BERGENFIELD — What could possibly go wrong?

As part of a much-hyped trash collection program implemented last year, residents were to be given garbage cans based on the number of bedrooms in their homes. But borough officials soon realized they had a problem on their hands: Residents were claiming far more bedrooms than tax records showed they were supposed to have.

That discovery has had significant consequences. Borough officials now say nearly 200 property owners owe more than $800,000 in back taxes, because they were not assessed for building projects ranging from a two-room addition to new homes.

While an investigation of the borough's tax assessor and Building Department is ongoing, property owners have been told that they must pay up by Tuesday.

"I think it's extremely unfair," said Gila Elbaum, a Cameron Road resident who is on the hook for $4,891. "Who's to say you have that kind of money?"

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How so many properties could have gone under-assessed is not yet clear. The affected property owners were issued building permits to make improvements to their commercial buildings and homes, but officials say the work they were doing was not being tracked.

Once building improvements are completed, borough properties must be inspected and certificates of occupancy issued. Added assessments are put on the tax roll after the tax assessor gets those certificates from the Building Department.

Michael Ravenda, the head of the Building Department, said he could not speak for what happened there before he was promoted to his current role last year.

"I can only tell you we've worked very hard to get things running the way they should," Ravenda said.

Since the issue was uncovered, Ravenda said, he and his staff have rifled through every file in his office to find building permits — some dating as far back as 1999 — that remained open.

"My girls couldn't put their fingers in the files without breaking their fingernails because it was so packed in," Ravenda said.

Zoning officer Harry Hillenius, who was interim head of the Building Department until Ravenda took over, declined to comment. Kenneth Pfannen, who preceded Hillenius and retired in May 2015, did not return a call placed to his home on Wednesday.

George Reggo, the tax assessor, said many added assessments were unaccounted for because he did not get certificates for them.

"I got some, but the ones I didn't get, I couldn't put on," Reggo said.

Former Bergen County Prosecutor John Molinelli was hired in September to review operations of the Building Department and Tax Assessor's Office. That investigation is not yet completed.

But an analysis by Glen Rock-based Appraisal Systems Inc. has determined that 172 property owners were under-assessed. The exact amount of unpaid taxes is likely in the millions, say borough officials, but state law limits the town to recouping just two years of lost revenue.

That brings the total sum due the tax collector from affected property owners to $801,011.

Many of the property improvements in question, such as renovated kitchens and new dormers, were relatively minor, according to a report by the appraiser. Others, such as add-a-level makeovers and construction of swimming pools, were larger in scope.

Some added assessments that slipped through the cracks were for entire homes.

An example may be found on Hallberg Avenue, where an owner of a home assessed at $423,500 — $103,500 above the borough average — should have been paying roughly $13,400 in annual taxes, but according to the report, was not. He or she now must pay more than twice that amount by next week's deadline.

A Baker Avenue man, who wished to remain anonymous, owes $11,335. He said he had to sell much of what he accrued in liquid assets to pay the extra taxes, and he intended to ask for an installment plan.

"I don't have that much in savings," he said. "I don't think we should be punished because they were negligent."

Borough Attorney John Schettino said payment plans cannot be arranged. Property owners would have to go though a legal process similar to a tax appeal, he said, to work out a payment schedule.

"It's not within the authority of the governing body to do that," Schettino said.

Another resident, Richard Bon, said he made a modest addition to the Greenwich Drive home he shares with his wife, Lynn. He must pay $691 in back taxes.

"I'm one of the lucky ones — I'm lucky I can afford it," said Bon, who owns a pest-control company. "But there are a lot of McMansions going up. I can see those people being really upset."

Borough Administrator Corey Gallo expressed a different sentiment.

"The dust settled," Gallo said. "From my perspective, I'm happy we were able to recover $800,000 in taxes."

Gallo said officials are taking steps to improve accountability and organization at Borough Hall. For example, he said, employees in the Building Department now get reminders on their computers to prompt them when improvements to commercial buildings and homes are due for inspections.

"If they don't call us for inspections, we're calling them," Gallo said. "That never happened before. That's the proactive stuff we're doing — the measures we're taking — to ensure this doesn't happen anymore."

But Ravenda said property owners should share responsibility for checking that their building permits are closed.

"If I put an addition on my house — if I put a second floor on my house — I know I'm not paying taxes because my taxes didn't go up," Ravenda said. "There's got to be a reason why that's happening."

Email: devencentis@northjersey.com

CONTACT US: Were you one of the 172 under-assessed property owners? We want to hear from you. Contact Staff Writer Philip DeVencentis at devencentis@northjersey.com