Housing Opportunities Commission, adjusts Maryland State Delegate Lorig Charkoudian's hardhat during a groundbreaking ceremony for the Hillandale Gateway housing development in Silver Spring, Md. The HOC says it owns more than 9,400 apartment, townhome and single-family home rental properties and provides subsidized housing for more than 9,300 households.'/>Maryland's Montgomery County is building mixed-income apartments in which people who can afford to pay market rate allow other renters to pay less. Cities and states nationwide are taking up the idea.(Image credit: Alyssa Schukar)