Costs of preparing and processing the giant federal payroll will be nearly double normal levels this month. Government attorneys already are bracing for expensive, time-consuming lawsuits as a result of inequities created by the congressional budget snafu.

As often is the case, the problems were caused by Congress. As always is the case, the taxpayers will get the bill.

More than half a dozen major federal-military payroll changes have taken place. Some will stick. Some may be repealed. Some have yet to be sorted out. For instance:

The bulk of the government's white-collar work force and the military will get a 7 percent increase. President Carter originally set the amount at 5.5 percent. His pay advisers said it would be 10.2 percent. They compromised on 7 percent.

Civil servants in the two lowest grades -- grades 1 and 2 -- will get larger raises, about 9.2 percent, than their colleagues because they make the least money.

Civil servants in the three highest grades -- Grades 16, 17 and 18 -- will get smaller raises, about 5.5 percent, than their colleagues because they make the most money.

Those same top executives benefitted -- temporarily -- from a 12.9 percent raise for part of this month. They probably will have to be paid the higher rate for part of that time. The same holds true for members of Congress who are working to whittle back their embarrassing 12.9 percent raise to 5.5 percent which, considering their recent track record, still seems very generous.

Federal Judges, like members of Congress and top government executives, came due for a 12.9 percent raise this month. Unlike their political and bureaucratic counterparts, however, the judge have it in writing -- the U.S. Constitution -- that nobody can cut their pay. Once the 12.9 percent increase went into effect for them, the judges got it for keeps. The Senate and House will try to cut back the judges to 5.5 percent (so that judges won't make more than members of Congress). They may be able to do it in Congress. But once it goes to court the judges stand a very good chance of winning the full 12.9 percent for themselves.

Several hundred thousand federal employes went payless last week, or got only half checks because of the Senate-House budget war games. In addition to the hardships it caused many, the SNAFU will cost more. Government agencies had or will have to run two payrolls, write two checks and either mail or deliver double the number of normal checks to make employes whole.

Capitol Hill workers are eligible for the 7 percent raise (except for top-paid staffers who can only get a maximum of 5.5 percent). But it will be up to their bosses, either individual members of chairmen (chairwomen) of committees and subcommittees, to set pay raise amounts for hill aides.

Employes of federal unions will, in some cases, get the same raises as regular civil servants.

Employes in the top (senior) levels of Grade 15 are caught in a salary crunch because people below them get 7 percent, and those above them get only 5.5 percent. Federal officials are trying to figure out a system that will allow them to move up salary-wise as high as possible without getting more than their bosses.

A lot of Senators and Congressmen voted against the 5.5 percent pay raise. Said they didn't want it. (Since the Senate has kept the wide open door for itself on outside income, Senators probably need the dough less than their House colleagues.)

Despite pay raise disclaimers, one suspects that those members who yelled loudest against the pay raise will be first in line to cash their new higher checks. There is a way they can save themselves the horror of a pay boost. Some members already do it: They can turn back whatever portion of their pay check they feel unworthy of to the Treasury. We will make a spot check n a few months to see how many members who voted against the pay raise have refused it.