Controlling Legionella pneumophila in Water Systems at Reduced Hot Water Temperatures with Copper and Silver Ionization

ELAINE CLOUTMAN-GREEN, VERA L BARBOSA, DIEGO JIMENEZ, DANIEL WONG, HELEN DUNN, BRIAN NEEDHAM, LENA CIRIC, JOHN C HARTLEY
ELSEVIER, AMERICAN JOURNAL OF INFECTION CONTROL, JANUARY 2019

Introduction
This study was conducted at a newly built healthcare facility in the United Kingdom. There, the Department of Health recommends maintaining hot water temperatures above 131^o F (55^o C) to control Legionella in water supply systems. 

The goal of this study was to determine the efficacy of copper-silver ionization to control Legionella at deliberately reduced hot water temperatures in a newly-constructed healthcare facility.

Results
The results of routine monthly sampling (1,598 total) from 2011 to 2017 demonstrated effective (100%) Legionella control with an average hot water temperature of 107.6°F (42°C). The facility experienced a 33% reduction in energy usage and a 24% reduction in carbon emissions.

Conclusion
This study showed that the spread of Legionella could be controlled at reduced hot water temperatures, but interventions were required to maintain adequate levels of copper and silver.