“My wife says I have a fault of believing in government,” Assemblyman Michael Benjamin told us the other day when we asked what his thoughts on the filtration plant were these days.

He was referring to the promises, most now broken, made to him and his colleagues by city officials when seeking the Assembly’s support for building the plant in Van Cortlandt Park.

Kennedy Benjamin might have missed her calling. Her critical eye would have helped save city taxpayers from footing the bill for what is increasingly being considered a public disaster.

Still, credit is due the assemblyman and one of his colleagues, Ruben Diaz, who have admitted that Jeffrey Dinowitz was right when he warned that building a filtration plant in a public park would not yield Bronx jobs and would not cost less than building it in Westchester.

Healthy skepticism has been in short supply for Bronx elected officials who have bought into two big, dumb projects on the basis of being told what they want to hear, rather than on what can be documented and legally enforced. (The other is Yankee Stadium, though there has been some progress of late holding off those horrendous parking garages.)

Diaz and Benjamin say that the next time the city and developers come a courtin’ they won’t be as easily taken in. We shall see.

But is all this self-reflection a waste of time, considering the job is well under way?

Not if it leads to a constructive investigation.

“If costs have escalated because of incompetence or worse, then we need to prevent that from continuing to happen on this project and from happening on other projects,” Dinowitz said.

The assemblymen and any additional colleagues they can recruit (Dinowitz is working on that) can ask Assembly Speaker Sheldon Silver to hold hearings in the appropriate committee. Silver is unlikely to want to reopen the debate on a project that divided his caucus, but if a good chunk of the same Bronx delegation that championed it asks for hearings, he’ll have a harder time fending it off.

Dinowitz also thinks a City Council hearing would be a good idea. When it met a couple of weeks ago, the Croton Facilities Monitoring Committee (FMC) did not put forth a resolution calling for a hearing, but committee chair Greg Faulkner said he would support it if someone proposed it.

Faulkner says he is more focused on the jobs issue and feels that more will come from that than an investigation of the costs.

But it seems that the FMC, which has no real power except to ask questions, is not making much headway on its own extracting the jobs that were promised to Bronxites by unions and city officials. Maybe a Council hearing would help things along.

At an FMC meeting a couple of weeks ago, union officials put up all kinds of verbal roadblocks, saying they had to go by the “list,” and that while they do give out apprenticeships, the trades needed on the project are very difficult and need a lot of training. The rank-and-file members who spoke had a similar message for new workers. In a nutshell: This is hard and dangerous work. Stay away.

The question then, of course, is why were these jobs promised in the first place?

So, community leaders, activists and elected officials can disagree on what part of this fiasco riles them most.

But it seems clear to us that all of them need to be investigated. Maybe then the lawmakers doing the investigating-most of whom supported this project-will acquire the kind of healthy skepticism Kennedy Benjamin was born with.