302.1 In the low-density R zones, density is established as a single principal dwelling unit per lot. In those low-density residential zones that are limited to a single principal dwelling per lot, a single accessory apartment may be permitted per principal dwelling subject to conditions.

302.2 In the moderate-density RF zones, density is established as a maximum number of principal dwelling units per building, and in certain cases, through the number of principal dwelling units per minimum land area.

302.3 Occupancy of a principal dwelling unit is based on a household, unless otherwise permitted within a zone.

SOURCE: Final Rulemaking published at 63 DCR 2447, 2650 (March 4, 2016 – Part 2).