Maria Wells said she never intended to be a landlord. She sells real estate; she doesn't invest in it. Now the Florida resident owns two properties. One was her son's, but he had to move to take a new job.

The other was hers, but she got married and moved in with her husband. She can't sell either because she is underwater on both mortgages, so she rents them. Maria is one of a growing cadre of what the Realtors have dubbed, "Accidental Landlords."