The expression “perfect storm” precisely describes Oahu’s current water-supply crisis.

Summer is almost here, bringing the annual prospect of reduced rainfall and heat, which usually means a draw on the islands’ underground aquifers. This year another worry looms: Contamination from military jet-fuel leaks continues to pose a danger, meaning water use almost certainly will be curtailed even more than usual.

And there’s been a serious breach in trust among residents who count on leadership to maintain their safety. This makes the imperative to conserve safe drinking water even stronger — and underscores the realization that the extent of the damage is still unknown to the community at large, and that the danger hasn’t passed.

Most concerning from the state Department of Health (DOH) is the finding that the plume of contaminants in the aquifer has drifted from the Navy’s Aiea Halawa Shaft that the Navy ceased using, and is moving toward the Honolulu Board of Water Supply’s Halawa shaft. This source had been providing 20% of the water for urban Honolulu until it was shut down to help stem any migration of the spill, along with two more sites, the Halawa and Aiea wells.

The Navy’s failures since the most recent crisis last year at the Red Hill Underground Fuel Storage Facility, the root cause of the contamination, have become even more distressing in recent weeks. To begin with, there have been anecdotal reports from military families who still believe contamination is persisting.

Then the state DOH on May 13 released well data showing increasing levels of contamination in the months following the May 6, 2021, fuel spill in the facility system, indicating that spill hadn’t been contained as Navy officials had said. Then in November, analysis showed the levels spiking higher after fuel was detected in a well serving primarily military families.

Precisely just what happened through that period is not yet publicly known. On that same date, the Health Department received a long-awaited copy of an assessment report prepared for the Navy by its contractor, Simpson Gumpertz & Heger Inc. But the Navy has designated this document as “critical infrastructure security information,” precluding its release to the public by the DOH.

Fortunately, the state agency’s current emergency order governing the planned closure of the storage facility requires the Navy to issue a copy for public release by Friday. That deadline must be met: Residents need the facts of the health hazard beneath their feet.

That hazard became visible in the form of DOH heat maps that show graphically where levels of total petroleum hydrocarbons (TPH) from the diesel fuel have increased. In the year before the May 2021 fuel release, diesel levels were as high as 2,000 parts per billion (ppb).

In the months thereafter, the detections peaked at 4,100 ppb in February and March before dropping. That’s stunning. The federal environmental action level that could trigger an intervention is 400 ppb.

The better news, according to the department’s sampling results, is a general decline in TPH levels in mid-January through April this year, its most recent data.

But it’s producing enough worry that the Honolulu Board of Water Supply is contemplating a search for alternative water sources to replace the Halawa shaft in case it can’t be restarted. Ernie Lau, BWS chief engineer, is asking U.S. Sen. Brian Schatz for a $195 million earmark in federal funds to cover the costs.

In any case, Lau makes a persuasive argument that the Navy should be the agency responsible to pay the bill for well exploration. Solutions to Oahu’s water crisis will be expensive, and the bill should not fall on the ratepayer.

In a Honolulu Star-Advertiser “Spotlight Hawaii” webcast on Friday, Lau said the BWS is looking for further development, proceeding with a desalination project procurement.

More immediately, he currently believes the voluntary conservation efforts will see Oahu through the summer; an “alert water shortage” status would mean that wells still could operate 20 hours a day. But mandatory restrictions with more operational constraints could be implemented by the board if water levels continue to drop, he said.

That means residents must do everything they can now to keep demand within supply limitations. Some government agencies are modeling some good water protocols that residents could apply to their own home routines. The city Department of Parks and Recreation, for example, is reducing field irrigation, scheduling watering during twilight hours and taking myriad other steps.

The overarching concern now is that the Navy meet its commitments to remove the environmental threat altogether. Lau acknowledged the timeline the state has laid out for the Navy to begin the process of defueling the Red Hill tanks — a defueling plan by June 30, for instance — but he urged the public to “stay on them.

“If we go silent,” he added, “the timelines might stretch out.”

Absolutely right. This is no time for the public to be quiet.