What can you tell your customers
about reducing their risk fromLegionella pneumophila?
What you don’t know can hurt you!
Being unaware of the potential disease risk from Legionella pneumophila in building water in your facility is no longer an
excuse in a court of law—or in the court of public opinion.
The ANSI/ASHRAE Standard 188-2015, Legionellosis: Risk Management for Building Water Systems, is a definitive standard that details
the minimum legionellosis risk-management requirements of potable and nonpotable water systems in both new and existing buildings.
The standard provides guidance to owners and managers of human-occupied buildings (excluding single-family residential buildings)
as well as individuals and companies who design, construct, install, commission, operate, maintain, and service centralized building
water systems and components.1

You need a thorough and thoughtful watermanagement plan

Routine monitoring is the best way to ensure
your water management plan is effective

Based on the building’s water system features, the ANSI/ASHRAE
Standard 188-2015 establishes guidelines for water management
plans to help manage the risk of legionellosis.2 Water management
plans must be tailored to each facility and must include thoroughdescription and analysis of the building water systems, control
measures, monitoring and plans for corrective action, as well as
confirmation and documentation, all provided by professionals
with the requisite experience. The CDC toolkit Developing a Water
Management Program to Reduce Legionella Growth & Spread in
Buildings: A Practical Guide to Implementing Industry Standards
provides a very useful overview to what a water management planshould include and how to approach developing one, including
specific recommendations for healthcare facilities.

Routine testing is an essential part of measuring whether awater management plan is effectively controlling a building’s
risk for a Legionnaires’ disease outbreak. Accurate and reliable
quantitative test results are required to understand where there
are the greatest risks in your water system so they can bereduced. It’s important to understand both the concentration ofL. pneumophila at a given point in the system and percentageof L. pneumophila-positive outlets throughout the system togauge risk, ensure control measures are working, and take any
remediation steps needed. This monitoring should be done
over time to detect any increases in L. pneumophila, including
increases that result from changes to the system, such asconstruction, water pressure changes, or water main breaks.
L. pneumophila is virtually impossible to completely eradicate
in complex water systems, but it can be effectively controlled
through proper monitoring and control measures.

Focus on reducing risk from the primary cause of
Legionnaires’ disease, Legionella pneumophila
Focusing detection and control efforts on Legionella pneumophila,
the primary causative agent of Legionnaires’ disease, can increase
the efficiency and efficacy of your water management plan.
L. pneumophila is the most common and clinically relevant speciesof Legionella. It thrives in low-nutrient conditions and grows asbiofilms on the inner surfaces of pipes. Biofilms allow thesepathogens to resist disinfectants and environmental stressors,
and aid in the spread of antibiotic resistance and virulence genes.
Water management plans that include measures to address these
conditions and effectively control L. pneumophila will also control
other species of Legionella at the same time. This focus may help
building owners avoid the costs and dangers of unnecessary
shutdowns and/or treatment triggered by the detection ofLegionella species that are far less virulent than L. pneumophila.

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References
1. ASHRAE. Legionellosis: Risk Management for Building Water Systems.
Atlanta, GA: American Society of Heating, Refrigerating and
Air-Conditioning Engineers; 2015:2. ANSI/ASHRAE Standard 188-2015.
2. ASHRAE. Legionellosis: Risk Management for Building Water Systems.
Atlanta, GA: American Society of Heating, Refrigerating and
Air-Conditioning Engineers; 2015:5. ANSI/ASHRAE Standard 188-2015.