Healthcare Water Management Program Frequently Asked Questions

Legionnaires’ disease and other infections associated with building water systems

  1. Why are healthcare facilities at higher risk for having Legionnaires’ disease cases and outbreaks than other types of buildings?
    Healthcare facilities, such as hospitals and nursing homes, usually serve the populations at highest risk for Legionnaires’ disease. These include older people and those who have certain risk factors, such as being a current or former smoker, having a chronic disease, or having a weakened immune system. Also, healthcare facilities can have large complex water systems that promote Legionella (the bacterium that causes Legionnaires’ disease) growth if not properly maintained. For these reasons, the Centers for Medicare & Medicaid Services (CMS) and the Centers for Disease Control and Prevention (CDC) consider it essential that hospitals and nursing homes have a water management program that is effective in limiting Legionella and other opportunistic pathogens of premise plumbing (waterborne pathogens, for short)  from growing and spreading in their facility.
  2. What are “opportunistic pathogens of premise plumbing” and what are some examples other than Legionella?
    Opportunistic pathogens of premise plumbing are germs that grow well in drinking water distribution systems and can cause disease in humans. Examples of these include Pseudomonas, Acinetobacter, Burkholderia, Stenotrophomonas, nontuberculous mycobacteria, various species of fungi, and Naegleria fowleri. Many of the environmental factors that are conducive for Legionella growth also allow for growth of these other opportunistic pathogens.
  3. How do Legionella and other opportunistic pathogens of premise plumbing get into building water systems?
    Legionella and other waterborne pathogens occur naturally in the environment, in bodies of water like lakes, rivers, and streams. Although municipalities treat their water with disinfectants like chlorine that can kill these pathogens, a number of factors may allow these pathogens to enter a building’s water distribution system, such as
    • Construction (including renovations and installation of new equipment): Vibrations and changes in water pressure can dislodge biofilm and release Legionella or other waterborne pathogens. Biofilm is a slimy layer in pipes in which pathogens can live; it can give pathogens a safe harbor from disinfectants.
    • Water main breaks: Changes in water pressure can dislodge biofilm and release Legionella or other waterborne pathogens. In addition, water main breaks can introduce dirt and other materials into the water that use up all of the available disinfectant.
    • Changes in municipal water quality: Changes in water quality can increase sediment, lower disinfectant levels, increase turbidity, or cause pH to be outside recommended ranges. Also, if a supplier changes the type of disinfectant it uses, this change can impact how the water management program team should monitor its building water systems.

    In addition, factors within building water systems can promote Legionella growth, including

    • Biofilm, scale, and sediment
    • Fluctuations in water temperature and pH
    • Inadequate levels of disinfectant
    • Changes in water pressure
    • Water stagnation

Water Management / Sampling

  1. What is a water management program? Water management programs identify hazardous conditions and take steps to minimize the growth and spread of Legionella and other waterborne pathogens in building water systems. Developing and maintaining a water management program is a multi-step process that requires continuous review. Seven key activities are routinely performed in a Legionella water management program:
    1. Establish a water management program team
    2. Describe the building water systems using flow diagrams and a written description
    3. Identify areas where Legionella could grow and spread
    4. Decide where control measures should be applied and how to monitor them
    5. Establish ways to intervene when control limits are not met
    6. Make sure the program is running as designed (verification) and is effective (validation)
    7. Document and communicate all the activities

    In general, the principles of effective water management include

    • Maintaining water temperatures outside the ideal range for Legionella growth (77–113°F)
    • Preventing water stagnation
    • Ensuring adequate disinfection
    • Maintaining premise plumbing, equipment, and fixtures to prevent sediment, scale, corrosion, and biofilm, all of which provide a habitat and nutrients for Legionella

    Members of a building water management program team work together to

    • Identify ways to minimize growth and spread of Legionella and other waterborne pathogens
    • Conduct routine checks of control measures to monitor areas at risk
    • Take corrective action if a problem is found

    Once established, water management programs require regular monitoring of key areas for potentially hazardous conditions. Programs should include predetermined responses to correct hazardous conditions if the team detects them.

    Learn more about developing a water management program.

  2. Is routine sampling for Legionella recommended to validate a water management program at a healthcare facility?
    Sometimes. The water management program team should regularly monitor water quality parameters, such as disinfectant and temperature levels. By monitoring these parameters, the team can ensure that building water systems are operating in a way to minimize hazardous conditions that could encourage Legionella and other waterborne pathogens to grow. However, it is up to the team to determine how to validate the efficacy of the program, based on the environmental assessment* and data supporting the overall performance of the water management program. According to the CDC/Healthcare Infection Control Practices Advisory Committee (HICPAC) Guidelines for Environmental Infection Control in Health-Care Facilities [241 pages, 2.31 MB] and Guidelines for Preventing Health-care-associated Pneumonia [179 pages], as well as to ANSI/ASHRAE Standard 188–2018, one option for validating the efficacy of the program is to perform environmental sampling for the hazard, in this case Legionella. Sampling for Legionella may be an appropriate way to confirm that a water management program, when implemented as designed, effectively controls the hazardous conditions throughout the building water systems that lead to Legionella growth. Additional guidance for Legionella prevention for facilities with protective environments (i.e., transplant units) is included in the HICPAC guidelines. If the team decides to perform validation using environmental sampling for Legionella or other waterborne pathogens, it should not be performed in isolation but rather as part of a comprehensive water management program. Specific decisions about sampling frequency, location, and methodology are made by the team. Sampling plans are unique to each facility and are based on factors such as
    • Findings from the environmental assessment and any baseline Legionella test results
    • Overall performance of the water management program, trend analysis of Legionella test results, and water quality parameters (e.g., disinfectant, temperature)
    • In healthcare facilities, correlation of environmental test results with clinical surveillance data
    • Building characteristics (e.g., size, age, complexity, populations served)
    • Sites of possible exposure to aerosolized water
    • Available resources and supplies to support testing

    *The environmental assessment enables the water management program team to gain a thorough understanding of a facility’s water systems and assists facility management with minimizing the risk of legionellosis. Guidance is available via CDC’s Legionella Environmental Assessment Form [15 pages].

  3. What specific information is available regarding monitoring parameters and control measures (e.g., temperatures, disinfectant levels)?
    Guidance on monitoring is available, but the specifics for each building will be defined by the water management program team, taking state and local regulations into consideration, as well as a variety of factors including the facility environmental assessment, manufacturer’s operating instructions, and the data supporting the overall performance of the water management program. ASHRAE Guideline 12 may be most helpful.
  4. Can you provide an example of a water management program?
    The CDC toolkit Developing a Water Management Program to Reduce Legionella Growth & Spread in Buildings [36 pages, 13.30 MB] walks through the key elements of a comprehensive water management program and describes the steps involved in creating and maintaining the program. Every building is different (depending on factors such as the structure, age, location, occupants of the building, or surrounding conditions), so each one needs a tailored program. The details will be defined by the water management program team, taking state and local regulations into consideration. The Preventing Legionnaires’ Disease Training created by CDC and partners outlines how to reduce risk for Legionella in facilities. This online training leads participants through the steps for developing and implementing a water management program. Learn more about implementing a water management program.

References and Resources


Guidelines and Requirements

Planning Guides and Toolkits

Healthcare Resources


Literature Reviews