Two confirmed cases of Legionnaires’ disease in Pennsylvania- one in a hospital and another in a nursing and rehabilitation center- have once again brought waterborne risk into sharp focus.

A recent update from the Ector County Health Department has brought renewed attention to the risks associated with waterborne pathogens. Since mid-November, 12 cases of Legionnaires’ disease, including two fatalities, have been confirmed, with case numbers rising through late December and early January.

When evaluating point-of-use water filters for a healthcare facility, two numbers appear more often than any others: the pore size in microns and the log reduction value. Both describe how thoroughly a filter removes bacteria from water. Both are independently certified under recognized US and international standards. And both differ significantly between filters that carry the same general description, "anti-Legionella", but perform quite differently in practice.