and heaters
  • Large plumbing systems
  • Hot tubs
  • Air washers

Water Conditions That Promote Legionella

Several factors can supply nutrients for Legionella or encourage its growth, including:

  • Stagnant water
  • Scale from mineral deposits
  • Temperatures between 68 and 122 degrees Fahrenheit
  • pH between 5 and 8.5
  • Suspended sediment particles in the water
  • The presence of microorganisms like protozoa, amoebae and algae

Legionella often grows in slime or biofilms on natural bodies of water. However, indoor water systems are also susceptible, making vigilant treatment and maintenance a must to control buildup.

Even low and nondetectable Legionella levels can colonize water systems, multiplying significantly under ideal conditions. Warm temperatures also make it difficult to keep disinfectants — such as chlorine — at optimal levels for killing Legionella.

How Does Legionella Enter Industrial Water Systems?

A few conditions can introduce Legionella into health care water systems. Here are a few examples to be aware of:

  • Construction projects: Biofilm is a slimy substance that often grows on pipes in industrial water systems. It houses Legionella and other waterborne pathogens, protecting them from disinfectants. Construction modifications, renovations and equipment installations in health care facilities can cause changes in water pressure. These vibrations can dislodge biofilm, allowing Legionella and other bacteria to enter water systems.
  • Water main breaks: Water main breaks can introduce dirt and other contaminants into water systems. They can cause Legionella to enter the water supply, even if there was no previous evidence of this bacteria. When flushing and treating water after repairing a water main break, a professional water treatment provider can offer advice on eliminating Legionella from your system.
  • Municipal water quality changes: Fluctuations in surrounding water quality can reduce disinfectant levels, increase sediment and turbidity, and throw pH levels off balance, increasing the risk of Legionella formation and spread. Additionally, say a supplier switches the type of disinfectant they use. This change can influence how a health care facility should monitor its water systems.
  • Insufficient disinfectant: Proper disinfectant procedures are essential to hinder Legionella in water systems. Chlorination is a go-to method for disinfecting process water and impeding Legionella growth. Improper disinfectant strategies — such as incorrectly measuring the chlorine-to-water ratio — can cause inadequate disinfectant levels that cannot fully remove the Legionella from the system. That’s why devising and following a disinfection plan is crucial.
  • Cross connections: Cross connections between potable and non-potable water can cause Legionella to enter the water system.
  • Improper corrosion prevention: Factors like water temperature, pH levels and types of disinfectants can cause water system pipes to corrode. Rust can act as a nutrient for Legionella bacteria, meaning higher corrosion levels in water systems increase its growth. Proper rust and corrosion control is a must for industrial water systems.

Health Risks Associated With Legionella

Generally, Legionella is harmless when present in soil and natural water systems. However, Legionella in poorly maintained industrial water systems can pose human health hazards.

Exposure to Legionella bacteria can cause Legionnaires’ disease, a serious lung infection that is a type of pneumonia. Early symptoms include low-grade fever, sore muscles, fatigue and loss of appetite. Later symptoms usually include:

  • A fever of 102-105 degrees Fahrenheit
  • Wet cough or hemoptysis
  • Breathing complications
  • Chills
  • Chest pain
  • Gastrointestinal symptoms like nausea, diarrhea, vomiting and abdominal pain

Legionella exposure can also lead to Pontiac Fever, a less severe infection with milder, flu-like symptoms, such as:

  • Low-grade fever
  • Appetite loss
  • Fatigue
  • Headaches
  • Muscle aches
  • Dry cough
  • Nausea
  • Chills

Collectively, Legionnaire’s disease and Pontiac Fever are known as Legionellosis.

How Does Legionellosis Spread?

Legionellosis does not spread from person to person, meaning it isn’t contagious. Rather, it transmits through the inhalation of microscopic, airborne water droplets contaminated with the bacteria. In rarer cases, people can contract the disease by drinking water or aspirating Legionella-contaminated soil.

While anyone can contract Legionellosis, the disease’s severity can depend on the person’s general health and physical condition. The source and degree of bacterial contamination also play a role. Globally, waterborne Legionella is the most prevalent cause of Legionellosis cases and outbreaks.

Who Is at Risk of Legionellosis?

