Ice Machines- An under-appreciated source of Legionella

Ice Machines have been getting more scrutiny lately due to updates to water hygiene standards for Hospitals, Nursing homes, and any business that services the elderly and immuno-compromised. That’s good, because Ice Machines are dirtier than you might think.

That may seem counter intuitive. After all, they’ve typically got filters to remove impurities, they are cold (Can Legionella survive in ice?) and how often do people breathe in ice?  Yet, there are outbreaks of ice machine borne Legionella worldwide among susceptible populations. A casual google search for “Legionella Ice Machine” on any given day will turn up thousands of articles and news stories about Legionella outbreaks.

In July 2018, an outbreak affecting two residents at St. John’s Fountain Lake senior community in Albert Lea, MN was reported. Residents were warned specifically not to use the Ice Machines.

This blog is written to question casual assumption people outside of Infection Control might harbor (If you need more technical information you can find it at the end of this blog):

Doesn’t the temperature of the Ice Machine control Legionella? – The ice machine compressor generates heat as it creates water from ice. Any water stored in the ice machine may be heated to temperatures which are perfect to grow Legionella and other pathogens. Freezing Legionella contaminated water results in contaminated ice.

The Ice Machine comes with a filter already – Ice Machine Filters generally run from 3 to .5 microns. They usually have carbon in them to remove other impurities (like disinfectants) but they are too large to control Legionella. A commonly mentioned standard is .20 micron filter to adequately control Legionella.

Legionella is transmitted via water vapor, how often do people get sick through ice? – Think of a pre-op patient sucking on ice. Though they’ve been thoroughly prepped, a simple cough can introduce Legionella into their lungs. Unfortunately, the old, the immunosuppressed patient, and certain classes of pre-Op patients are at risk from aspirating water from ice into their lungs.

We have a full range of filters large and small that are designed to work with the unique plumbing issues that Ice Machines can present. – An in-line .2 micron filter can easily be added after your existing filter, using standard couplings. AquaMedix provides a couple of different in-line filters that are appropriate for this use.

Conclusion: Ice Machines deserve some attention when it comes to Legionella prevention. Consider a secondary inline filter to control Legionella levels in your ice.


AquaMedix is focused on chemical free prevention of Legionella and other pathogens in hospitals, nursing home, and other institutions with vulnerable patient populations.


If you’d like to learn about how quickly and easily you can easily upgrade the filtration on your ice machines, or learn more about our other Point of Use and In-Line Filter options, please visit us at



Technical References:


EPA legionella_document_master_september_2016_final 09/documents/legionella_document_master_september_2016_final.pdf

Page: 38, section

Page 52 mentions .20 Micron size for bacterial control

VA Legionella Directive 1061 August 13, 2014
VA 1061
Page 15 – Item ee. Point-of-use filter.

One great reference for you and your customers is an article in the July 2017 Patient Safety Monitor Journal, “CDC Town Hall Q&A”. It features Q&As about how to deal with Ice Machines in a Health care setting. In-Line Filters are mentioned as a quick way to deal with Ice Machines in the event of suspected outbreak. You can read the whole interchange here at:





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