A boil water order is in effect for Norwell.
Town officials say that on Wednesday they were notified that a sample collected on Tuesday was positive for E. coli bacteria.
Residents are being advised to use bottled water or bring all water to a rolling boil and let it boil for at least one minute and that until further notice boiled or bottled water should be used for drinking, making ice, food preparation, brushing teeth and washing dishes.
In addition it is advised to discard all ice, beverages, uncooked foods, and formula made with tap water collected on or after Tuesday.
Officials say they are flushing water mains and increasing chlorination and will inform residents when tests show no bacteria and the boil water order is no longer needed.