There are between 10,000 and 38,000 potential basement apartments in New York City, according to a study by Citizens Housing and Planning Council, a non-profit research and education group focused on housing in New York.

Sarah Watson, deputy director at the council, says there are a lot of advantages to creating a legal basement rental unit. “You don’t have to acquire the land, you don’t have to increase the size or shape of the home,” Watson said, and “adding a rental unit to their revenue for the month can really save them from losing their homes.”

Read more in WNYC.