Finding a rent-stabilized apartment in New York City can be difficult. But housing advocates say many renters may already be living in one without realizing it.

A new city law, known as the Rent Transparency Act, aims to change that by requiring landlords to clearly notify tenants when rent-stabilized units exist in their buildings.

For Williamsburg resident Harold Joyce, that information came only after his landlord raised his rent by $500.

Joyce, who has lived in his apartment for 16 years, said the increase prompted him to look into the building’s status. He later learned the property had received a J-51 tax abatement, which requires apartments in the building to be rent stabilized.

“The landlord had applied for a J-51 tax abatement that essentially stabilizes the entire building,” Joyce said. “And he wanted to chase us out before they were stuck with us.”

Under the new law, landlords must post notices in common areas stating that rent-stabilized apartments are present in the building. The signs must be written in both English and Spanish and include information on how tenants can check whether their individual units are rent stabilized.

City Councilmember Sandy Nurse, who sponsored the legislation, said the measure is intended to prevent illegal rent overcharges and keep tenants informed of their rights.

“We want to make sure that people know they’re stabilized, know their rights and aren’t illegally overcharged,” Nurse said.

Nurse said the issue is personal for her, recalling that she did not realize her own apartment was rent stabilized until a housing organizer knocked on her door.

Housing advocates say lack of transparency has long allowed some landlords to misrepresent units, contributing to displacement in a city already facing an affordability crisis.

Joyce said learning the truth about his apartment made it possible for his family to remain in New York City.

“We wouldn’t be able to live in New York,” he said. “We wouldn’t have been able to do this without access to affordable housing.”

The Rent Transparency Act takes effect Jan. 23.