Key points
- Water management programs (WMPs) can effectively limit growth and spread of certain pathogens in water systems.
- The first two sections below address infections associated with building water systems.
- The next three sections address water management and sampling.
- The last section addresses healthcare facilities and the unique challenges they face.
Opportunistic pathogens of premise plumbing
Opportunistic pathogens of premise plumbing are germs that grow well in drinking water distribution systems (also called waterborne pathogens). They also can cause disease in humans.
Legionella is the bacterium that causes Legionnaires' disease, a type of pneumonia. Other examples include:
- Acinetobacter
- Burkholderia
- Naegleria fowleri
- Nontuberculous mycobacteria
- Pseudomonas
- Stenotrophomonas
- Various species of fungi
Many of the environmental factors that are conducive for Legionella growth also allow for growth of these other opportunistic pathogens.
Pathogen introduction and growth in water systems
Legionella and other waterborne pathogens occur naturally in the environment, in bodies of freshwater like lakes, rivers, and streams.
Factors that allow introduction
Water providers typically treat their water with disinfectants like chlorine that can kill the pathogens. However, a number of factors may allow these pathogens to enter a building's water distribution system.
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 available disinfectant.
Changes in municipal water quality
Changes in water quality can
- Increase sediment
- Increase turbidity
- Lower disinfectant levels
- Cause pH to be outside recommended ranges for the disinfectant
Note: A supplier changing the disinfectant type it uses can impact how the WMP team should monitor its building water systems.
Factors that allow growth
Factors within building water systems can promote growth of any waterborne pathogen in the water. These factors include:
- Biofilm, scale, and sediment
- Fluctuations in water temperature and pH
- Inadequate levels of disinfectant
- Water stagnation
Water management programs
WMPs identify hazardous conditions and take steps to minimize the growth and spread of waterborne pathogens in building water systems. Developing and maintaining a WMP is a multi-step process that requires continuous review.
Members of a building WMP team work together to
- Identify ways to minimize growth and spread of waterborne pathogens
- Conduct routine checks of control measures to monitor areas at risk
- Take corrective action if a problem is found
- Verify that a WMP is working as intended
Once established, WMPs require regular monitoring of key areas for potentially hazardous conditions. Programs should include predetermined responses to correct hazardous conditions if the team detects them.
Get easy-to-understand guidance from CDC
Parameters and control measures guidance
Guidance on monitoring water parameters is available.
Tailored strategy recommended
The water monitoring specifics for each building will be defined by the WMP team. The team considers a variety of factors, including:
- Data supporting the overall performance of the WMP
- Findings from a facility-specific environmental assessment
- Manufacturer operating instructions for specific devices
- State and local regulations
The Legionella Control Toolkit provides guidance on WMP control measures and water quality parameter limits.
WMP templates and other resources
The Council of State and Territorial Epidemiologists provides a WMP template and other helpful resources.
CDC's WMP toolkit
- Describes the steps involved in creating and maintaining the program
- Walks through the key elements of a comprehensive WMP
Every building is different, so each one needs a tailored program. The details will be defined by the WMP team, taking state and local regulations into consideration.
Want training on WMPs?
Risk in healthcare settings
Healthcare facilities usually serve the populations at highest risk for Legionnaires' disease. Also, healthcare facilities can have large complex water systems that promote Legionella growth if not properly maintained. Healthcare facilities include hospitals, critical-access hospitals, and long-term care facilities.
Risk factors
People at increased risk for Legionnaires' disease include those who
- Are 65 years and older
- Are a current or former smoker
- Have a chronic disease
- Have a weakened immune system
Special requirements for healthcare facilities
For the above reasons, the Centers for Medicare & Medicaid Services requires and CDC recommends certain healthcare facilities have a WMP. The WMP should effectively limit growth and spread of opportunistic pathogens of premise plumbing, including Legionella.
Resources
Guidelines, standards, and requirements
General
ASHRAE
Guideline 12 [Free read-only preview]
Standard 188 [Free read-only preview]
CDC
Cooling Technology Institute
Healthcare-specific
CMS
CDC
Guidelines for environmental infection control in health-care facilities
Guidelines for infection control in dental health-care settings
Guidelines for preventing health-care-associated pneumonia
Department of Veterans Affairs
Prevention of healthcare-associated Legionella disease and scald injury from water systems
Infectious Diseases Society of America and the American Thoracic Society
Consensus guidelines on the management of community-acquired pneumonia in adults
Management of adults with hospital-acquired and ventilator-associated pneumonia
Laws
Literature reviews
Technologies for Legionella control in premise plumbing
Planning guides, toolkits, and trainings
Controlling Legionella in common sources of exposure
Developing a water management program to reduce Legionella growth and spread in buildings
Drinking water advisory communication toolbox
Emergency water supply planning guide for hospitals and healthcare facilities