NORS was launched by the CDC in 2009 as a web-based platform, where public health departments from the United States can voluntarily enter information regarding the outbreak.

Through NORS, enteric as well as non-enteric disease outbreak data are reported.

During 2015-2020, 214 outbreaks were associated with drinking water, and health officials reported 454 contributing factors from 28 states.

Public water was the most common source of these outbreaks, leading to 172 outbreaks.

Among enteric illnesses, Norovirus, Shigella, and Campylobacter, or multiple etiologies including these pathogens, resulted in 94% of cases, and often the cause was the source of drinking water.

In biofilm-related outbreaks, 98% were Legionella, and the rest were non-tuberculous bacteria and pseudomonas.

NORS enhances the efforts of the CDC to estimate the healthcare cost impacts of waterborne and drinking water-associated diseases.