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RM-12 Residential Medium-Density 12 District in Arlington

Jurisdiction: City of ArlingtonCode Version: August 26, 2025

The RM-12 Residential Medium-Density 12 district in the City of Arlington is designed to accommodate a wide range of low- to medium-density housing types with a maximum residential density of 12 units per gross acre. This district permits a variety of residential formats including single-family detached homes, duplexes, and townhouses, and it is the only district where the City of Arlington allows the development of "Cottage Communities" as a Planned Development [Section 2.2.7, Section 5.11.1].

Purpose and General Character

The City of Arlington established the RM-12 district to encourage diverse housing options that meet the needs of various residents. The primary goal of the RM-12 Residential Medium-Density 12 district is to provide a transition zone between lower-density single-family neighborhoods and higher-density multi-family districts [Section 2.2.7].

The character of the RM-12 district is defined by its mix of attached and detached residential structures. While the City of Arlington allows traditional single-family homes in this zone, the standards specifically encourage the development of single-family attached units, duplexes, and townhouse projects [Section 2.2.7]. In all City of Arlington residential districts, complementary uses such as parks, open space, schools, and religious assemblies are also permitted to support the residential environment [Section 2.2.1].

Dimensional Standards

Development within the RM-12 Residential Medium-Density 12 district must adhere to specific lot and building requirements to ensure the medium-density character is maintained throughout the City of Arlington.

Standard Duplex Townhouse Single-Family Non-Residential
Max. Density (units/acre) 12 12 12 N/A
Min. Lot Area (sq. ft.) 6,000 2,900 5,000 15,000
Min. Gross Living Area (sq. ft.) 800 800 1,500 N/A
Min. Lot Width (ft.) 60 20 50 60
Max. Building Height (ft.) 60 75 60 60
Max. Lot Coverage (%) 40 40 40 40

[Section 2.2.7]

Setback Requirements

The City of Arlington mandates specific setbacks for structures in the RM-12 district to ensure adequate light, air, and privacy [Section 2.2.1].

Boundary Type Minimum Setback (ft.)
Arterial or Collector Street 40
Local Street, Alley, or Private Access Easement 20
Interior Side Yard 5
Rear Yard 10
Adjacent to Single-Family (Side or Rear) 20

[Section 2.2.7]

Permitted Land Uses

The RM-12 Residential Medium-Density 12 district allows for several residential and institutional use types. The City of Arlington categorizes these as permitted by-right (P), permitted subject to supplemental standards (P*), or requiring a Specific Use Permit (S) [Section 3.1.2].

Residential Uses

  • Dwelling, duplex: Permitted [Section 3.1.5].
  • Dwelling, single-family detached: Permitted [Section 3.1.5].
  • Dwelling, townhouse: Permitted [Section 3.1.5].
  • Dwelling, live/work: Permitted subject to supplemental standards [Section 3.1.5].
  • Cottage Communities: Permitted only as a Planned Development (PD) [Section 3.1.5].

Group Living and Public Uses

  • Assisted living facility (≤ 6 residents): Permitted [Section 3.1.5].
  • Assisted living facility (≥ 7 residents): Requires a Specific Use Permit [Section 3.1.5].
  • Boarding home facility: Permitted subject to supplemental standards [Section 3.1.5].
  • Public or private school: Permitted subject to supplemental standards [Section 3.1.5].
  • Religious assembly: Permitted [Section 3.1.5].
  • Community garden: Permitted [Section 3.1.5].

Off-Street Parking Requirements

The City of Arlington requires RM-12 Residential Medium-Density 12 developments to provide off-street parking based on the type of dwelling unit or facility.

Use Type Parking Requirement
Duplex 2 per dwelling unit
Townhouse 2 per dwelling unit
Single-Family Detached 2 per dwelling unit
Live/Work 1.5 per dwelling unit (plus area-based retail/office/comm calc)
Assisted Living (≤ 6 residents) 2.0 per dwelling unit (max 1 per bedroom)
Nursing Home 1.0 per 4 beds

[Section 5.4.3]

Sections Cited

  • Section 2.2.1 General Purposes of All Residential Zone Districts
  • Section 2.2.7 Residential Medium-Density | RM-12
  • Section 3.1.2 Explanation of Table Abbreviations
  • Section 3.1.5 Table of Allowed Uses (Residential Districts)
  • Section 5.4.3 Off-Street Parking Standards
  • Section 5.11.1 Cottage Community Design Standards: Purpose and Intent

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