Officials "are optimistic that we can see water restored to our residents within this week" in the city of roughly 150,000 residents, Mayor Chokwe Antar Lumumba told CNN Wednesday.
"There is a huge mountain to climb in order to achieve that," he said. Crews "are working persistently to restore the pressure, to refill the tanks across the city," Lumumba said.
But the water crisis still is upending nearly all aspects of life in the city, where public schools shifted to virtual learning Tuesday.
Cassandra Welchlin, a mother of three, told CNN her kids are out of school and they've had to buy water to cook, brush their teeth and for other basic necessities.
Brown water has been running from her taps, said Welchlin, executive director of the Mississippi Black Women's Roundtable.
"We still would not use that water. We don't boil it to do anything with it because grit is in the water," she said. "It's a really bad public safety issue."
President Joe Biden, who signed a major disaster declaration Tuesday triggering assistance from the Federal Emergency Management Agency, spoke to Lumumba on Wednesday to discuss emergency efforts, the White House said.
Residents and businesses still face numerous challenges.
At a water distribution event Tuesday at Hawkins Field Airport, residents waited in a line more than a mile long -- and some were turned away when the site ran out of its 700 cases of water in just two hours.
Some stores ran thin of supplies. Jackson resident Jeraldine Watts was able to snag some of the last water bottle cases at a grocery store Monday, she told CNN. She and her family have been using bottled or boiled tap water for everything, including cooking and washing dishes.
"I keep saying we're going to be the next Michigan," Watts said, "and it looks like that's exactly what we're headed for."
At Jackson State University, there is "low to no water pressure at all campus locations," and water is being delivered to students, officials said. The university's head football coach, Deion Sanders, said its football program is in "crisis mode."
The water system has suffered from "deferred maintenance over three decades or more," and the city will need funding help to catch up, Lumumba said earlier this week.
What happened, and what officials say is being done
The governor said he was told Friday that "it was a near-certainty that Jackson would fail to produce running water sometime in the next several weeks or months if something did not materially improve."
O.B. Curtis received additional water from a reservoir because of the flooding, and that changed the way the plant treated the water, causing the plant to produce even less than it was, and that severely lowered the water pressure across the city, Lumumba said Monday.
Some improvements have been made at the plant, but more is needed, state officials have said.
On Tuesday, the plant was pumping about 30 million gallons of a day; it is rated to pump about 50 million gallons a day, Jim Craig, director of health protection at the state health department, told reporters Tuesday.
On Wednesday, an additional pump was being installed at the plant, city spokesperson Melissa Payne said.
Reeves previewed the installation Tuesday night, saying a rented pump "will allow us to put at least 4 million gallons" more into the system.
"That is progress and will help," Reeves said Tuesday. It wasn't immediately clear how long the installation would take or how soon it could impact the city's water flow.
"I have said on multiple occasions that it's not a matter of 'if' our system would fail, but a matter of 'when' our system would fail," the mayor said Tuesday, adding that the city has been "going at it alone for the better part of two years" when it comes to the water crisis.
Lumumba told CNN the city is working on more water distribution events.
Beginning Thursday, seven mega distribution sites with 36 truckloads of water will be available each a day for the public, Lt. Col. Stephen McCraney, director of the Mississippi Emergency Management Agency, said Tuesday.
Corporations like Anheuser-Busch, Walmart and Save A Lot, as well as volunteer organizations are also donating water to the city, McCraney added.
The city is also providing flushing water, Jackson City Councilman Aaron Banks told CNN.
"One of the first things that we realized is that people need to be able to flush, because that becomes a problem as far as making sure that people have that quality of life that they need," he said.
"At the end of the day, we need a fix and the same attention that was given to Flint, Michigan, we need that same attention given to Jackson," Banks said.
Maise Brown, 20, a junior at Jackson State, organized the group of about 20 students, called Mississippi Student Water Crisis Advocacy Team. The group launched a social media campaign Tuesday to raise money and to publicize the hotline.
As of Wednesday morning, the group raised about $2,000 and received about 10 calls asking for help.
"We had disabled residents calling us ... for help," Brown said. "We also had people who live outside the city call us and ask us to help their elderly parents."
The group plans to knock on the doors of homes, hoping to reach people who might not see its social media campaign, Brown said.
Long-standing issues at troubled water system
"Since that time, there has not been a month where we have not experienced no-flow to low-flow in certain areas in south Jackson, and so it's very frustrating," Banks, the city councilman, told CNN.
CNN's Amir Vera, Melissa Alonso, Amanda Musa, Pamela Brown, Caroll Alvarado, Amy Simonson and Betsy Klein contributed to this report.