EPHRATA — Ephrata and the state Department of Health are advising residents to boil their tap water or buy bottled water until further notice.

The state Department of Health and the city issued the order Friday after discovering potentially harmful bacteria during routine testing.

The order affects 7,100 people, including 3,200 homes and businesses in the city.

The health advisory includes several precautionary steps customers should take: Use boiled water or bottled water for drinking, brushing teeth, preparing food, dishwashing, and making ice.

Tap water should be boiled for one minute and allowed to cool before use.

Routine tests on Wednesday afternoon showed a single occurrence of Escherichia coli bacteria, commonly known as E. coli. A second test of the same water came back negative on Friday morning, City Administrator Wes Crago said. After receiving the positive result, the city tested the water at two wells.

“The sample from one of the wells showed a preliminary indication of contamination,” he said. “The city and the Department of Health decided to act out of an abundance of caution and issue the health advisory.”

The contamination is non-acute coliform. The Department of Health Web site states the bacteria is not likely to cause illness.

“Their presence in drinking water indicates that disease-causing organisms (pathogens) could be in the water system. Most pathogens that can contaminate water supplies come from the feces of humans or animals,” according to the department.

The samples showing the non-acute coliform tested negative for E. Coli, Crago said.

The wells were taken out of service once they were tested, Crago said, adding the city can go several days during this time of year on stored water.

The city’s first priority was to notify the residents and businesses, he said, adding it was finished today.

“Our second priority is disinfecting our water system and the third priority is the safe restoration of our drinking water,” he said.

Crews started disinfecting the system Friday morning, adding chlorine until the bacteria is removed from the system. The chemical is removed and the water will be tested again, Crago said.

“Then we have to have all the chlorine out of the system before we can lift the boil order,” he said, adding the order will be lifted,

“When the system has been insured to be safe … we’ll issue a news release to let people know that they can go back to using the water.”

The Department of Health stated the advisory is likely to remain in effect for several days.

“No illnesses have been reported to the department in conjunction with this water contamination event and we’re pleased with how quickly the city has responded to this situation,” said Denise Clifford, director of the Office of Drinking Water. “We’ll continue to work with them and the other partners to ensure that Ephrata residents have safe and reliable drinking water.