Winnipeg's boil-water advisory has been lifted.

“Our city's drinking water remains safe to drink," Mayor Brian Bowman said.

Bowman told a press conference at 3:30 p.m. CT, “The province’s medical officer of health has notified us that they have lifted the precautionary boil-water advisory for the city of Winnipeg."

Winnipeg had been under the advisory since Tuesday evening, when the city revealed six of 39 routine samples taken Monday showed signs of bacteria and E. coli​.

Bowman and Geoff Patton, the city's acting director of water and waste, said Wednesday that resampling efforts indicated the initial concerning results were false positives.

Mayor Brian Bowman drinks water

Winnipeg Mayor Brian Bowman chugged a glass of tap water Thursday afternoon. (CBC)

But because Health Canada requires two sets of negative samples 24 hours apart before it will lift a boil-water-advisory, the city decided to wait until more results were in Thursday.

"I'd like to thank all Winnipeggers for being patient in the last two days," said Bowman, holding up a glass of water at the press conference. "This is tap water, by the way, and we're good to drink it." Then he drank from the glass.

Bowman and the city have used social media to provide updates.

Officials said additional results came back negative for bacteria, but many questions remain about how the original samples resulted in false positives.

Patton repeated that the false positives may have been a product of sampling or testing error, but that it is too soon to be sure.

Diane Sacher, Winnipeg's director of water and waste management, said officials are taking a close look at the city's approach to sampling. "We did a review of our sampling and testing protocols and did make some changes, and so obviously we need to do something different this time."

Sacher said the city's primary concern now is to investigate the circumstances that led to the false results.

"That's obviously going to be a high priority for us now, to determine why that happened and find out what we can do to prevent that from happening again."