The really monstrous thing about the “monster homes” — the structures built to the limits of the lot size, straining the capacity of some Oahu residential communities — is that there was a way to stop them from being built.

Unfortunately, the city agency in charge of regulation has failed to do its job.

That’s the main takeaway from an audit of the city Department of Planning and Permitting, concluding that DPP “does not effectively manage building permits and inspections related to large, detached dwellings.”

Acting City Auditor Troy Shimasaki rightly cut very little slack for the agency, while identifying certain systemic shortcomings, such as the lack of computerized means of tracking the mountains of data involved in permitted construction.

To answer concerns that DPP malfeasance allowed these projects, the audit did attempt but was unable to confirm allegations of “fraud, abuse or conflicts of interest” among the staff.

Regardless, any database as opaque as the one in DPP would enable corruption to be hidden from view, the auditor said: “We acknowledge that it was highly unlikely that we would find such evidence present in the department’s collection of files and information without direction and input from people familiar with or involved with the alleged wrongdoing, abuse, or conflicts.”

That’s precisely the point, and it’s why overhauling the agency’s filing system has to be a priority issue for the mayor, and for anyone who hopes to replace him in next year’s election.

And as excuses go, the old information-technology issue, a known deficit that’s rampant throughout Hawaii government bureaucracies, falls flat.

The administration has declined to comment beyond the written response by city Managing Director Roy Amemiya, appended to the audit. Amemiya noted the agency’s chronic staffing shortage, and pointed to plans to convert to a web-based permit review software. That should move quickly. There are working systems already in operation in myriad cities, so there’s no need to reinvent the wheel.

Even lacking a 21st-century IT solution, there were low-tech ways to head off the monster homes. One was basic surveillance: There were a few builders responsible for a lot of these projects, and it should have been possible to flag them as high-risk — or to deny their permits outright.

Some of that surveillance has been done independently. The Hawai‘i Construction Alliance, the group representing building-industry unions, crunched its own data last year to find a single company, HH Constructions Inc., with 17 notices of violation from DPP.

Surely it should be possible to head off at least the problems caused by a frequent, known offender.

Further, the city has failed to impose fines and penalties to the full extent, according to the report, and that does nothing to communicate its resolve to enforce its rules — or to deter others’ bad behavior.

In response, Amemiya wrote that the city “may be recommending an increase to triple the normal fee” for applications submitted after work has begun. That would be a start.

The agency objected to some recommendations, including one to cancel applications for projects missing deadlines. Amemiya said such a crackdown ignores “individual cases of hardship” and DPP’s goal to provide “customer service.”

But if the staffing shortage is so bad, it makes sense to winnow the backlog of work by curbing projects that are not ready and quickly shutting down those that flout the rules.

The city indeed owes good customer service — to the competent builders, and to the residents of Oahu who want to live in well-planned communities, not neighborhoods that are hemmed in by monstrosities.