This was not a welcome surprise to receive, at the holidays or any other time: The number crunchers tracking the repair-and-maintenance job list for Hawaii’s public schools had been crunching the wrong numbers.

Once they discovered the error at the state Department of Education, the reality check emerged as crushingly bad news. The bottom line is that the work backlog will cost an estimated $868 million to finish.

That, said state Rep. Sylvia Luke, is about three times as much as what lawmakers were told last session. Luke, who chairs the House Finance Committee, has been clued into this for some months because she’s been working with the DOE. The big public reveal came last week, when the Honolulu Star-Advertiser published the update.

The bright spots: The public can more easily follow along now, with the launch of an online database; also, officials said, the agency has switched to a new contracting system that should reduce the delay in completion of some repairs.

And that’s fine. But those amendments don’t provide satisfactory answers to the two most burning questions: How could this have happened? And how will the taxpayer deal with such a costly burden, merely to return aging school facilities to basic health-and-safety conditions?

This must compel discussion by lawmakers and DOE heads for the 2019 session, to revisit priorities for project completion and make sure the most urgent fixes get funded first with what money is available.

Secondly, it would be wise for other state departments to review their own maintenance spending protocol to ensure that they are not similarly losing track of what needs handling.

Finally, the Legislature needs to have a serious conversation about what additional funding streams could be created to bolster the available resources for basic building maintenance.

The truly distressing chapter in the story is the disclosure of the previous, poor system for tracking projects. Items were checked off the pending list of repairs-and-maintenance jobs when initial funds were spent on them, even if it was just for design.

After that stage, information on the projects was scattered. Absent an automated system to track the jobs, they apparently fell off the radar screen.

However, the lack of a bang-up automated system falls far short as an excuse. Functional agencies and businesses manage such things with spreadsheets and rigorous accounting practices, which don’t include letting items get lost when work has barely started.

Dann Carlson, assistant superintendent for school facilities and support services, said his office had to comb through the system to assemble the full roster of 3,800 pending projects, broken into 11 categories.

The fattest class of jobs comprises the 696 roofing projects yet to be completed. If anyone needs a reminder of how crucial it is to stay on top of these things: Farrington High School’s auditorium roof collapsed six years ago during a heavy rainstorm. It was Nov. 23, 2012, a Friday, and it was lucky that nobody was injured.

Four years later, after nearly $12 million was spent, the auditorium reopened.

The condition of those hundreds of other roofs may not be as dire — a structural flaw at Farrington was cited as a factor in that collapse — but there are likely many old buildings among them, not in optimal shape, at best.

Getting a handle on this is the aim of the DOE’s rebooted maintenance program dubbed Future Schools Now, which the department unveiled in November.

It’s a revised method of contracting jobs that allows DOE to “contract several vendors through competitive bidding for commonly encountered projects over the life of a multiyear contract, rather than having to bid out individual jobs for repairs,” according to the department’s announcement.

One line of questioning from lawmakers this session should be to find out how widespread system deficiencies may be. In 2005, the Legislature passed Act 51, which placed construction and maintenance of school facilities under the DOE. Previously, the work had been handled by the Department of Accounting and General Services, which supervises most projects for state agencies.

Legislators should get a reading on how other agencies’ projects are being managed.

Officials had hoped that the DOE was “making a dent” in the work backlog, but it’s now plain that it hasn’t. It’s also plain that there’s not enough money available to do so.

This suggests the time has come to talk about new revenue streams for the DOE building inventory; roughly one-fifth is a century old or older, and there’s no way to cover that with existing resources. The debate over the proposed constitutional amendment last fall suggests that dedicating new revenue for building upkeep may be an easier sell than a new tax.

Regardless, some solution must be found. This concerns the safe accommodation of public school children. That qualifies as a “need to have,” if anything does.