“The distribution system is the remaining component of public water supplies yet to be adequately addressed in national efforts to eradicate waterborne disease” (NRC, 2012). There is ongoing debate regarding whether water distribution networks contribute a measureable health risk derived from pathogens which can colonize these systems, and what significance a disinfectant residual plays in minimizing that risk. Current minimum disinfectant residual guideline values at the federal and state level in the United States have not been established using scientific evidence for the protection of the public from specific pathogens or health outcomes such as acute gastrointestinal or respiratory illnesses. Following the release of data from the Center from Disease control that suggested that 66% of all drinking water related outbreaks in the US were attributed to Legionella pneumophilia between 2011 and 2012, there has been increased discussion at the federal and state levels regarding increasing disinfectant residuals to combat these and other pathogens within the distribution system.