Overview of Water Management Programs

Water management programs identify hazardous conditions and take steps to minimize the growth and transmission 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. Such programs are now an industry standard for many buildings in the United States.

Key Elements

Seven key elements of a Legionella water management program are to:

  • Establish a water management program team
  • Describe the building water systems using text and flow diagrams
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  • Identify areas where Legionella could grow and spread
  • Decide where control measures should be applied and how to monitor them
  • Establish ways to intervene when control limits are not met
  • Make sure the program is running as designed (verification) and is effective (validation)
  • 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
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  • Preventing water stagnation
  • Ensuring adequate disinfection
  • Maintaining devices to prevent sediment, scale, corrosion, and biofilm, all of which provide a habitat and nutrients for Legionella

Once established, water management programs require regular monitoring of key areas for potentially hazardous conditions and the use of predetermined responses to respond when control measures are not met.

Building Factors

Each program has to be tailored for each particular building at a particular point in time. Building factors to take into consideration include:

  • Structure and size
  • Age
  • Location and surrounding conditions
  • Unique areas of risk for Legionella growth and spread
  • Whether the buildings are intended for use by people at increased risk for Legionnaires’ disease

Options may vary depending upon state and local building codes, water treatment regulations, healthcare accreditation and survey requirements, and public health reporting requirements. For example, anti-scald regulations may limit maximum allowable water temperatures.

In some settings, such as hospitals and other large buildings with complex water systems, you need a water management program for the entire building. In other settings, such as small buildings with simple water systems, you may only need a water management program to cover the devices that aerosolize water. Examples of these devices include fountains, hot tubs, cooling towers, and respiratory equipment intended for nebulization.


You can use this worksheet to identify buildings and devices at increased risk for Legionella growth and spread that should have a water management program according to industry standards (ASHRAE Standard 188).

In 2016, CDC released a toolkit to provide practical guidance on developing a water management program. This includes how to implement industry standards by identifying areas or devices in buildings where Legionella might grow or spread to people. You can also find guidance specific to healthcare facilities in this toolkit.

A consultant with Legionella-specific environmental expertise may sometimes be helpful in implementing and operating water management programs.