The following groups have a higher likelihood of contracting Legionellosis following Legionella exposure:

  • People over the age of 50
  • People with chronic lung disease
  • Current and former smokers
  • Immunocompromised individuals
  • People with underlying medical conditions like cancer, diabetes, kidney disease and liver failure

In most cases, people without these conditions won’t get sick when exposed to Legionella. Those who contract Legionnaires’ disease typically need professional medical care but fully recover with treatment. Only about 10% of Legionnaires’ disease cases are fatal.

Sources and Risk Factors in Health Care Facilities

Health care facilities like hospitals and nursing homes are common settings for Legionella growth. They have a higher risk of Legionnaires’ disease outbreaks than other facilities for a couple of reasons:

1. High-Risk Populations

Nursing homes and hospitals accommodate people with an increased risk of Legionellosis, such as older individuals, people with chronic illnesses or those with weak immune systems. Naturally, health care facilities are more prone to Legionnaires’ disease outbreaks than other buildings.

2. Large, Complex Water Systems

Many health care facilities have extensive industrial water systems. Water is essential for various everyday activities in medical settings, including:

  • Laboratory testing procedures
  • Cleaning surgical devices (As of August 2023 there is new industry standard for this called the AAMI ST108
  • Laundry
  • Bathing and showering
  • Heating and cooling applications

Hospitals rely on multiple water sources, including cooling towers, water heaters, sinks and showers. Large and complex water systems are more likely to harbor growth conditions for Legionella — such as ideal pH and temperature ranges, microorganisms and stagnation — especially with a lack of regular water treatment and maintenance.

3. Inconsistent Water System Usage

Some of a medical facility’s water sources might see daily use, while others may see little to none. A lack of water use and flow can promote Legionella development due to stagnation. “Dead legs” — sections of pipework, taps and outlets with no water flow — heighten the risk of Legionella.

The Importance of Water Treatment Programs for Legionella

For the above reasons, the Centers for Disease Control and Prevention (CDC) advises hospitals and nursing homes to implement robust water management plans (WMPs). These programs aim to keep Legionella and other pathogens from infiltrating their water systems and causing outbreaks in health care facilities.

WMPs identify hazardous conditions that promote Legionella growth and then exercise the appropriate measures to mitigate spread and outbreaks. Your WMP should also outline a response plan in case a Legionella outbreak occurs in your facility. Creating and following a comprehensive WMP is a multi-step process requiring ongoing documentation, reporting and monitoring.

WMPs have become an industry standard in the United States, particularly for larger, multi-story buildings with extensive water systems. They outline practical steps for water system maintenance and bacteria control. Facilities that house older individuals and people with weakened immune systems are advised to have a WMP.

Customized WMPs by Chardon Laboratories

Chardon Labs can work with you to develop a robust WMP to control Legionella in your health care facility. Since 1965, we’ve served states throughout the Midwest and Mid-Atlantic regions with expert water treatment services.

If your building uses cooling towers, water heaters, central humidifiers or other water systems at risk of Legionella, we have the expertise, tools and resources to safeguard your facility from outbreaks. Our specialists can identify your facility’s risk areas and determine the proper control measures for each one. We’ll provide a risk analysis and customized WMP proposal for your building.

Our process encompasses the following steps:

  • Site analysis: One of our experts will survey your facility and pinpoint potential risk areas for Legionella bacteria. This initial assessment helps us determine the right control measures for your WMP.
  • Testing: Bacteria testing requirements and frequencies will depend on the risks associated with your facility. After analyzing your building, we’ll determine the proper testing protocols based on your site’s control locations. A Chardon Labs technician will test for Legionella and send the sample to a state-of-the-art laboratory for further analysis.
  • WMP development: The next step is creating and implementing your building’s WMP. Depending on your facility’s Legionella risk factors and water treatment requirements, this plan might involve chemical treatments, pH adjustments, cleaning and flushing services, or a combination of strategies.
  • Adjustment and remediation: Correcting and refining the plan is the final step of implementing a WMP. It’s important to monitor changes to your water systems, building staff and testing and treatment protocols to protect employees and patients from Legionella outbreaks. We make it easy to access, adjust and update your WMP as needed through our convenient online portal.

