Plumbing and Legionella: Setting the Record Straight

  August 19, 2013

It might seem that technology puts more information in the hands of maintenance and engineering managers than ever before. While that might be true, the information might not be accurate. Consider the example of Legionella, the bacteria that causes Legionnaire's Disease.

Since it was identified in 1976, much progress has been made in understanding the disease, its causes, where the bacteria is found, its health risks, and how to protect against it. It has also sparked many myths, from outright falsehoods to unsubstantiated claims that have no evidence to back them up.

Separating fact from fiction can be a challenge. Plumbing Manufacturers International (PMI) has taken on this challenge as part of an ongoing effort to address the myths surrounding the industry and to promote safe and healthy installation and maintenance practices.

One of the most widespread myths is that Legionella can be seen with the naked eye, and such discussions often include a photo of a calcified showerhead as an example. This is false. The presence of mineral deposits on plumbing fixtures does not mean Legionella is present.

But Legionella can grow in certain types of mold. Slime molds, also known as biofilm, can provide ideal breeding grounds for Legionella. As with any mold growing in buildings, biofilm should be taken seriously and be properly tested, analyzed and removed. Testing for biofilms and Legionella should be done routinely and should span the entire plumbing system, as they can spring up at any place along the network of pipes and fixtures. Maintenance supervisors, facility managers, and health and safety engineers should set up routine checks and tests and send samples to be professionally tested in proper labs for Legionella. This testing will assist in understanding the levels of the bacteria present and can help determine the proper way to remove it from the building.

Removing Legionella can be done in a multitude of ways, from flushes of hot water strong enough to kill the bacteria to chemical baths and hyperchlorination to copper-silver ionization and ultraviolet light purification. Each style features certain benefits and drawbacks, and each requires a working knowledge of the building's system.


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