A treatment plant at the center of water woes in Mississippi’s capital city made “significant” gains overnight and into Saturday, Jackson officials said.

According to a news release, the O.B. Curtis Water Plant’s total plant output increased to 86 pounds per square inch, approaching the city’s goal of 87 PSI or better.

“The outlook is very stable,” the city said in the statement. “However, additional challenges as repairs and adjustments are made do leave the potential for fluctuations in progress.”

The city said most customers should have water pressure, and only a few remaining pockets in south Jackson may still be experiencing low or no pressure.

“Work continues in the plant today on both the membrane and conventional systems. This work is initially focused on increasing the production ability of the O.B. Curtis facility,” according to the release. “Increasing the production ability will create more stability in water supply.”

Teams from Georgia and Florida rural water associations are also on-site, assisting with repairing and restoring many of the automated systems that will support better management of the production of water and water quality, the city said.

Mayor Chokwe Antar Lumumba said at one news conference that, once pressure is restored, there are worries about the strain on aging, brittle pipes.

And even when water is running again, it’s unclear when it will be drinkable.

Last week’s rains, followed by flooding of the Pearl River, exacerbated long-standing problems at the O.B. Curtis treatment plant, leading to a drop in pressure throughout Jackson, where residents were already under a month-old boil-water order due to poor water quality.

The problems led to a Monday emergency declaration by the Republican governor and a disaster declaration from President Joe Biden.

Meanwhile, the Mississippi State Department of Health said residents may see flares at the plant as crews work to transfer ammonia from a leaking tank for repair.

“There may be a controlled burn-off of the gas that may cause a visible flare into the sky,” said Jim Craig, a state health official, in a news release. “There is no need for concern and there is no threat to the public.”

Anhydrous ammonia is a colorless nonflammable liquefied gas. Its vapor is lighter than air and has the same pungent odor as household ammonia. A propane flare is established at the site to burn-off any gas that may escape the transfer of product and repair of the leaking ammonia tank.

The National Guard has been called to help with water distribution. The state emergency agency said close to 2.8 million bottles of water were handed out from midday Thursday to Friday afternoon. Nonpotable water, for toilet flushing and other uses, was also being offered to people who brought their own containers to some sites.

The entire city had been without water or with low pressure at one point. Figures on how many homes and businesses had service restored were not available.