City continues work on accessory dwelling rules; council narrows options ahead of April public hearing

Falls Church City planning staff returned to council on March 24 for a final work session on a draft accessory dwelling unit (ADU) ordinance, seeking direction before a public hearing and final vote on April 14.

Why it matters: The draft ordinance would allow interior, attached and detached ADUs as-of-right in most residential zones, with limits on size, occupancy and height. Council members and staff framed ADUs as a tool to add housing options without large-scale redevelopment, but several members said protections are needed to limit privacy, tree-canopy and rear-yard impacts.

Staff's package and recommendations: Jack Treanor, a planning staff member who led the session, summarized changes since the last council work session: a revised corner-lot setback rule to prevent ADUs on corner lots encroaching on adjacent front yards; a height-and-setback matrix that would allow a 5-foot side-yard setback for single-story ADUs no taller than 15 feet and a 10-foot setback for ADUs up to 20 feet (1.5 stories); a cap on detached ADU size (1,000 square feet) with a staff proposal to allow ADUs up to 60% of the primary dwelling's floor area when the main house is 1,200 square feet or smaller; a 50% maximum coverage of the required rear yard by all accessory buildings (staff recommendation, up from the current 30%); and a maximum of four occupants in an ADU.

Public comment and neighbors: Two neighborhood residents who earlier submitted written comments, Kelly Port and Brian Sperry of Walnut Street, reiterated concerns about corner-lot ADUs and about nonconforming primary dwellings enabling nonconforming ADUs. They asked that ADUs be required to meet the same front-yard setback rules as the primary dwelling, even when the primary dwelling does not conform to current setbacks.

Council debate and open issues: Council members discussed four topics staff flagged for final direction: corner-lot treatment, setback and height, size allowances for ADUs on very small houses, and maximum rear-yard coverage. Positions varied: - Setbacks/height: Staff and the planning commission supported the 5-foot (one-story)/10-foot (1.5-story) framework. Several council members favored an 8-foot compromise for one-story ADUs (10 feet for taller ADUs), citing privacy and tree-rooting space; others favored the staff plan to avoid adding permitting complexity. Some members suggested an owner-initiated waiver or special-use path where neighbors consent, but staff cautioned that such paths add time and cost. - Rear-yard coverage: The planning commission recommended no rear-yard limit; staff recommended raising the current 30% cap to 50%. Several council members expressed concerns that uncapped coverage would allow too much built area in rear yards and suggested a 40% or 50% cap as compromise; council indicated a majority preference for 50% at the work session. - Size for small principal dwellings: Staff proposed allowing an ADU up to 60% of the primary dwelling's gross floor area when the primary dwelling is 1,200 square feet or smaller. Council members asked staff to include a fallback minimum (for example, "whichever is greater: 60% or X square feet") to avoid a situation where houses just over the 1,200 threshold are disadvantaged.

Enforcement and process clarifications: Staff said conversions of existing nonconforming accessory structures would normally require a special-use permit and that enforcement of a short-term rental prohibition would operate primarily by complaint-driven zoning inspections. Staff also provided a draft intake/checklist for permitting ADUs and said building-safety and zoning staff are coordinating processes for handling applications.

Next steps: Council asked staff to tidy the draft ordinance language and graphics, confirm how the zoning administrator and BZA will treat conversions and nonconforming structures, and produce a short-term monitoring/reporting approach so council can review how many ADUs are applied for and built. The public hearing and final consideration are scheduled for April 14.

Ending: Councilmembers said they wanted the final ordinance to permit new ADUs while protecting tree canopy, privacy and neighborhood character; staff will return with a revised draft for the April public hearing.