Officials in Corpus Christi, Texas, announced that a city water ban had been fully lifted on Sunday, following fears of potential contamination from an industrial chemical leak at an asphalt plant.

The entire water system for the Gulf Coast city of 320,000 was back "in full use" as of Sunday morning, Mayor Dan McQueen said at a press conference.

Officials said they would continue to monitor the situation going forward, he said, admitting that there was still a possibility of "a plume of contamination in the water system."

All 30 samples that were tested Saturday by the Environmental Protection Agency and the Texas Commission on Environmental Quality were currently at non-detect levels for contaminants, the mayor said.

Related: Corpus Christi Water Ban: Here's What to Know About the Possible Contamination

The EPA confirmed in a statement Sunday that none of the 28 drinking water samples collected from across the city water system from Dec. 15-16 tested positive for the presence of the chemical officials feared had leaked into the water supply, Indulin AA-86, at their method detection levels.

"As we look at this, we’re going to continue the sampling process and the city is still in a partnership with TCEQ and the EPA on evaluating our entire water system," the mayor said.

Both agencies were currently evaluating "every health concern that's out there right now" and working to see if there was any contamination they might have missed, he added. Officials had finished flushing Zone 3 of the city, which had been banned from using the water completely as a precaution.

The ordeal was unnerving for Corpus Christi residents, especially those who live near the asphalt plant.

"Have we been exposed?" Carol Gonzalez asked. "We just don't know."

Her family lives less than a mile away and her husband, Anthony Gonzalez, had made spaghetti for their 9- and 10-year-old daughters the night the water use ban was announced.

The couple, interviewed while picking up a free case of bottled water at a city-run senior center, had already spent $150 on water, not to mention eating out. And they've been driving out of the city to fill buckets of water they use to bathe their children, who include a 6-month-old girl.

"It's gotten very expensive, and there's not going to be any reimbursement," Carol Gonzalez said.

McQueen urged city residents to be conservative in their water use on Sunday, saying he did not want to risk too much burden on the water system.