The last thing taxpayers want to hear after a long lobbied-for, necessary state project is completed is, “Here we go again.” But here we are, again — confronted with an unanticipated, outsized expense and revelations that expected standards weren’t met after a project has been delivered.

This time (again) the painful news that a project didn’t go as planned comes from operators at the high-security Hawaii State Hospital, designed and built by private contractor Hensel Phelps at a cost of $160 million.

It’s too late to fix the flaws in construction contract development, awards and monitoring that brought Hawaii to this point in this case, but the inadequate practices that have made these kinds of expensive disappointments too common must not be allowed to continue.

Almost immediately after the project was purportedly completed four years ago — and work was accepted by the Department of Accounting and General Services (DAGS) — staff discovered initial, obvious problems, forcing a delay of more than a year before patients could be moved in.

The state Department of Health (HDOH) is now seeking $6.2 million from the Legislature for emergency repairs, along with $2 million for legal expenses as state attorneys attempt to “resolve” ongoing problems traced to the hospital’s construction by Colorado-based Hensel Phelps. These include mold, corrosion and an ineffective air-handling system.

Other, major repairs — replacement of the hospital’s leaky roof and extensive plumbing fixes, needed just three years after the hospital’s opening — will cost another $28.8 million, also sought from the Leg, albeit as a less urgent appropriation.

On Wednesday, HDOH and other state agency officials briefed members of the state House Committee on Health about conditions at the State Hospital, which serves 144 acute psychiatric patients. Unsettling matters further, officials said the $35 million in estimated total repair costs could go higher.

Gordon Wood, a state deputy public works administrator, said problems include plumbing leaks and an ineffective and corroding ventilation system, along with roof drain designs that were changed by the contractor and don’t work properly.

Disturbingly, Wood said corroded metal window louvers in the facility’s gym have dropped shards he described as “little daggers.”

Perhaps more worryingly, Wood related, “Somehow a contractor thought that it was reasonable to just pour grout into the drains. And you know, they don’t work very well after that.” The tile grout clogged drain pipes, but state workers couldn’t uncover the cause until they “started to dig into the building and … tear things apart.”

Without question, emergency repairs must be done for the safety of hospital patients and staff. Senate Bill 1448, appropriating about $6.2 million to identify water leaks, continue mold abatement and repair the building’s air-circulation system, and an additional $2 million for legal costs, was properly advanced on Feb. 3.

J.T. Kim, a state deputy attorney general, said Hensel Phelps has been doing corrective work on the building at its own expense. But serious problems persist, including mold growth that’s led staff to file collective-bargaining grievances.

State lawyers, HDOH and DAGS say they are seeking to hold “all responsible parties” accountable for alleged design and construction defects. However, there has been no definitive assignment of responsibility, and it’s not yet settled whether the state can or will be reimbursed for this extensive repair work. That in itself is unacceptable.

As legislators demanded at Wednesday’s hearing, better explanations as to how we got here from HDOH, DAGS and Hensel Phelps must be provided. Assurances that state agencies have developed procurement processes that won’t leave taxpayers holding the bag for shoddy, negligent or incomplete work by private contractors, whatever the endeavor, are also needed.