The technology, defense and other government contracting firms that make up the county's economic engine continue to expand their payrolls, drawing more employees to the area.
"Where are we going to put these people?" asked Board of Supervisors Chairman Gerald E. Connolly (D).
He also noted that the densities permitted so far in the county are well below those in neighboring Arlington County and other portions of the region's more urban core. "We're not moving anytime soon to real urban densities," he said.
Still, the trend toward denser building is clear, and it has long been building momentum.
In 1994, the county approved the Tysons Corner Urban Center plan, which sought to transform the sprawling "Edge City" into a more conventional downtown by permitting more building and encouraging sidewalks and other pedestrian amenities.
In January 2001, the county approved a new zoning category that would allow significantly bigger and taller apartment buildings in parts of the county. The old limit constrained projects to 40 dwelling units per acre, enough in some cases for a 10-story building; with the new category, new projects called for as many 120 dwelling units per acre.
More recently, the county moved toward doubling and tripling the amount of building permitted around stops on the proposed Silver Line of Metro, which would run through Tysons Corner to Dulles International Airport and beyond.
Developers are watching closely.
"I think there is a lot of opportunity around Metro stations," said Stan Settle, who heads Pulte Homes's land-acquisition efforts in the region. He would not be specific, citing the competitive nature of the search.
Take, for example, the changes envisioned around the Metro station at Wiehle Avenue on the proposed Silver Line extension.
Once a funding agreement for the rail extension project has been reached, the amount of building on some nearby properties more than doubles. It would be a significant change, though even with the increase, the plans still permit only a fraction of the amount of construction allowed around Arlington's transit stops.
"By increasing the density around the rail stations, we create a pedestrian-friendly community where people will be able to live, work and play and reduce car trips," said Supervisor Catherine M. Hudgins (D-Hunter Mill). "Envisioning the development around the Wiehle transit station, we intend to complement the design that has been a statement for Reston."
Joe Caravella, who lives about 300 yards from that proposed Metro stop, said he is concerned about the possibilities.
He said he dislikes, for example, some of the apartments built near the Vienna Metro stop, across Interstate 66 from the Fairlee project.
"Those apartments at Nutley Street look like a bunch of chicken coops," he said. "I wouldn't even want to walk my dog there. If they plant buildings on every square inch of land, then we have a problem."
He said he is open to more homes if they are "compatible with what we have here."
Aside from the sheer density of the Fairlee project, its approval by the county is also notable because it came despite passionate neighborhood protest.
In recent years, the Board of Supervisors has more frequently bowed to neighborhood pressure, which tended to mean less density, not more.
At Fairlee, as in the past, board members again sought neighborhood consensus. A neighborhood work group was appointed, it met several times and it approved the concept 6 to 3.
Still, dozens of neighbors turned out at county hearings to protest the project. In the end, county leaders said they sought to address their concerns while sticking to smart growth concepts.
"It was painful and difficult," Connolly said. "Obviously, I would have preferred to have more harmony and consensus in the surrounding neighborhoods. But as we look to the future, we have no other choice."