Duplex and Multi-Family Townhome Allowances in Arlington County
In Arlington County, duplexes and townhouses are permitted by-right in the R2-7 district and through site plan or use permit approval in the R-10T and R15-30T districts. Additionally, the Expanded Housing Option (EHO) allows for duplexes, semidetached units, and small multi-family townhomes (up to 3 units) in the R-5, R-6, R-8, R-10, and R-20 districts subject to specific site area requirements and a maximum of 35 feet in height. All Residential Apartment (RA) and several Commercial/Mixed Use (C) districts also permit these housing types either by-right or via special exception.
Residential Zoning Districts (R)
In the Arlington County residential hierarchy, the allowance for duplexes (two-family dwellings) and townhouses depends heavily on the specific district sub-classification. While lower-density districts like R-20 and R-10 primarily focus on one-family detached dwellings, higher-density residential zones provide broader allowances.
Standard District Allowances
The following table outlines the permissions for duplexes and townhouses within the Arlington County Residential (R) districts:
| District | Duplex / Semidetached Permission | Townhouse Permission | Height Limit (By-Right) |
|---|---|---|---|
| R-20 | No (Except EHO) | No (Except EHO) | 35 feet |
| R-10 | No (Except EHO) | No (Except EHO) | 35 feet |
| R-10T | Site Plan Approval (S) | Site Plan Approval (S) | 35 feet |
| R-8 | No (Except EHO) | No (Except EHO) | 35 feet |
| R-6 | Special Exception (U/S)* | No (Except EHO) | 35 feet |
| R-5 | Special Exception (U/S)* | No (Except EHO) | 35 feet |
| R15-30T | Site Plan Approval (S) | Site Plan Approval (S) | 35 feet |
| R2-7 | Permitted By-Right (P) | Permitted By-Right (P) | 35 feet |
*Note: Special exceptions for duplexes in R-5 and R-6 are generally restricted to transitional sites abutting RA, C, or M districts or located on arterial streets [§5.1.2, §5.1.3].
Residential Apartment (RA) Districts
The Arlington County Residential Apartment districts are designed for higher-density housing. Duplexes, semidetached units, and townhouses are widely permitted in these zones, often alongside larger multi-family structures.
- RA14-26, RA8-18, RA7-16, and RA6-15: All these districts allow duplexes and semidetached dwellings by-right (P) or by site plan (S). Townhouses are allowed by-right in all RA districts except RA7-16, which requires site plan approval for townhouse developments [§6.1.2].
Commercial and Mixed-Use Districts (C)
Several Commercial/Mixed-Use districts in Arlington County permit residential uses, including duplexes and townhouses, to encourage vibrant transit-oriented development.
- RA4.8, R-C, RA-H, and RA-H-3.2: These districts allow duplexes and semidetached units by-right or via site plan. Townhouses are also permitted by-right in RA4.8, RA-H, and RA-H-3.2 [§7.1.2].
- C-2 (Service Commercial): This district allows duplexes, semidetached units, and townhouses by-right [§7.1.2].
- C-TH (Commercial Townhouse): As the name implies, this Arlington County district is specifically designed to encourage commercial structures with the physical characteristics of townhouses [§7.18.1].
Expanded Housing Option (EHO) Development
Arlington County established the Expanded Housing Option to increase the range of housing choices in traditionally single-family neighborhoods. This allows for the creation of duplexes and townhouses in districts where they were previously prohibited.
EHO Applicability and Standards
EHO developments are permitted in R-20, R-10, R-8, R-6, and R-5 districts [§10.4.2]. The following standards apply to EHO projects:
| Standard | Duplex Requirements | Townhouse Requirements (Max 3 Units) |
|---|---|---|
| Min. Site Area (R-20) | 20,000 sq. ft. | 20,000 sq. ft. |
| Min. Site Area (R-10) | 10,000 sq. ft. | 10,000 sq. ft. |
| Min. Site Area (R-8) | 8,000 sq. ft. | 8,000 sq. ft. |
| Min. Site Area (R-6) | 6,000 sq. ft. | 6,000 sq. ft. |
| Min. Site Area (R-5) | 5,000 sq. ft. | 6,000 sq. ft. |
| Max. Building GFA | 4,800 sq. ft. | 7,500 sq. ft. |
| Max. Height | 35 feet | 35 feet |
[Section 10.4.4]
Specific Use Standards
Arlington County mandates that all duplexes and townhouses meet certain design and placement criteria.
- Separation: No more than one main residential building is permitted on a single lot in R districts, except in townhouse developments [§12.3.10].
- Access: In the R-10T district, semidetached dwellings shall not compromise more than one-third of the total dwelling units in a project [§5.4.4].
- EHO Entrances: For EHO duplexes and multi-family units, at least one exterior entrance must face a street or open onto a front porch that faces a street [§10.4.6.D.1].
Sections Cited
- §5.1.2 Residential (R) Districts Principal Use Table
- §5.1.3 Residential (R) Districts Transitional Use Table
- §5.4.3 R-10T Density and Dimensional Standards
- §5.4.4 R-10T District Use Standards
- §5.9.3 R2-7 Density and Dimensional Standards
- §6.1.2 Multiple-family (RA) Districts Principal Use Table
- §7.1.2 Commercial/Mixed Use (C) Districts Principal Use Table
- §7.18.1 C-TH Purpose
- §10.4.2 Expanded Housing Option Applicability
- §10.4.4 Expanded Housing Option Density and Dimensional Standards
- §10.4.6 Expanded Housing Option Site Development Standards
- §12.3.10 One-family Detached Dwellings
- §18.2 General Terms Defined