Metro Washington's 300,000 white collar civil servants would be held to a 4.8 percent raise this October and the area's 100,000 federal-military retirees would have to wait until March 1982 for their next cost-of-living raise under legislation approved yesterday by the Senate Governmental Affairs Committee.

The proposals, part of personnel-related spending cuts ordered by the Budget Committee, now go to the full Senate with the backing of the Reagan administration.

President Carter's final budget called for a 5.5 percent October raise for the nation's million professional, technical and clerical U.S. civil servants. Union leaders say raises between 9 percent and 13 percent are due. Carter also proposed that government retirees who now get COL catchups each March and September be limited to a single annual adjustment.President Reagan wants an even deeper "reform" in the way government salaries are set, leading to a maximum 4.8 percent adjustment this fall. Despite his pre-election promise not to tamper with retirees' twice-yearly COL adjustments, Reagan now favors one raise a year.

If the legislation clears Congress, retired federal, postal and military personnel who are due a minimum 2.5 percent COL adjustment this fall would have to wait until March for their next raise.

By law the Governmental Affairs Committee was bound to come up with spending cuts -- as directed by the Budget Committee -- in programs it controls. Federal pay and retirement make up most of the committee's jurisdiction.

Here is the vote on the COL issue: To keep the March and September raises, Sens. Ted Stevens (R-Alaska), Charles Mathias (R-Md.), Lawton Chiles (D-Fla.), David Pryor (D-Ark.), James Sasser (D-Tenn.) and Carl Levin (D-Mich.).

Voting in favor of one retiree raise per year: Chairman William Roth (R-Del.), Sens. Charles Percy (R-Ill.), John Danforth (R-Mo.), William Cohen (R-Maine), David Durenberger (R-Minn.), Sam Nunn (D-Ga.), Thomas Eagleton (D-Mo.), Mack Mattingly (R-Ga.) and Warren Rudman (R-N.H.).

Dropping one of the COL raises would save nearly $1 billion a year, the size cut ordered by the Budget Committee. The governmental affairs unit also voted to trim another $1 billion by reducing the number of consultants in federal agencies, and cutting back federal travel. That cutback might be used as a tradeoff on the Senate floor, in an attempt to save the twice yearly COL system. But for now all signs point to a raise no higher than 4.8 percent for active duty personnel, and a delay -- until March 1982 -- for the next retiree raise.