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How to Improve Response to Legionnaires’ Disease Outbreaks and Conserve Water

March 9, 2020
NSF Health Sciences and Urban Sustainability Directors Network report recommends electronic cooling tower registry to help public health investigators quickly pinpoint the source of outbreaks

ANN ARBOR, MI, March 09, 2020 (GLOBE NEWSWIRE) -- A new policy report, Electronic Registration Systems for Cooling Towers – Improving Public Health and Sustainability Outcomes, published by the Urban Sustainability Directors Network (USDN) proposes a standardized yet flexible template for cooling tower registries that are designed to improve health outcomes, address disparity in affected populations, and increase water and energy efficiency.

NSF Health Sciences LLC, an NSF International company, and GroveWare Technologies developed the report for USDN with workshop input from more than 20 federal, state, provincial, city health, environmental, sustainability, water and/or building agencies.

Cooling towers are the point where heat extracted from a building is dissipated to the atmosphere through an evaporative process. As such, they are a critical component of many cooling systems in commercial, industrial, health care, hospitality and residential facilities. There are more than two million cooling towers in the United States, making them more common than elevators, yet much less regulated, according to the report.

Poorly maintained cooling towers can disperse Legionella through contaminated water droplets that are created as part of the cooling process. Once inhaled, the bacteria can cause Legionnaires’ disease, an acute form of pneumonia, and the less severe Pontiac fever. According to a study published in April 2018 in Current Environmental Health Reports, cooling towers were implicated or suspected in the majority of Legionnaires’ disease outbreak-associated deaths examined during the study period between 2006-2017.

With Legionnaires’ disease at a record high, the report argues that cities, states and water utilities should create electronic cooling tower registration systems to improve surveillance and response to cases, as well as to prevent exposure to Legionella bacteria by encouraging proper maintenance of cooling towers.

Additionally, since poor energy conservation practices increase water demand on buildings, registries are an important sustainability tool that can help evaluate the effectiveness of maintenance plans and identify areas for improved efficiency, the report highlights.

The U.S. Centers for Disease Control and Prevention (CDC) reported a record number of 9,933 Legionnaires’ cases in 2018, a more than eightfold increase since 2000. The National Academies of Sciences, Engineering, and Medicine (NASEM) in a 2019 report estimated as many as 70,000 people per year in the United States alone may suffer from the disease, and recommended adoption of cooling tower registries to help prevent or to rapidly respond to outbreaks. Response time is critical in an outbreak and proactively knowing the locations of cooling towers can help public health investigators pinpoint the source for remediation.

According to the CDC, one in 10 cases is fatal, and 90% of the outbreaks are preventable.

“Establishing a cooling tower registry is the crucial first step to dramatically improve the ability to meet public health and sustainability goals. This touch-stone document provides the scientific basis for creating cooling tower registries and the road map to ensure their successful implementation,” said Chris Boyd, General Manager of Building Water Health at NSF Health Sciences.

Most North American cities do not track the location of cooling towers and are “forced to rely on imprecise methodologies during public health emergencies,” the report says, adding that there is a “continued tolerance of widely divergent maintenance practices by building owners.”

“Cooling tower registries are a demonstrably effective and proactive tool for improving public health and fulfilling water efficiency goals,” said Patrick Ryan, M.Sc., P.Eng., Chief Building Official from Vancouver (Canada), a key participant city in the new report.

According to the report, registries provide municipalities with a management tool for maintenance record-keeping and support to building owners to meet regulations.

“The City of Vancouver is a true leader in North America in advancing public health measures in urban water systems. The uptake of this work is incredible to watch, proving the need for resources to support city inventory of cooling towers to prevent Legionella outbreaks. USDN is pleased to have been able to provide support for such an important effort,” said Nils Moe, USDN Executive Director.

New York City was the first U.S. city to create an electronic cooling tower registry system after a large outbreak in 2015 that sickened 138 people and led to 16 deaths. A handful of other cities and states, including Austin, TX; Hamilton, Canada; Vancouver, Canada; the State of New York; Quebec, Canada; and Victoria, Australia, now require cooling towers to be registered. National registries also exist in the United Kingdom, France, Germany, the Netherlands, Hong Kong and Singapore.

The report details IT specifications to create and rapidly implement an electronic cooling tower registration system.

“Technology plays a key role in nurturing a healthy urban living environment. The USDN workshop provided us the opportunity to share our experience deploying the New York City Registration Portal with participating governments and provided attendees with a roadmap for a successful program implementation,” said Hrair Achkarian, President and CEO of GroveWare Technologies Inc., the software firm that developed New York City’s cooling tower registration system.

Registries can also be a crucial tool to measure key sustainability performance indicators, aiding jurisdictions in evaluating the effectiveness of a building’s water conservation plans and identifying areas for improved energy efficiency. (Below, an illustration from the report.)

Cooling towers can be a significant source of water demand for a building, representing 20-50% of total water usage, according to the report, which added that poor management practices result in millions of wasted gallons of water per year in a single cooling tower. In Los Angeles alone, for example, it is estimated that more than two billion gallons of water per year are wasted, according to the report. 

The report reflects information collected from participants in webinars on April 15, May 17 and July 16, 2019; as well as a two-day workshop conducted Sept. 9-10, 2019, at the annual Legionella Conference in Los Angeles co-hosted by NSF Health Sciences and the National Environmental Health Association. NSF and GroveWare also conducted interviews with several agencies participating in the USDN project to gain insight into what criteria and factors were critical to their public health and sustainability missions.

NSF Health Sciences is presenting the findings of the report at upcoming events, including the AWWA Sustainability Conference in March 2020 in Minneapolis, AWWA ACE in June 2020 in Orlando and the National Environmental Health Association annual meeting in July 2020 in New York City. Public agencies interested in receiving a training/workshop on cooling tower registration systems, Legionnaires’ disease outbreak response investigations and/or sustainability strategies for cooling tower systems should contact NSF Health Sciences LLC’s building water health team at +1.734.769.8010. Read the report with a full list of participant cities at USDN and NSF


NSF International celebrated 75 years of protecting and improving human health. The global public health organization facilitates standards development, and tests and certifies products for the food, water, health sciences and consumer goods industries to minimize adverse health effects and protect the environment. Founded in 1944, NSF is committed to protecting human health and safety worldwide. With operations in 180 countries, NSF International is a Pan American Health Organization/World Health Organization (WHO) Collaborating Center on Food Safety, Water Quality and Indoor Environment. NSF Health Sciences is an NSF International company, organizing educational conferences and providing building water health services. NSF Health Sciences and the National Environmental Health Association are co-hosting Legionella Conference 2020 to bring together public health leaders, policy makers, researchers, practitioners and water management systems experts to discuss policies and strategies for the prevention of health care-associated waterborne disease outbreaks, including hazards related to medical devices, cleaning and disinfection in sterile settings, and water quality requirements in hospitals and health care facilities.

Fran LeFort, NSF International, +1.734.773.4253, [email protected].