Nobody knows for sure how many people in the Washington metro area work for the federal government. The official figure is 354.684. But that does not include the D.C. Government, nor the CIA, nor the National Security Agency, which could add another 100,000. And it does not include the 50,000 to 60,000 military personnel who are stationed here because this is where the Pentagon is.

Whatever the actual U.S. employment level, there are a lot of people who think it should be less. Rep. Jim Leach (R-Iowa) is one of them.

The difference between Leach and most other people is that he is a member of the House Post Office-Civil Service Committee. That committee recently adopted a Leach proposal mandating a serious study of the future decentralization of the government. That means from here to somewhere else.

Leach isn't the first to feel that Washington, which some cruel types refer to as Disneyland East, is out of touch with the rest of the nation. President Martin Van Buren said much the same thing. So did Abraham Lincoln. And others.

During the 1950s, there was a discussion in Congress as to the merits of moving the Capitol Building and all within it to Mammoth Cave, Ky. Another member suggested this whole town be transported to the Rocky Mountains where it would be safer from Russian bombs. It didn't happen.

Now there is a move afoot in Congress including the Senate and House Armed Service Committees, to move more of the government's operations to the grass roots.

In recent years Defense has moved installations and employes from the Washington area to Mississippi, Louisiana and Indiana. Other agencies have shifted some functions to Colorado, Pennsylvania and, uh, Georgia.

Many members of Congress want a piece of Washington's recession proof economy pie for their own home town. The monthly civilian federal payroll here exceeds $600 million. The average civilian federal salary here is more than $21,000.

Others, and Leach says he is one of them, believe the decision-making process of government ought to be out where the taxpayers are. "The arrogance of the bureaucracy, the irresponsibility of the Congress and the insulation of the White House are directly related to the fact that Washington, D.C., lacks a main street."

Leach, Rep. Morris K. Udall (D-Ariz.) and others see no reason why every agency-except the Tennessee Valley Authority, Panama Canal Company and Bonneville Power Administration - should be based here.

The dispersal study, now part of the civil service reform bill being worked up by the House, would identify agencies that could be moved from Washington.

Local merchants, civil servants with roots in Washington and people who write federal columns for newspapers might not like the idea very much, but it is an idea whose time may have come. Leach hopes so.

If the civil service reform bill passes with the Leach amendment, the prospect of decentralization could become a real thing about this time next year.