Arlington Proposes New Detached Accessory Dwelling Rules

  • March 7th 2019

by Nena Perry-Brown

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A rendering of the proposed 5-foot setback.

In late 2017, Arlington County passed rules loosening zoning restrictions around what constitutes an accessory  dwelling unit (ADU), primarily for units within the footprint of a single-family home. Now, the County is revisiting regulations for detached ADUs.

A new report from the county presents the setback options under consideration for detached ADUs, offering the public an opportunity to weigh in on the proposed changes. County staff is recommending the Board adopt the 5-foot setback as the standard for where new detached ADUs should be placed on single-family lots.

Schematic of recommended setback rules in R-5 and R-6 zones. Click to enlarge.

The five-foot setback would make 42 percent of single-family lots in R- zones eligible for detached ADUs, compared to 44 percent of lots under a 1-foot setback requirement or 37 percent of lots under a 10-foot setback requirement. 

Currently, detached ADUs in Arlington can have a maximum height of the shorter of 25 feet or 1.5 stories, a maximum footprint of 560 square feet in R-5 and R-6 zones or 650 square feet in other R- zones, and a maximum size of 35 percent of the combined ground floor area of both the house and the ADU up to 750 square feet.

Schematic of recommended setback rules in most R- zones. Click to enlarge.

Existing accessory buildings on single-family lots can already be converted into ADUs if any construction is solely interior. Under the new recommendations, accessory buildings constructed before the new regs are adopted could be expanded vertically as long as the ADU still adheres to height and setback requirements and maintains the existing footprint.

County staff will host a series of public meetings over the next two months on the proposed plans; the Planning Commission will review the recommendation in May and the County Board is scheduled to vote on the drafted standards on May 18th. The public can comment on the draft through March 15th.

This article originally published at https://dc.urbanturf.com/articles/blog/arlington-county-proposes-new-detached-adu-rules/15097.

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