The city’s ability to crack down on chronically delinquent landlords is set to expand with the passage of a City Council bill targeting the most distressed buildings in the city for mandatory repairs.

Under the legislation, called the Safe Housing Act, the city will identify the 200 worst buildings in New York each year based on outstanding housing code violations, the ratio of violations to apartments, and the ratio of outstanding emergency repair charges paid by the city to apartments.

Owners of targeted buildings will be required to provide tenants with heat and hot water and fix at least 80% of hazardous violations within four months. If owners do not make the required repairs, the Department of Housing Preservation and Development will pay for an outside contractor to do the work and then will send the bill to the landlord.

If landlords refuse to foot the bill, the city will take over the property and put it in an appropriate housing program, Speaker Christine Quinn said yesterday, though she added that the city does not want to become a landlord.

The council also approved a bill yesterday requiring certain building owners to file a list of the floor number with the Fire Department. In some city buildings the posted floor number is not the same as the actual floor it is situated on.