Ensuring Regulatory Compliance in Health Care Water Systems

To protect the health and safety of both employees and patients, health care facilities should comply with water system standards to mitigate Legionella. Here are some regulatory bodies with specific recommendations regarding Legionella control and preventative maintenance:

  • American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE): ASHRAE Standard 188 requires ongoing Legionella testing and response measures as part of a comprehensive WMP. Health care facilities are expected to uphold these guidelines. ASHRAE 188 does not have regulatory authority unless incorporated into local building codes. However, buildings with complex water systems are strongly recommended to follow these guidelines when developing a WMP. Additionally, many federal agencies reference these standards when mapping out control measures for Legionella.
  • CDC: The CDC uses ASHRAE standards as a guide to offer recommendations for evaluating hazards in your building and developing a WMP. Its toolkit provides health care facilities with actionable measures to control Legionella in common water sources, such as cooling towers and ornamental fountains.
  • Occupational Safety and Health Administration (OSHA): While OSHA does not have specific standards for Legionella,several of its regulations may apply to occupational exposure to this bacteria. These include standards for personal protective equipment, eye and face protection, respiratory protection, and hand and foot protection.
  • Centers for Medicare & Medicaid Services (CMS): CMS expects Medicare- and Medicaid-certified health care facilities to have ASHRAE-compliant WMPs in place to reduce Legionella growth and spread. Businesses that don’t demonstrate measures to mitigate Legionellosis outbreaks could receive citations for noncompliance.
  • The Joint Commission: The Joint Commission released a standard (EC.02.05.02) that went into effect in January 2022. EC.02.05.02 mandates that medical facilities have a WMP to reduce the risk of Legionella and other waterborne pathogens.
  • Local and state regulations: Your state or municipality may have specific guidelines surrounding Legionella control in health care facilities. It’s important to comply with state and local standards as well as federal regulations.

At Chardon Labs, we follow ASHRAE Standard 188 protocols to ensure the most precise Legionella control measures for your facility. That includes surveying your water systems for risk areas, helping you create a WMP based on these results and validating your plan’s outcomes.

You can count on Chardon for rigorous water system management programs that minimize Legionella growth and spread, as well as keep your business compliant with regulatory guidelines.

Water Treatment Products We Use

Technology plays a foundational role in monitoring your water systems for Legionella growth and documenting WMP outcomes. At Chardon Labs, we use state-of-the-art equipment to treat, maintain and surveil cooling towers for Legionella risk factors, such as scale, rust, improper temperature levels and pH imbalances. We also use proprietary chemical solutions to manage these conditions.

Here are some of the different products we use for treating and maintaining water systems:

  • Automation equipment: We use devices like chemical pumps, conductivity controllers and mini pulse timers to ensure proper chemical feed rates for your water system. This equipment displays real-time data to optimize cooling tower performance and water treatment schedules.
  • Monitoring and risk prevention equipment: We use special monitoring equipment to control issues like chemical overfeeding, underfeeding, scaling, corrosion and bacterial growth in cooling towers. This product line includes pH probes, flow switches, bleed solenoids and contact headwater meters.
  • Chemicals: Chemical treatments are vital to ensure efficient water systems and keep bacteria to a minimum. We use a variety of chemicals to manage common problems in cooling towers, including pre-treatment chemicals, corrosion and scale inhibitors, oxidizing biocides, and anti-foaming chemicals.

Contact Chardon Labs for Legionella Control and Preventative Maintenance Services

Chardon Labs combines several decades of water treatment expertise, customized chemical treatments and state-of-the-art monitoring technology. This ensures the most robust bacteria management services for our clients. We serve health care facilities and other industries with comprehensive Legionella mitigation solutions.

Our ISO 9000-certified technicians will work with you to develop a personalized WMP that:

  • Keeps harmful pathogens at bay.
  • Maintains cooling tower efficiency.
  • Reduces your water and energy costs as much as possible.

Learn more about our Legionella testing and control services and contact our team to get the process started.

Portrait of Matt Welsh, the co-president
Matt Welsh
Vice President, Water Consultant at Chardon Labs | Website | + posts

Matt Welsh is the Vice President and Water Consultant at Chardon Labs.  He helps consult a wide range of customers utilizing various methods of water treatment, from chemical to chemical-free approaches, large and small applications, and across a wide range of geographical influences.  With 20 years of water treatment experience, including a wide range of troubleshooting and service in potable water and non-potable HVAC and industrial applications, he is an expert in water treatment chemistry for cooling towers, boilers, and closed-loop systems.


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