Effect of a boil water notice on behaviour in the management of a water contamination incident.

In late 1998, the water supply of 878 households was affected by possible sewage contamination. A notice was issued to advise residents of the need to boil their water. This provided an opportunity to assess to what extent the boil water notice led people to avoid activities that might put them at risk of waterborne infection. A postal questionnaire sent to 350 randomly selected households in the affected area asked about timing and mode of receipt of the notice, risk behaviour (boiling water, brushing teeth, washing dishes, drinks for pets, preparation of food), and subsequent changes in drinking water consumption habits. Eighty-one per cent of the households surveyed engaged in behaviour likely to increase the risk of waterborne infection. Comments were collected from consumers on how to improve the management of future water contamination incidents.