One out of every 10 jobs in selected federal agencies -- perhaps as many as 16,000 here -- will disappear over the next two years, according to President Reagan's blueprint for trimming the nondefense side of the bureaucracy.

Reagan says he will cut 75,000 federal jobs (not necessarily people) between now and the end of 1984. Those cuts will be targeted to avoid the government's three biggest enterprises -- the Pentagon, the U.S. Postal Service and most of the Veterans Administration. Other shelters from the coming RIF (reduction in force) winds will be all or parts of the FBI, Immigration and Naturalization Service, Secret Service, Customs Bureau, IRS and the State Department.

Departments and agencies left to bear the brunt of the 75,000-job cut now have just over 700,000 workers. If you are in one of those agencies, and also belong to a 10-member car pool, think about it.

Defense, with nearly 85,000 workers, is the biggest employer in metropolitan Washington. It will sit out the RIF storms. Departments where the cuts will be centered include Education and Energy, Commerce, Housing and Urban Development, Agriculture, Labor and Transportation, plus big independent agency operations here like the Office of Personnel Management, regulatory agencies and many boards and commissions that are due to shrink, or shrivel up and die.

The Reagan administration --perhaps in an attempt to throw calming oil on Washington's troubled bureaucratic waters -- says the job cuts will be 6.5 percent governmentwide. But the cuts won't be governmentwide. They will be more like 12 percent in agencies where the chopping actually takes place.

To get an idea of what that could mean -- up to 16,000 jobs over two years -- think about the heartache and confusion that the recent round of RIFs (involving about 2,500 people here) created.

Office of Personnel Management officials feel that most of the people hit by job reductions can be put into other agencies -- like Defense -- and that attrition will take care of many of the cuts. Uncle Sam loses 200,000 people a year through death, retirement or resignation. But the right number of people rarely are attrited when and where they are supposed to. So it is likely that agencies will have to rif people.

OPM chief Donald Devine said in a Friday news conference that he hoped Defense and other agencies that will continue to hire can take on many workers cut by other agencies. But while that works out well on paper in computer projections, it often falls flat in practice. Many personnel officials are reluctant to take people who have been riffed by other agencies, and the ongoing government effort aimed at finding other federal jobs for people being riffed has not been as successful as other government programs, like putting a man on the moon.

Solid numbers on the job cuts won't even begin to take shape until agencies get new personnel ceilings and translate them into future RIFs. But the reductions will be bigger than anything metropolitan Washington has seen in a long, long time.