This study examined 184 legionellosis outbreaks in the United States reported to the Centers for Disease Control and Prevention's Waterborne Disease and Outbreak Surveillance System, from 2001 to 2017. Drinking water characteristics examined include source water type, disinfectant type, exposure setting, geographical distribution by U.S. Census Divisions, and the public water system size (population served). This study found that most of the reported drinking water-associated legionellosis outbreaks occurred in eastern United States, including 35% in the South Atlantic, 32% in the Middle Atlantic, and 16% in the East North Central Census Divisions were linked with building water systems in healthcare and hotel settings; and were associated with buildings receiving drinking water from public water systems serving >10,000 people. Targeted evaluations and interventions may be useful to further determine the combination of factors, such as disinfectant residual type and drinking water system size that may lead to legionellosis outbreaks.

Hepatitis A virus (HAV) is an RNA virus primarily transmitted via the fecal-oral route and, in rare cases, causes liver failure and death in infected persons. Although drinking waterassociated hepatitis A outbreaks in the United States are rarely reported (1), HAV was the most commonly reported etiology for outbreaks associated with untreated ground water during 1971-2008 (2), and HAV can remain infectious in water for months (3). This report analyzes drinking water-associated hepatitis A outbreaks reported to the Waterborne Disease and Outbreak Surveillance System (WBDOSS) during 1971-2017. During that period, 32 outbreaks resulting in 857 cases were reported, all before 2010. Untreated ground water was associated with 23 (72%) outbreaks, resulting in 585 (68.3%) reported cases. Reported outbreaks significantly decreased after introduction of Advisory Committee on Immunization Practices (ACIP) hepatitis A vaccination recommendations* and U.S. Environmental Protection Agency's (USEPA) public ground water system regulations. † Individual water systems, which are not required to meet national drinking water standards, § were the only contaminated drinking water systems

Drinking water distribution system deterioration can affect the water supply and reliability as well as water quality and public health.

Distribution system infrastructure issues can affect water reliability and quality and could contribute to waterborne disease outbreaks. It's important to know potential contamination mechanisms and consider rehab and replacement options.

There has been an increasing focus in the past few decades on public health risk associated with distribution systems and, as a result, an increasing focus on possible expanded regulatory requirements for them. However, despite significant advances in understanding and managing distribution system water quality in recent years, there are still critical areas of uncertainty and knowledge gaps that must be filled in order to better understand public health risks and to cost‐effectively minimize them. The research and information collection activities identified through the Research and Information Collection Partnership (RICP) will result in more effective and pragmatic regulation, underpinning rulemaking decisions with sound, credible science. The RICP represents collaboration between the water utility community and regulators toward a common goal of public health protection. RICP activities are expected to support future risk management decisions by the drinking water community, such as development of guidance, best management practices, policy, and regulation for improved distribution system management. Guiding these efforts is the RICP priorities document, which is a roadmap of research and information collection activities that should be undertaken by water suppliers, federal and state agencies, and other stakeholders over the coming four to five years. Water utility support of and participation in these activities is vital to their success, and water suppliers may also use this information for education and training purposes.