NYC Duplex vs LA Duplex

When I talk to clients in New York City about a duplex we are discussing a two-story apartment, condo, or co-op.  It’s in a building with a staircase to a second floor of living space within the walls of the unit.  Here in L.A. when we say duplex we mean two legal residences on one parcel.  A common version is one structure with two mirror image, side-by-side units.  It can also be one structure with a bigger and a smaller unit or two individual free standing buildings.  Regardless of the configuration of the two units, there is only 1 APN or assessor’s parcel number, 1 mortgage, and 1 grant deed.  A duplex can be bought by two people but they will share ownership and share a mortgage just as if they’d purchased a single family home together.  If done right it can be a great condo alternative for two individuals or a way for someone to bring down their monthly costs by living in one side and renting out the other.