August 15, 2019

New Report Urges Action to Manage Legionella in Water Systems

A new report published yesterday by the National Academies of Sciences, Engineering, and Medicine calls for a range of actions to prevent the growth of Legionella in water systems. The report focuses on the ecology and diagnosis of Legionella contamination of water systems, strategies for the control of Legionella, and regulations and guidelines on Legionella control in water systems. Inhaling air contaminated with Legionella bacteria from water systems can cause Legionnaires’ disease, a serious type of pneumonia, or Pontiac fever, a milder flu-like illness. The report states that Legionnaires’ disease afflicts and kills more people in the United States than any other reported waterborne disease. The Committee on Management of Legionella in Water Systems, which developed the publication, estimates that the number of people in the U.S. who get Legionnaires’ disease each year ranges from 52,000 to 70,000. This incidence rate is approximately 10 times higher than the number of reported cases, which the committee says does not capture everyone who contracts the disease.

In an online briefing to introduce the new report, members of the committee explained that multiple factors likely contribute to the increasing incidence of Legionnaires’ disease in the U.S. These factors include an increasing number of people with health vulnerabilities, aging water infrastructure in cities, more complex water features, unintended consequences related to green buildings (such as lower hot-water temperatures in plumbing), and changing environmental conditions, including global warming.

The new report stresses that more comprehensive policy for Legionella management is needed in the U.S., where regulations currently cover only healthcare facilities in the state of New York, cooling towers in New York and New York City, healthcare facilities within the Veterans Health Administration, and hospitals and healthcare facilities that receive Medicare or Medicaid funds. According to the authors, the federal Safe Drinking Water Act does not provide any substantial control of Legionella in water systems, and many buildings and private residences are formally protected from Legionella only by building and plumbing codes.

The report outlines several ways to improve regulations related to Legionella management in the U.S. Recommendations include implementing regulations and guidelines that require the registration and monitoring of cooling towers and requiring water management plans in all public buildings. The committee also suggests expanding federal requirements of the Centers for Medicare and Medicaid Services that apply to hospitals and other healthcare facilities to require monitoring for Legionella in environmental water samples for all types of buildings.

The report urges other actions to prevent the growth of Legionella in water systems, including maintaining water temperature outside Legionella’s preferred growth range. Hot-water heater temperatures should be maintained above 140°F and the hot-water temperature to distal points should exceed 131°F, according to the report. In addition, low-flow fixtures should not be allowed in hospitals, long-term care facilities, and other buildings with high-risk occupant populations. The committee also recommends modifying criteria for certifying green buildings, energy-conserving features, and water conservation features to account for risk factors associated with the growth of Legionella in building water systems.

A recording of the report release briefing is available online. Presenters’ slides (PDF) have also been posted. The full report, “Management of Legionella in Water Systems,” is available as a free PDF download from the National Academies website.

Related: The AIHA guideline Recognition, Evaluation, and Control of Legionella in Building Water Systems, which is referenced by the National Academies report, is available for purchase in the AIHA Marketplace. An article in the June/July issue of The Synergist discussed Legionella regulations in New York.