Density represents the number of dwelling units per net acre of land. Dwelling units include all residential units having sleeping, eating, cooking, and bathroom facilities, including single-family homes, mobile homes, townhouses, condominiums, duplexes (and other "plexes"), and apartment units. Net land area is calculated by taking gross acreage and subtracting undevelopable lands (e.g., wetlands) and the area in rights-of-way for streets and roads.