SDWA regulations, drinking water utilities continue to be challenged by their presence.
In contrast to traditionally regulated pathogens in the SDWA,
these emerging pathogens can be found in a wide range of natu-
ral and artificial environments (e.g., water, soil, building/home
water systems). Also, the primary modes of exposure (e.g., inhala-
tion, aspiration) for these pathogens differ from other drinking
In 1996, the U.S. Environmental Protection Agency (EPA)
amended the Safe Drinking Water Act (SDWA) to consider emerg-
ing waterborne contaminants for potential regulation in drinking
water. The SD WA has included Mycobacterium avium in the Third
Contaminant Candidate List (CCL3) for regulatory consideration.
Legionella pneumophila and Naegleria fowleri were also included
on the CCL3 in 2009. While these organisms have not resulted in
Grace Jang, Mary Smith, Kim Linton, and Frank Blaha, Water Research
Foundation; Edited by Jen Clancy, Corona Environmental
In the 1980s, water utilities were focused on water quality issues regarding coliform bacteria and the potential presence of Giardia cysts. In the 1990s, the list of water- borne pathogens grew exponentially, and the discovery of previously unknown microorganisms, which were responsible for waterborne outbreaks, raised concerns.