The New Hampshire Department of Environmental Services has issued a warning to Lebanon residents to boil their water for two minutes before use following the detection of bacteria in the city's water distribution system.
City officials say monthly test results returned Thursday confirmed the presence of coliform and E. coli bacteria in the water.
The boil water order affects nearly 15,000 residents and also includes the Alice Peck Memorial Hospital and Dartmouth-Hitchcock Medical Center, which have plans to use safe water.
Health officials say the bacteria might have come from contamination by human or animal waste. The source hasn't been identified.
City officials say they are evaluating the water system and will take new samples for testing.
The order remains in effect until tests show the bacteria are gone.