If you co-signed a student loan for your child or grandchildren, better make sure that they continue to be up-to-date on their payments. Otherwise, the U.S. Treasury Department will garnish your Social Security.

Generally, it won’t take the whole check — about 15 percent is average — but who can afford to factor even a small loss of this sort into their retirement planning?

The number of people of retirement age who have student loan debt is increasing. From Jan. 1 through Aug. 8, 115,203 debtors have had at least one Social Security payment garnisheed by Treasury because of a delinquent student loan. That’s a huge increase from 2000 when just six debtors had their Social Security check garnisheed for failure to pay, the Treasury points out.

The government has been able to garnish Social Security checks to pay off student loan debt since 1996. The government also can grab a Social Security Disability Insurance payment for the same reason.

Nearly 5.5 million people between ages 40 and 49 years old and more than 6.3 million people 50 and older have student loan debt, according to the Federal Reserve Bank of New York. People have student loan debt when they are past 62 for a variety of reasons. Treasury will allow a borrower to extend a debt greater than $60,000 for as long as 30 years, so people who went to college in their 30s still may be paying while they are eligible for Social Security. Other people acquired new student loan debt during the Great Recession. But mostly these loans stem from people co-signing college loans for their offspring.

Declaring bankruptcy won’t help. Neither private nor federal student loan debts can be erased by bankruptcy. The Treasury says it gives people with delinquent federal student loans plenty of chances to work out a payment plan, and it doesn’t even start collection procedures until the loan has been past due for two years.

Student loan debt is shaping up to be a presidential campaign issue with both candidates calling for lower interest rates. President Barack Obama supports loan forgiveness, while GOP candidate Mitt Romney opposes it. “Don’t expect the government to forgive the debt you take on,” he told listeners at a town hall meeting in Ohio.

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