An outbreak of gastrointestinal illness associated with contamination of the mains supply by river water.

In June 1992 a department of public health was informed of an outbreak of illness that was thought to be associated with contamination of the mains water supply to a farm. A field investigation identified 42 cases of acute gastrointestinal illness among 117 people potentially at risk, and found that the mains water supply to the farm was connected to an irrigation system that used water from a river. This outbreak illustrates the danger of connections between potable and non-potable water systems, and emphasises the importance of complying with existing water byelaws.