The last few days of December are typically quiet for Lidia Leszczynski, Montclair’s tax collector, but this year is different.

With a new federal tax law set to take effect Monday, residents are bombarding her office with calls and emails asking to prepay next year’s property taxes before they lose the ability to deduct the entire bill on their federal taxes.

“The phones are ringing off the hook,” said Leszczynski, adding that Montclair will open the Tax Collector’s Office for five hours Saturday to meet the demand. “It’s all the phone calls we’ve been getting about the next tax law.”

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New Jersey homeowners have good reason to be nervous about the Tax Cuts and Jobs Act, which caps at $10,000 the amount of state and local taxes they can deduct on their federal income tax return.

The law, approved last week by Congress and signed Friday by President Donald Trump, is another millstone hung from the necks of Garden State residents, who already have the highest property taxes in the nation.

Overall, roughly half of Bergen and Essex County homeowners already pay more than $10,000, as do between 35 and 40 percent of those in Passaic and Morris counties.

Homeowners in the region’s most-heavily taxed towns — like Montclair, Ridgewood, Tenafly, Alpine, Millburn or Saddle River — are set to be hit the hardest.

On Wednesday, Gov. Chris Christie signed an executive order requiring municipalities to credit early payments, which must be postmarked on or before Dec. 31.

“The action I took today will ensure that local governments are flexible and accommodating of their local property taxpayers as we transition to the new federal tax code for 2018," Christie said in a statement from his press office. "This executive order requires local officials to dedicate the resources and staffing to serve New Jerseyans who are planning in this way for their families and their futures."

Christie supported the federal tax law despite its expected effect on New Jersey.

Can I deduct my property taxes?

If residents have enough cash on hand to prepay next year’s property taxes, then doing so could make sense, according to the New Jersey Society of Certified Public Accountants.

“Having the ability to prepay some of one’s 2018 tax bill is a plus for some constituents and could result in savings in their overall federal tax bill, but not everyone will be so lucky,” Ralph Albert Thomas, the group’s CEO and executive director, said in a news release. “It will depend on one’s own financial situation.”

The IRS said Wednesday that some homeowners who prepay local property taxes due in 2018 will be able to claim the deduction on this year's returns, but only if the taxes have already been assessed and billed. People can't guess at what next year's assessment might be, pay it now and claim a deduction for that amount.

"A prepayment of anticipated real property taxes that have not been assessed prior to 2018 are not deductible in 2017," the IRS said on its website.

In Tenafly, Mayor Peter Rustin said there was increased traffic at the Tax Collector’s Office last week as residents stopped in to prepay or ask questions. The average borough home is assessed at about $803,000, and homeowners pay nearly $20,000 in annual property taxes, according to the state’s Department of Community Affairs.

But Rustin stopped short of recommending residents prepay — despite the apparent benefits — and echoed the accountant society’s comments.

"Tenafly is accepting prepayment. However, our recommendation is that you check with your accountant because, for some people, there may not be any benefit to doing so,” Rustin said. “It all depends on your tax situation."

New tax law polled poorly

The federal tax law, approved by congressional Republicans without a single Democratic vote, has polled poorly. According to a Monmouth University Poll released Dec. 18, only 26 percent of Americans approved of the plan, while 47 percent did not.

Democrats have attacked the GOP-led effort as a giveaway to businesses and the wealthy. Republicans say Americans will support the law when they see its effects — namely, more money in their paychecks. Tax cuts for individuals expire in 2025.

Nearly all the members of New Jersey’s congressional delegation voted against the bill. Rep. Tom MacArthur, a second-term Republican from Toms River, lent his support after House leaders abandoned their initial plan to entirely eliminate state and local tax deductions.

Property tax deductions in N.J

In Ridgewood, Mayor Susan Knudsen said the village is accepting early payments, as several residents requested. The average village home, assessed at about $694,000, comes with a property tax bill of more than $17,000 annually.

Municipal workers have been “quite busy” processing prepayment requests, noted Knudsen.

In Fair Lawn, where homeowners pay more than $10,000 in property taxes on the average assessed home of $326,000, Mayor John Cosgrove said there has been interest in prepaying.

“People have been asking,” Cosgrove said. “Our auditor said they can do it. Under the new tax law, it seems like it would help residents save money, so if people want to prepay we'd be glad to let them take advantage of that."

John Labrosse, the mayor of Hackensack, said the city is letting residents prepay the first two quarters of their 2018 taxes. The city may extend the tax collector’s hours if demand is high, he said.

“We haven’t made any plans to stay open the weekend yet,” Labrosse said. “We’re going to base it on need … If there’s a need, we’ll take care of it.”

Hackensack homeowners pay nearly $8,000 on the average house, assessed at about $234,466.

Michael McPartland, the mayor of Edgewater, said there has been a marked uptick in deposits over last year.

“It’s not a mad rush to the door, but there is definitely a big, significant rise,” McPartland observed.

Email: janoski@northjersey.com

Staff writers James Nash, Melanie Anzidei, Ricardo Kaulessar, Michael Curley, Deena Yellin, Nicholas Katzban and Rodrigo Torrejon and the Assocaited Press contributed to this report.