Basement vs cellar
The two spaces aren’t the same.
| Definition | |
|---|---|
| Basement | A story partly below curb level but with at least half of its height above curb level |
| Cellar | An enclosed space with more than half of its height below curb level; cellars usually have windows too small for an adult to fit through |
Basements and cellars in residential buildings of any size can’t be lawfully rented or occupied unless they meet minimum light, air, sanitation and egress requirements and are approved by DOB. Cellars in one- and two-family homes can never be lawfully rented, and can’t be used for sleeping, eating or primary living.
Requirements
What a legal basement apartment needs.
- A valid Certificate of Occupancy that covers the basement
- Minimum 7-foot ceiling height
- At least one window in every room, with the bottom of any required yard or open space no more than six inches below the window sill
- Rooms that meet Housing Maintenance Code minimums
- Damp- and water-proofed walls at ground level if conditions require it
In a two-family home, a basement can’t be rented if doing so would make the building a multiple dwelling that needs a new Certificate of Occupancy.
If it’s illegal
The risks of an illegal unit.
- Safety hazards such as carbon monoxide poisoning, poor light and ventilation, and limited escape routes in a fire
- HPD and DOB can both inspect, issue violations and order occupants to vacate
- Owners can be charged for city costs, including relocation services for the occupants
A pilot program run by HPD offers loans to eligible low- and middle-income homeowners in East New York and Cypress Hills, Brooklyn, to convert a basement into a legal apartment.
Thinking about legalizing a unit, or got an illegal-occupancy violation? Call us and we’ll review the filings it takes.
Call (929) 367-0962Questions
Frequently asked.
Can I rent out my cellar?
Not in a one- or two-family home. Cellars there can never be lawfully rented or used as primary living space.
How do I know if my basement is covered by a CO?
Look up the property’s Certificate of Occupancy on the DOB website and see whether it includes the basement. Our guide to finding a CO shows how.
Who enforces illegal apartments?
Both HPD and DOB inspect for illegal occupancy and can issue violations or Vacate Orders. 311 handles complaints.
Sources
Official sources.
General information about New York City procedures, last reviewed November 2026. Amounts and rules change and every property is different, so this isn’t legal advice. Call us about your specific situation.