The purposes of the Chain Bridge Road/University Terrace Residential House R- 21 zone are to:

  • Provide for areas predominantly developed with detached houses on large lots;
  • Preserve and enhance the park-like setting of the area by regulating alteration or disturbance of terrain, destruction of trees, and ground coverage of permitted buildings and other impervious surfaces, and by providing for widely spaced residences;
  • Preserve the natural topography and mature trees to the maximum extent feasible in a residential neighborhood;
  • Prevent significant adverse impact on adjacent open space, parkland, stream beds, or other environmentally sensitive natural areas;
  • Limit permitted ground coverage of new and expanded buildings and other construction, so as to encourage a general compatibility between the siting of new buildings or construction and the existing neighborhood; and
  • Limit the minimum size of lots so as to prevent significant adverse impact on existing infrastructure, especially on traffic and pedestrian safety, and to achieve the other purposes listed in this subsection.



The R-21 zone applies to the area bounded on the south by MacArthur Boulevard, on the east by Battery Kemble Park/Chain Bridge Road, on the north by Loughboro Road/Nebraska Avenue, and on the west by University Terrace.

The R-21 zone is mapped on a residential neighborhood, located at the edge of stream beds and public open spaces that have steep slopes, substantial stands of mature trees, and undeveloped lots and parcels subject to potential terrain alteration and tree removal.

Development Standards
Height (ft.) /
Stories 1
Minimum Lot Width (ft.) / Area (sq. ft.) Lot Occupancy Front Setback Rear Yard (ft.) Side Yard (ft.)2 Pervious Surface (min.)3 Zoning Regulation Reference
R-21 40 75 40% for lots < 6,500 sq. ft. A front setback shall be provided within the range of existing front setbacks of all residential buildings on the same side of the street in the block where the building is proposed. 25 8 50% Subtitle D, Chapter 13
3 7,500
(9,500 for lots created after July 20, 1999)
35% for lots > 6,500 ft. and < 8,999 ft. but not less than 2,600 sq. ft.
30% for lots > 9,000 sq. ft. but not less than 3,150 sq. ft.

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., not including the penthouse, 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.
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.
3 Provided the requirement shall not preclude enlargement of a principal building in existence as of July 30, 1999; or create nonconformity of a structure as regulated by Subtitle C, Chapter 2.