LONG BEACH, N.Y. (CBSNewYork) — The boil water advisory that was put in place in Long Beach after a water sample tested positive for E. coli has been lifted.

Health officials conducted dozens of tests for two consecutive days, and they say they were all negative for E. coli.

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“I’m pleased to report this morning that the test results we just received are negative for E. coli. This follows results which showed no detections that we received yesterday,” Dr. Howard Zucker, the NYS health commissioner, said Monday morning.

Officials made the announcement after Long Beach administrators sent a letter to parents saying East, West and Lindell elementary schools would be closed Monday. Administrators said a student was diagnosed with a possible E. coli infection.

“Although we can provide adequate bottled water for students and staff to drink, we cannot guarantee proper handwashing among students,” the letter continued. “Even though this is really precautionary, and we have been assured by the city that they hope that the alert will be lifted soon, we do not want to take any chances with the health and safety of our students and staff.”

The school year is still expected to wrap up Wednesday.

Web Extra: Long Beach Ends Boil Order Over E. Coli In Drinking Water:

The boil advisory had been in place in the city of 35,000 since Friday afternoon. The state’s Office of Emergency Management stepped in to provide more than 100,000 bottles of water.

It was a cause of frustration for residents and business owners.

“It’s been hard. We have no coffee. Since the weekend, no ice coffee. Our customers left because of it, you know, so we lost a lot of business, unfortunately,” Christine O’Connor, manager of Beach Bagel and Deli, told CBS2’s Carolyn Gusoff.

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“We have a 1 1/2-year-old son, Lucas, as you can see here. He has been bathing in boiled water for the past three days, which is either too cold or too hot and uncomfortable,” Lauren Doddato-Goldman said.

Alexis Pace said her daughter was diagnosed with an E. coli infection.

“Extremely ill. She was in the hospital treated for dehydration. She is home, but she cannot get off of the toilet,” Pace said.

Health officials say efforts to pinpoint the source of the E. coli in the water are still underway, but they may never know.

“When we get these cases, which is rare and sporadic, very often we don’t find the source, but the chlorine that’s put in the water eradicates it,” Dr. Lawrence Eisenstein, Nassau health commissioner, said.

That has residents concerned it could happen again, and some are now calling for an upgrade to the city’s aging water infrastructure.

“We know we need a new system. We need it upgraded. We need it done now,” Nassau County legislator Denise Ford said.

It is still possible that someone will get sick fro drinking water last week before the advisory, but the health commissioner says that is unlikely. The positive sample was collected last week and the illness would have likely presented by now.

It usually takes about three days to show signs of E. coli exposure. Symptoms can include diarrhea, abdominal cramps, nausea, vomiting and fever.

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For more information, contact the City of Long Beach at (516) 431-1000.