AUSTIN, Texas >> Roughly 1 million people in Austin have had to boil their water since Saturday after officials said “errors” at a treatment plant resulted in potentially unsafe water flowing into homes and businesses in one of the largest and fastest-growing U.S. cities.

It was the second time in a year that residents of the Texas capital have been told to boil water before drinking. Last February, the problems were caused by the collapse of the state’s electricity grid, which resulted in power failures at Austin’s largest water treatment plant.

But city officials said the issues at the Ullrich Water Treatment Plant over the weekend were unrelated to a winter storm that caused temperatures to plunge across the state late last week.

“This is a very different event than what happened last year,” City Manager Spencer Cronk said during a news conference Sunday.

In a state still traumatized by the failure of its electrical systems during a bitter cold last year, the directive over the weekend to boil water caused frustration and anger across Austin. The notice is likely to remain in effect for the entire city until at least Tuesday afternoon.

“We have to do a better job,” said Mayor Steve Adler during a television interview Monday. “In our city, we can’t have our water system going down like this.”

Adler said 7,000 cases of bottled water had been distributed by the city, along with 6,000 gallons of water from delivery tankers. Still, he said, the situation was “incredibly frustrating for everybody in this city.”

Water officials said that by Friday, they had weathered last week’s storm without incident. But about 8 a.m. Saturday, the head of Austin Water, Greg Meszaros, was alerted to a spike in “turbidity” — the cloudiness of the water going out to consumers — at the Ullrich plant. The plant was immediately shut down.

“They’re essentially water factories,” Meszaros said at the Sunday news conference. “And sometimes in factories, you’ve got to stop the assembly line. And that’s where it was not properly stopped and corrected, and it was allowed to carry through to the finished water, and that’s just not appropriate.”

Meszaros said the failure had been caused by “errors from our operating staff at our Ullrich plant” and said an investigation was continuing. It was not immediately clear at what point the errors occurred or how many people were responsible.

Austinites have become reluctantly familiar with boil-water notices. In addition to the winter storm last year — which left nearly 7 million Texans under a boil-water advisory — flooding created problems to Austin’s water supply in 2018, resulting in a boil-water notice.

“Austin is the tops, but being able to provide safe drinking water, that should not be one of the challenges we have to solve,” said Natasha Harper-Madison, a City Council member. “It’s beyond frustrating to have to go through this kind of incident with this frequency.”

Hilda Salinas, 60, was cooking sopa de fideo for her 1-year-old grandson Saturday afternoon when she heard about the boil-water notice. Salinas recalled shaking her head in defeat and throwing the soup away.

“I didn’t trust it to be safe for my grandson to eat,” she said.

Salinas, a retired U.S. Postal Service worker who was at a city-run distribution site Monday to pick up a case of bottled water, expressed a common frustration among residents of Austin, where real estate values are skyrocketing as new arrivals pour in.

“I mean taxes are high, getting higher, and they can’t get the water straight,” Salinas said. “I don’t know what else to say.”

Paula Mendoza was also among those picking up bottled water at a water facility Monday — her 61st birthday. Mendoza said she had been laid off from her job at a nonprofit last month and could not afford to buy her own cases.

“Money is tight right now,” she said. She said she drank water from her faucet during part of Sunday until a friend called her to let her know about the water notice. “Today is my birthday,” she said. “I can’t get sick.”

Many residents who could afford to do so had prepared for a possible water outage because of the winter weather passing through last week, stockpiling water and filling bathtubs.

“Unfortunately, we’re getting pretty well versed in how to protect our families,” said Paige Ellis, a City Council member who has called for a special meeting of the council to look into circumstances at the Ullrich plant. Two other treatment plants in the city had been operating normally.

Officials said the kind of human error that appeared to be behind the current need for residents to boil their water — for two minutes, at a rolling boil — was unusual if not unprecedented.

“It’s never happened before,” Meszaros said. “It’s not easy. We have many controls in place.”

This article originally appeared in The New York Times.