When Derek MacKenzie moved into his Brooklyn condo in 2022, his annual property tax bill was $140. This year, it ballooned to $7,600. Next year it is projected to hit $10,500.

The surge in tax reflects the end of an abatement his Park Slope condo enjoyed for roughly 15 years. Now that it's gone, MacKenzie and his condo neighbors pay full property taxes-a new financial reality for thousands of other New York City buildings whose tax breaks are going away.

"I knew it was coming," the 40-year-old said. "I don't think I fully understood how deep it would be."

Across the city's five boroughs, thousands of buildings are losing property tax abatements through 2030 and beyond. The Department of Finance puts that figure at roughly 4,100.

But some analysts using a slightly different methodology peg it much higher. The Roebling Index, a real-estate research and data platform, said as many as 4,800 condo, co-op and rental buildings could lose their tax breaks between 2023 and 2030 alone.

The phaseout means sharply increased taxes for roughly 66,000 residential units through 2030, the Roebling analysis found. An estimated 4,600 additional buildings covering about 94,000 units become fully taxable between fiscal years 2031 and 2040, according to the analysis.

Renters will feel the squeeze along with condo and co-op owners. About 2,630 rental buildings are phasing out of pre-2016 agreements by 2030, Roebling said. Some have rent-stabilized units that will become market-rate when abatements expire.

That exposes as many as 40,700 units to this rent-stabilization loss, Roebling found. Whether an individual apartment ultimately leaves stabilization will depend on required lease notices, applicable affordability rules and other regulatory agreements, said Corey Cohen, principal of the Roebling Team at Compass and publisher of the Roebling Index.

"But when a tax benefit expires, the additional cost has to be absorbed somewhere," he said, "through higher rents where regulation and the market permit, lower net income for the landlord or, over time, a lower property value."

New York City's affordability crisis was a crucial election issue that helped sweep Mayor Zohran Mamdani into office. He promised to freeze increases on rent-regulated apartments, and lower insurance costs for some property owners.

That won't help thousands of New Yorkers who have entered or will soon enter the phaseout period of the pre-2016 program, when developers were offered property tax breaks decades ago for housing-some with affordable components-as an incentive to meet demand.

The property tax abatements usually last anywhere from 10 to 25 years, but they decrease-typically about 20 percentage points-toward the end, until a building pays the full rate.

"When we purchased, they talked to us about the tax abatement," said Audrey Henry, a 59-year-old Manhattan co-op owner who bought her Harlem apartment in 2004. "They said, 'By the time it phases out, there will be a new program. Don't worry about it.'"

Henry and her neighbors live in a stretch of similarly abated co-ops and condos built around the same time as hers along the Madison Avenue corridor above 116th Street.

They have started a petition about what they call the looming "tax cliff" and organized outreach to local community boards. The boards sent letters to Gov. Kathy Hochul, Mamdani and his housing commissioner urging legislation that could lighten the tax burden for those buildings.

"It's not just property taxes-it's that on top of how unaffordable everything is," Henry said. "Everything costs more: water, insurance, wages, gas, you name it."

Henry's monthly maintenance also jumped to over $1,500 from roughly $1,000, just to cover building expenses. By the phaseout finale in 2031, her estimated property tax is approximately $10,000 a year, on top of whatever her maintenance will be.

"There's some folks who, after this year, may not be able to live here," said Henry, a widow who cares for her 98-year-old mother and has a daughter who is a freshman in college. "I hope I don't become one of them."

Selling a unit that's close to losing an abatement can be tricky, too. A citywide review of more than 37,000 condo sales found blocks nearing the end of the tax abatement appreciated 5.4 percentage points less than blocks where the benefit still had years to run, Cohen said.

A later version of the program extended the length of tax abatements and secured more affordable-housing requirements, and even construction-worker wage requirements on some large projects.

Some buildings aging out of older tax agreements can apply anew under the latest version, but getting approval usually carries additional requirements tied to affordability, construction and capital improvements and, in some cases, wages.

MacKenzie, who doesn't hold out hope for a new abatement for his Brooklyn condo, said he is resigned to paying hefty property taxes as the price of living in New York.

"It's something we have to consider as we plan out our long-term investment and retirement strategy and child schooling," he said.