The state health department plans to test water in as many as 30 additional wells for uranium after earlier inspections found high levels of the metal.
Health and Environmental Control Department officials notified about 500 residents of the inspections at a meeting Tuesday.
State epidemiologist Robert Marino said the radioactive element can cause kidney damage, but not cancer, and he told residents any uranium in a person's body would go away after they stopped drinking the water.
Earlier this month, uranium levels more than 50 times those considered safe were found in three wells, prompting the department to gather water samples from 46 wells in the Simpsonville area, in northwestern South Carolina. The 30 additional wells are in the same area.
Tests found uranium levels as high as nine times above the safety standard. Experts believe the contamination is the result of a vein of naturally occurring uranium.
Health officials have said they received no reports of anyone suffering ill effects from drinking the water.