It can be. https://ttlc.intuit.com/replies/3299920
It depends on how much income you have and filing status. For the 2018 tax year, single filers with a combined income of $25,000 to $34,000 must pay income taxes on up to 50% of their Social Security benefits. If your combined income was more than $34,000, you will pay taxes on up to 85% of your Social Security benefits.