Off-Street Parking Standards for the R-20 One-family Dwelling District in Arlington County
In the R-20: One-family Dwelling district of Arlington County, residential projects generally require one off-street parking space per dwelling unit, which increases to two spaces if the property fronts a cul-de-sac. Professional and institutional uses permitted within the R-20 district, such as medical offices, religious institutions, and schools, are subject to specific parking ratios based on floor area, seating capacity, or student enrollment. Most off-street parking in the R-20 district must be provided on the same lot as the primary use, though limited exceptions for tandem parking and setback encroachments apply to residential dwellings [§14.3.3, §14.3.7].
Residential Parking Requirements in the R-20 District
Residential parking standards for the R-20 One-family Dwelling district are primarily dictated by the type of street frontage and the specific nature of the residential development, such as the inclusion of an accessory dwelling or the use of Expanded Housing Options [§14.3.7].
General Residential Parking Ratios
For standard one-family detached dwellings in the R-20 district, Arlington County mandates the following minimum ratios:
| Use Type | Minimum Parking Requirement | Additional Requirements |
|---|---|---|
| One-family Dwelling (Not on cul-de-sac) | 1 per dwelling unit | Must be constructed and maintained per §14.3.3. |
| One-family Dwelling (Fronting cul-de-sac) | 2 per dwelling unit | Must be improved per §14.3.4.A and maintained per §14.3.3. |
| Accessory Dwellings | See Additional Requirements | 1 space must be created if none exist (unless a survey shows the block is <65% parked). If 1-2 spaces exist, they must be maintained. If >2 exist, at least 2 must be maintained. |
Expanded Housing Option (EHO) Parking
If an R-20 district property is developed under the Expanded Housing Option provisions of §10.4, the parking requirements are adjusted based on proximity to transit [§10.4.6.A]:
| Site Location | Minimum Requirement |
|---|---|
| Within 3/4 mile of a Metrorail station entrance | 0.5 per dwelling unit |
| Within 1/2 mile of a Premium Transit Network stop | 0.5 per dwelling unit |
| All other R-20 locations | 1 per dwelling unit |
| Note: Sites fronting a cul-de-sac must provide a minimum of 1 space per unit regardless of transit proximity. |
Commercial and Institutional Parking Requirements in the R-20 District
While the R-20 district is primarily for one-family dwellings, Arlington County allows certain non-residential uses by-right or via special exception. These uses must meet the following off-street parking standards [§14.3.7]:
| Use Type | Minimum Parking Requirement |
|---|---|
| Churches and Religious Institutions | 1 per 5 sanctuary seats. |
| Medical or Dental Offices/Clinics | 1 per 150 sq. ft. for first 5,000 sq. ft.; 1 per 200 sq. ft. for next 10,000 sq. ft.; 1 per 250 sq. ft. for area above 15,000 sq. ft. |
| Schools (Elementary and Middle) | 1 per 7.5 students (design capacity) for staff; plus 1 per 40 students for visitors. |
| Bed and Breakfasts | 1 per guest room, in addition to the spaces required for the principal residence. |
| Hospitals/Institutions | 1 per 4 beds, plus 1 per 2 employees (excluding staff doctors), plus 1 per assigned doctor. |
General Location and Design Standards
In the R-20: One-family Dwelling district, Arlington County enforces specific rules regarding where parking may be situated on a lot and how it must be accessed.
Parking in Setbacks
General regulations prohibit parking or required walls/curbs from encroaching on the exterior 10 feet of a setback area in residential districts. However, for one-family dwellings in the R-20 district, parking spaces are permitted to encroach on the exterior 10 feet of a setback if they are located on a driveway with an existing or approved curb cut [§14.3.3.E, §14.3.3.I].
Design and Delineation
- Dimensions: Standard parking spaces must be at least 9 by 18 feet for 90-degree parking, with a vertical clearance of at least seven feet [§14.3.3.C].
- Tandem Parking: Tandem parking is permitted for off-street spaces serving one-family dwellings in the R-20 district, provided they meet the standard dimensional requirements and do not encroach into the public right-of-way [§14.3.3.I.2].
- Surfacing: All parking areas and driveways in the R-20 district must be paved with a durable, dust-free, and hard material such as bituminous hot mix or Portland cement concrete [§14.3.3.I.1].
Sections Cited
- §10.4 Expanded Housing Option Development
- §10.4.6 Site development standards (EHO)
- §14.3 Parking and Loading
- §14.3.3 General requirements
- §14.3.4 Required improvements
- §14.3.7 Required parking and standing space
- §14.3.7.A Required parking table