In a crackdown on some of the worst landlords in New York City, housing officials have identified 200 of the most poorly maintained apartment buildings and are renewing efforts to force owners to repair hazardous conditions.

The Department of Housing Preservation and Development compiled a list of 200 buildings that have 27 or more of the most serious housing code violations and an average of five or more such violations per unit. The citations — for problems like minor leaks and hazardous conditions like lack of heat or hot water — were issued in the past two years, and the owners have either failed to correct the problems or failed to notify the city that they have.

The 200 properties are the first to be identified in the agency’s Alternative Enforcement Program, which was created this year under the new Safe Housing Law (legislation spearheaded by Make the Road New York) and is designed to put increased pressure on landlords to bring thousands of run-down buildings into compliance with the housing maintenance code.

The majority of the listed buildings — 132 — are in Brooklyn. The Bronx had the second most, 52. Many of the buildings are small residential properties, with fewer than 15 units. Visits to a handful of the buildings yesterday illustrated the bleak conditions facing many low-income families. Some tenants had broken stoves and could cook only on electric hot plates. Others lived with gaping holes in bathroom ceilings, mold on the walls, water leaks, faulty electrical connections and rats.

The owners have four months to correct all violations relating to heat and hot water, and at least 80 percent of the other violations. If those repairs are not made and any charges owed the city are not paid within four months, the city has power under the new law to overhaul entire building systems, such as heating and plumbing, and to force the owners to pay for the work. Failure to pay for either the repairs or additional fees could result in a lien being filed against the property.

At 531 Knickerbocker Avenue in the Bushwick section of Brooklyn, the front door of the peach-colored brick building was open yesterday. It had no door knob and an empty square where a small window used to be. The second door behind it was open, too. It had a door knob but no lock. Tenants said they were taking up a collection to have the locks installed, because the management had not responded to their complaints.

The building has only eight units, but 202 serious and immediately hazardous violations. Attempts to reach the owner — a limited liability corporation called ASB 531, according to tax records — were unsuccessful.

In Apartment 4L, Amalia Perez, 50, said workers removed her broken refrigerator months ago and never gave her a new one. Family members bought her a small one she keeps in her bedroom. She said the heat and hot water recently started working in her four-bedroom apartment. She used to boil water to take a bath, but had to use an electric burner because her unit had not been getting gas.

"It’s been hell," said Ms. Perez, who lives on public assistance and said she could not afford to move. "Not even an animal got to live like this."

At 1820 Grand Concourse in the Bronx, a 29-unit building that had 347 violations, a sign affixed to a mural in the lobby warned that the building contained potentially dangerous lead-based paint. Tenants complained of leaks and rats "bigger than cats," as one longtime resident described them.

Larry Rukaj, who works for Prestige Real Estate Services, the managing agent, said his company took over the building a couple of months ago. He blamed some of the tenants’ failure to pay rent for the building’s neglect. "I know it has a lot of violations, but we’re working on it," Mr. Rukaj said.

The building with the most violations in the program is at 1055 University Avenue in the Bronx, a 94-unit property with 1,413 violations. Yesterday, workers moved construction materials through the lobby, working on renovations. Raymond Ortiz, 28, who recently took over as the building’s superintendent, said the number of violations would be down significantly by the end of the month.

"I’ve been talking to all the tenants, and I’ve been trying to get as many complaints as I can," he said.

Some tenants said they had not had gas for four months. Chris Maldin, 72, had so much water leaking into his apartment during a heavy rain that he was forced to sleep in another room, waking up every two hours to empty the water that had collected.

Last year the city’s housing agency sued the owner, Highbridge Apartments LLC, in Bronx Housing Court, and the agency later brought a contempt case against it after a reinspection. A representative of Highbridge Apartments declined to comment.

Shaun Donovan, commissioner of the Department of Housing Preservation and Development, said the agency’s lawyers had sued a number of the buildings’ owners to improve the conditions. "These buildings are frequent customers in the enforcement area," Mr. Donovan said.

City officials plan to release the list of the 200 properties formally today. Last week, notices went out to the landlords.

In addition to the violations, the listed buildings are also those that owe the city for unpaid emergency repairs. The 200 properties collectively owe the city nearly $2.4 million in repair charges. The building in Brooklyn at 531 Knickerbocker Avenue owes $87,709, the most of any of the buildings listed.

The new enforcement approach has broad support from low-income housing advocates as well as the Rent Stabilization Association, a group representing residential landlords and managing agents.

"This may be the first time in the city in which we had a piece of legislation supported by H.P.D., the Council, the leading tenant advocates and the leading landlord representatives," said Christine C. Quinn, the City Council speaker.

David Hirschman contributed reporting.