The purposes of the Naval Observatory Residential House R-12 zone are to:

  • Promote the public health, safety, and general welfare on land adjacent to or in close proximity to the highly sensitive and historically important Naval Observatory in keeping with the goals and policies of the Federal and District elements of the Comprehensive Plan and the adopted Master Plan for that facility;
  • Ensure that public land within the zone shall be used in a manner consistent with the historic or ceremonial importance and special missions of the Naval Observatory;
  • Reflect the importance of the Naval Observatory to the District of Columbia and the Nation;
  • Provide additional controls on private land to protect Federal interest concerns, including the critical scientific mission performed at the Naval Observatory and the security needs of the Vice-President's residence; and
  • Provide development standards to reduce or eliminate any possible harm or restrictions on the mission of the Federal establishment within the zone.

The R-12 zone is intended to permit detached houses on moderately-sized lots.

Detached Dwelling Units
Height (ft.) /
Stories 1
Minimum Lot Width (ft.) / Area (sq. ft.) Lot Occupancy Front Setback Rear Yard (ft.) Side Yard (ft.)2 Previous Surface (min.) Zoning Regulation Reference
R-12 40 50 ft. 60%
(Places of Worship)
A front setback shall be provided within the range of existing front setbacks of all structures within an R-12 zone on the same side of the street in the block where the building is proposed. 25 8 50% Subtitle D, Chapter 7
3 5,000 40%
(All Other Structures)

Use Permissions Parking Inclusionary Zoning
Subtitle U, Chapter 2 Subtitle C, Chapter 7 Subtitle C, Chapter 10
R- Use Group A

1 Institutional buildings or structures may be erected to a height not exceeding 90 ft., provided that the building or structure shall be removed from all lot lines of its lot a distance of not less than 1 ft. for each foot of height in excess of that authorized in the zone in which it is located.
the height of a building shall be the vertical distance measured from the level of the curb opposite the middle of the front of the building to the highest point of the roof or parapet; and the curb elevation opposite the middle of the front of the building shall be determined as the average elevation of the lot from its front line to its rear lot line.
For a building subject to a side yard requirement, but which has an existing side yard less than 8 ft. wide, an extension or addition may be made to the building; provided, that the width of the existing side yard shall not be decreased; and provided further, that the width of the existing side yard shall be a minimum of 5 ft..