Oahu residents are facing mandatory restrictions on their water use, and developers could have to grapple with a moratorium on new construction as the hot, dry summer months approach — consequences of a reduction in water capacity due to 2021’s Red Hill emergency.

But Gov. David Ige on Monday said that this lost capacity could be made up if the Honolulu Board of Water Supply fixed its wells that have been down for repairs, an assessment BWS Manager and Chief Engineer Ernie Lau said isn’t accurate.

“One of the things we have expressed to the Board of Water Supply, they have about 15% of the wells that are currently down because of repairs,” Ige told the Honolulu Star-Advertiser’s “Spotlight Hawaii” live^­stream program. “If they were to focus on repairing that 15% of the wells, it would restore more than the water that we’ve lost due to this Red Hill situation.”

Ige said fixing these wells “that are just down for equipment or maintenance malfunctions” would allow them to “get back into production right away.”

But Lau told the Star-­Advertiser that while that could help, it wouldn’t solve Oahu’s water problems.

“We don’t completely agree with his analysis, and we would like to see his numbers,” said Lau.

The governor’s office said Ige’s information came from the state Commission on Water Resource Management, an agency under the state Department of Land and Natural Resources.

“It is based on the commission’s dataset, though the commission says the information has not been verified by BWS,” said Jodi Leong, a spokesperson for the governor.

Lau said there are 90 well stations islandwide and that it’s normal for the pumps to periodically undergo maintenance or replacement. “We will always have pumps under repair,” said Lau.

To handle that contingency, he said, the BWS ensures there is enough backup supply.

But that backup supply was compromised in 2021 when jet fuel leaked from the Navy’s underground Red Hill fuel storage facility. In December the BWS shut down its Halawa shaft and two other wells to make sure the fuel didn’t migrate through the aquifer into its drinking water system, which supplies water to Oahu residents.

The biggest well was the Halawa shaft, which normally provides 20% of the water to more than 400,000 residents from Moanalua to Hawaii Kai. The two other wells that were taken offline provide 50% of the water to a smaller system that serves about 20,000 customers in the Aiea and Halawa region.

To make up for the lost supply, the BWS has been exploring the development of new water sources, which could take a number of years, and urging Oahu residents, government agencies and businesses to voluntarily reduce their water use by 10%.

Lau said the BWS also is expediting the repair of its offline wells and equipment, but this too takes time. The wells also need to be recertified by the state Department of Health, which can take several months.

One of its oldest stations in Kalihi has been undergoing repairs since 2017 and has eight artesian wells and five pumps out of service, according to the BWS. Additionally, three wells and three pumps are down at its Kalauao station, and two pumps and two wells are down at Punanani.

The BWS didn’t immediately provide a figure Monday as to how much capacity would be added when those are fixed, but said major repairs to the Kalihi station were able to proceed because, at the time, its Halawa shaft was online.

Ige also said Monday that he supports BWS efforts to develop more water sources and has instructed all state agencies to reduce water use by 10%.

“We want to lead by example,” said Ige.