 It has resulted in developments that were and are ethnically and even economically diverse as some of the original tenants became more successful (and therefore pay a surcharge) while others found themselves closer to or in poverty.The tenants have formed stable communities that in some cases (such as on the Upper West Side of Manhattan) have resulted in substantially increased property values.Landlords generally may remove the developments from Mitchell-Lama by prepaying the mortgage, which usually happens 20 years after the project is developed.