TAMPA, Fla. (WFLA) – Officials from the Tampa Water Department have spent days testing the city’s water supply after that major water main break Monday.

“The first round of water quality testing after issuing a precautionary boil water notice late Monday afternoon has shown satisfactory results with no evidence of contamination,” a statement from the department says. “The results of the second round of water quality testing will become available [Thursday] morning. Twenty-four samples were collected from locations throughout our service area. These locations included nursing homes, hospitals and highly populated areas.”

The city was forced to issue a precautionary boil water notice for all city residents and businesses as well as about 20 percent of those who live in Hillsborough County.

On Tuesday night, the city posted on social media a photograph that shows the 36-inch main with a huge gash in its side. Officials say the water main was hit by a piling operated by a contractor working in the area, causing pressure to drop rapidly.

8 On Your Side turned to Jeff Cunningham, an associate professor at the University of South Florida.

“The water mains that carry the water from the treatment facility to your house, they stay under pressure, so that if there’s any sort of crack or leak in the pipe water will only flow out of the pipe, you won’t have any dirty water flowing in,” he explained.

City officials urge people to boil their water for 60 seconds or add a tiny amount of bleach to it. Those procedures can rid the water of any contaminants or bacteria.

“The risk is if the pressure in the pipe gets low, it might give an opportunity for dirty water outside the pipe to infiltrate inside the pipe and end up in your kitchen sink,” Cunningham said.

The Tampa Water Department is in the process of testing the city’s water. The department turns over its results to the Florida Department of Health-Hillsborough County.

“Our role from DOH is to ensure that samples are taken throughout the water system, that it’s comprehensive enough to cover the entire impacted area,” said Kevin Watler, a spokesman for the department.

The notice is expected to be lifted Thursday or Friday after the second set of test samples come in, officials said.

“As a precaution we advise that all water used for drinking, cooking, making ice, brushing teeth, or washing dishes be boiled. A rolling boil of one minute is sufficient. As an alternative bottled water may be used. This precautionary boil water notice will remain in effect until the problem has been corrected and a bacteriological survey shows that the water is safe to drink,” a statement from the water department says.

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