The Alliance to Prevent Legionnaires’ Disease, a non-profit public health organization advocating a comprehensive approach to disease prevention, welcomes the recent decision by the Pennsylvania Department of Environmental Protection and the state’s water utilities to take steps to advance the safety of the water supply and distribution system. Requiring water systems to maintain a 0.2 mg/L chlorine residual throughout the distribution system should reduce the risk of human infection, including from legionella bacteria, caused by ingestion or other means such as inhalation and blood contact. In general the Alliance believes water distribution endpoints (prior to water entering our homes and building) are a critical area in waterborne disease prevention.
The Alliance concurs with the rationale provided by the state in the Pennsylvania Bulletin Proposed Rule from February 20, 2016 which states, “The distribution system is the remaining component of the public water supplies yet to be adequately addressed in National efforts to eradicate waterborne disease.” We encourage other states who do not have similar minimal chlorine residual requirement throughout the system to consider the steps taken in Pennsylvania. Adopting similar rules and guidelines will better protect their residents, particularly those with compromised immune systems, from the risks associated with a wide variety of waterborne pathogens in water distribution systems.