These days, there are many elderly people who depend on social security as a main source of income. For some people, social security benefits are their only form of income. If this is your case, then you will not be required to pay taxes on your social security benefits. Social security benefits that are the only source of income for an individual do not need to be taxed. However, if your modified adjusted gross income exceeds the limit set forth by the IRS, then your social security benefits will be taxed. For a single person, the income amount is set at $25,000.