The “Windfall Elimination Provision” reduces an individual’s own earned Social Security benefits if the worker put in less than 30 years of “substantial” Social Security-covered work, and imposes a phased-in reduction for those with between 20 and 30 years of such work. The “substantial” work threshold is adjusted each year, currently $23,850.
The provision primarily is of interest to those under the CSRS system, who often manage to earn enough credits under Social Security even though Social Security is not part of the basic CSRS system, through military service, or civilian work before, after, and sometimes on the side during, their CSRS careers.
The maximum reduction is about $450 a month, which would come from a Social Security benefit that likely would be relatively low to begin with, since it’s based on relatively small Social Security-covered earnings.
Various proposals have been raised over the years to either abolish the provision entirely or to soften the impact, but they have not advanced far and you should not count on them being in place by the time the penalty would hit you.
See also, Windfall Elimination Provision – WEP and Social Security at ask.FEDweek.com
However, there are exceptions to the penalty even under the current rules. First, the modified formula does not apply to survivors benefits. It also does not apply to you if: you are a federal worker hired after December 31, 1983 into the FERS retirement system; or you were employed on December 31, 1983, by a nonprofit organization that was exempt from Social Security and it became mandatorily covered under Social Security on that date.
Also, the reduction in the Social Security benefit under the modified formula cannot be more than one-half of that part of the pension attributable to earnings not covered by Social Security.