Falls Church Planning Commission weighs wide-ranging changes to accessory dwelling rules

Falls Church City Planning Commission members spent the bulk of their Wednesday meeting on a work session about proposed changes to the zoning code to allow and regulate accessory dwelling units, or ADUs, across R1A, R1B and RM districts.

The proposal under discussion would add a code definition for ADUs that focuses on use as a habitation and on minimum fixtures ("including at least 1 bathroom and 1 kitchen"), introduce rules to permit detached ADUs, and set multiple dimensional options for detached units: a 5-foot setback with a 20-foot midline height or a 10-foot setback with a 25-foot midline height. Staff also proposed a 1,000-square-foot cap for detached ADUs, a maximum occupancy of three persons for those units, and an intent that special-use-permit reviews for ADUs go to the Board of Zoning Appeals (BZA/VZA) rather than the full Planning Commission.

Project planner Jack Trainor walked commissioners through the draft code and supporting analyses, describing the new definition, the occupancy recommendation and a "bulk plane" analysis that compares proposed ADU height/setback pairs with existing rules for principal structures. Trainor said staff found about 1,500 existing accessory structures in the city’s R1A and R1B districts; the average footprint was 248 square feet and the smallest 75% were under 326 square feet — sizes generally too small to be a dwelling without significant alteration.

"We've provided an amended…