The Arlington County Board voted 5-0 on July 19 to approve a major site plan amendment that will replace an aging 12‑story office building at 4601 Fairfax Drive with a seven‑story residential building containing 328 units while retaining the existing below‑grade parking garage.

Under the approved plan, the developer will demolish the existing office tower, keep and retrofit the underground garage, and construct an 82‑foot, seven‑story building with 328 residential units and ground-floor retail. The project includes $2 million in cash contributions to the county’s Affordable Housing Investment Fund (AHIF) to earn bonus density, participation in the county’s green-building incentive program (LEED Gold target at the 0.25 FAR tier), a northbound bike lane on North Wakefield Street, upgraded streetscapes on Fairfax Drive, and on- and off-site plantings to mitigate encroachment into the Chesapeake Bay resource protection area.

County planning staff and the applicant described the garage as a key constraint that required several zoning modifications — including parking ratios, compact parking percentage and some drive-aisle dimensions — because the top of the existing garage slab protrudes above grade along Fairfax Drive. Staff said the applicant worked with the county to provide mitigation: suspended soil panels to support tree canopy, a stormwater detention vault and off‑site RPA plantings, and a phosphorus-load reduction commitment required by a Chesapeake Bay exception granted on June 17.

The applicant will also contribute an estimated $2 million toward AHIF; staff estimated that amount could leverage approximately 17 to 18 off‑site affordable units through gap financing. The developer also committed to participate in the Green Building Incentive Program at the 0.25 FAR tier, which staff said will deliver LEED Gold equivalents, energy improvements and EV charging infrastructure.

During the public meeting the Planning Commission and the Transportation and Housing commissions each recommended approval. Planning Commission members noted a sense that, given the site’s circumstances and federal tenants in the building, a five‑year term of validity for the approval was reasonable; staff recommended the standard three‑year term and said administrative changes to conditions happen periodically to reflect updated administrative standards. The board opted to approve the project with the standard site‑plan conditions and a three‑year term of validity.

Board members emphasized that converting underused office stock to housing supports the county’s commercial market resiliency initiative and reduces the county’s office vacancy rate. Vice Chair Matt Ferrante, who moved the motion, noted the conversion will add housing in a transit‑rich location and that staff and the applicant had negotiated mitigation measures. The vote was 5-0.

Next steps for the project include permitting and final civil engineering review before building permits are issued; the applicant said retaining the garage and the uncertainties around federal tenants affect scheduling and financing, and could require future minor site plan amendments if market or lease conditions change.