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

Introduction
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.

Results
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.

Conclusion
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.