It is hard to know without specific numbers.
Social Security income isn't taxed by South Carolina.
Pensions are taxed by the state, but there is a deduction of $3,000 if you are younger than 65 and $10,000 if you are older than 65.
For more information, click on the Retirees and Seniors section of this link:
https://dor.sc.gov/tax/individual-income/faq
There is also general exemption on income of seniors over 65 of $15,000 which covers all types of income.
[edit 4/7/2018 7:15 AM PDT]