(If you receive SSI, those benefits cannot be garnished under any circumstance.) How much can actually be garnished depends on what you owe for. If you owe back taxes to the IRS, 15 percent of your Social Security benefits can be taken each month until the debt is paid in full. The government uses the Federal Payment Levy Program to garnish your payments. If you owe money on a student loan -- it doesn't matter how long ago you were in school -- the first $750 of your monthly benefits is off-limits to garnishment. After that, the government can shave off up to 15 percent.