Gov. Henry McMaster told reporters on Sunday that it will be days until the cresting of rivers in the area of most concern, along the state's border with North Carolina.
Officials have been warning for days that flooding could be disastrous in the Yadkin-Pee Dee River basin, into which several swollen rivers that originate in North Carolina flow.
National Weather Service officials noted that as much as 16 inches (40 centimeters) of rain have fallen in Chesterfield County, with other nearby areas marking similar rainfall totals from Florence.
Transportation Secretary Christy Hall says workers are still working on projects along two roadways to divert rainwater to keep U.S. 378 and U.S. 501 Bypass passable.