The legalization of a basement in New York City can be a complex process, but here there are some general steps to follow.

Verify the zoning regulations of your property to determine if your basement is eligible for conversion. In some cases, basements may not be eligible for conversion due to zoning restrictions or other factors. The city uses zoning to group land in different areas, or areas, with different norms about what can be built in each of them.

After being clear about the zoning of your home, obtain the necessary permits from the New York Buildings Department (Dob) for conversion work. This may include a construction permit, electrical permit, plumbing permit and others, depending on the scope of work. 

At this point it is important to hire an architect or license to prepare plans and drawings for conversion. They will ensure that the plans comply with construction codes and regulations. 

Complete the construction work according to the plans and specifications, ensuring that all the work is carried out to the code to the closing of the project obtain an occupation certificate. Once the work is completed, obtain an occupation certificate (CO) of the Dob. The CO confirms that the conversion work has been done to encode and that the basement is now a legal life. 

Throughout the process, the DOB will schedule inspections to ensure that the work is being done to encode. Be sure to program these inspections in advance and make the necessary corrections before the next inspection. After obtaining the CO, it is important to monitor the Dob and make sure that the records of your property are updated to reflect the legal basement. This will ensure that you do not receive any violation or penalty in the future. 

It is important to keep in mind that the process to legalize a basement can vary according to the details of your property and the scope of work. It is a good idea to consult with a licensed professional and the New York buildings department to ensure that it is following all the necessary steps and comply with the regulations.