Peer-Reviewed Research Study

Examining the Efficacy of Copper-Silver Ionization for Management of Legionella

Mark LeChevallier
American Water Works Association (AWWA), Water Science, March 2023

This review article examined more than 80 sources of literature and studies related to copper-silver ionization system efficacy, design, maintenance, and operations, and the impact water chemistry has on its performance.

Previous research indicates that copper-silver ionization is effective for Legionella control. Other key findings of this study include:

  • Copper and silver can work as biocides independently or together.
  • The EPA recognizes both copper and silver as metallic antimicrobial agents.
  • Copper-silver ionization is effective against various waterborne pathogens, including Legionella, Nontuberculous Mycobacterium, Pseudomonas, Stenotrophomonas, Acinetobacter, and fungi.
  • There is no evidence of copper-silver resistance occurring with Legionella.
  • Factors that should be considered during planning, commissioning, and system operation include temperature, oxygen levels in the water, flow, pH levels, biofilm, sediment, and other chemicals.
  • Case studies reviewed show positive results for general hospitals, specialty hospitals, children’s hospitals, veterans’ hospitals, multi-family buildings, and hotels.

The report concludes that using copper-silver ionization to control Legionella and other opportunistic pathogens is highly effective when the units are properly designed, maintained, and operated.

Related studies

Hospitalizations Due to Selected Infections Caused by Opportunistic Premise Plumbing Pathogens and Reported Drug Resistance in the United States Older Adult Population

Controlling Legionella in Hospital Drinking Water: An Evidence-Based Review of Disinfection Methods

Intermittent Use of Copper-Silver Ionization for Legionella Control in Water Distribution Systems: A Potential Option in Buildings Housing Individuals at Low Risk of Infection

Highlighted author

Dr. Mark LeChevallier

Dr. Mark LeChevallier is a drinking water research scientist with a PhD in Microbiology. In addition to authoring or coauthoring more than 150 journal publications, contributing to more than 70 reports or book chapters, and presenting at more than 100 conference proceedings on water-related pathogen issues, Dr. LeChevallier is a member of the Drinking Water Subcommittee of the Science Advisory Board of the United States Environmental Protection Agency, a past member of the Water Science Technology Board of the National Academies of Science, and the past Chair of the American Water Works Association Water Science & Research Division.

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