Water company officials say customers of five public water systems serving parts of Narragansett and South Kingstown may need to boil their water for several more days.
The state health department issued the boil water notice on Friday after e-coli bacteria was found during routine sampling by Suez Water, which sells water to the other local systems.
About 38,000 residents are impacted.
An online map shows the affected areas. There's also a list of the streets.
Water used for drinking, cooking, making ice, brushing teeth and washing dishes should be boiled for at least one minute, or use bottled water. The department says young children shouldn't be bathed in this water because they may swallow it.
E. coli can signal the presence of fecal matter.