Water samples tested in the last 24 hours in Winnipeg have come back clean, but a boil water advisory remains in effect as city officials await the all-clear from the province.

The Winnipeg Regional Health Authority initially issued a boil water advisory for the entire city on Tuesday, after low levels of bacteria, including E.coli, were detected in water samples.

At a news conference Wednesday, Mayor Brian Bowman said the original samples may have indicated false positives.

The advisory remains in effect as the province conducts further testing.

“The province has the authority to lift the precautionary boil-water advisory,” Bowman said. “Once we receive that indication, we'll obviously notify Winnipeggers as quickly as possible.”

Winnipeg's Water and Waste Department manager of engineering services Geoffrey Patton said they re-tested water samples from six locations and all came back clean.

“We also re-sampled upstream and downstream of those locations at all six sites, and all of those samples came back negative,” Patton told reporters.

Patton said results from the provincial re-sampling are expected to come back Thursday afternoon.

While the advisory continues, Winnipeg residents must bring their water to a rolling boil for at least one minute before it is used for drinking, cooking, brushing teeth, making ice and preparing infant formula.

If boiling water is not feasible, residents are urged to use bottled water.

The health authority says it is not necessary to boil water for other household purposes, such as washing dishes and doing laundry.

Many citizens have snapped up cases of bottled water from area grocery stores.

Extremely low levels of E.coli were detected in six of 39 samples tested on Tuesday, but experts questioned whether the tests were correct. The positive results found odd chemical and bacterial pairings that would not normally appear together in a proper sample.

Patton said Wednesday afternoon they don’t know what caused the original samples to indicate harmful bacteria, but they will be investigating. Bowman promised to make the findings public.

“There were no issues with the distribution system or our operations,” Patton said. “All indications is that there was some sort of error, either in the sampling methodology or in the testing.”

As the advisory remains in effect, the public health scare is having a big impact in the city.

A power outage made matters worse for approximately 9,000 customers who lost power in the city’s north end Wednesday afternoon, after a fire affected a power line.

Hydro crews were working to restore power, but without electricity, affected residents couldn’t boil water.

In other parts of the city, restaurants were forced to boil water, and schools shut down the use of drinking fountains. Hospital were bringing in bottled water for patients.

Grocery and drug stores were overwhelmed by the demand, and some sold out of bottled water.

The shortage created online opportunists: An ad on Kijiji offered four gallons of water for $100.

This is not the first time the city of 700,000 has dealt with water supply issues.

In 2013, the city issued a localized boil-water advisory for one neighbourhood, only to lift it when no E. coli contamination was detected.

Then, last winter, frozen pipes left thousands of residents without running water for weeks.

With the latest scare, some residents say they will continue to buy water for drinking.

“It’s bottled water for me,” said one man purchasing eight jugs of water. “Or Coke, or anything else that comes in a can or bottle.”

With a report by CTV’s Manitoba Bureau Chief Jill Macyshon