The Federal Aviation Administration is still looking for space for a new regional headquarters, a year after setting off a scramble among owners of potentially suitable properties in South King County.

Renton has been home to the federal agency’s regional headquarters for about 20 years, on Lind Avenue at Southwest 16th Street. Keeping the FAA in Renton became a top priority of the City of Renton’s economic-development team a year ago.

The FAA employs about 1,600 workers in Renton.

Now, however, the FAA has told the General Services Administration, which is responsible for finding a suitable building site, that it’s going to need less space than originally thought.

In March 2010 the FAA indicated it would need about 518,000 square feet for a new headquarters. Ten properties were identified in Renton that could accommodate a building that size.

However, for the last several months, the FAA has worked with the GSA to revise its requirements. That building size “likely will be going down,” said Ross Buffington a GSA spokesman in Auburn.

He declined to give specifics on size, nor did he have a timetable for when a decision might be made.

He did say the GSA anticipates it will get revised requirements and will proceed with its procurement and lease process.

Alex Pietsch, administrator of the City of Renton Department of Community and Economic Development, said the city hasn’t heard anything official from the federal agencies. The city has heard the FAA is considering a change in its requirements, he said.

Last spring, he indicated there was no existing building big enough to accommodate FAA’s needs for about 500,000 square feet of space.

The city is pleased to have the FAA in Renton, with its 1,600 jobs, he said.

“We think Renton is the best location for a new headquarters to be built,” he said.

The GSA and FAA have not commented publicly on what sites were on a list of potential sites.. However, last spring sites were suggested in Kent, Seatac, Tukwila and Des Moines, besides Renton.