Sewer trouble here splits along the same line everything else in Hanahan does — the age of what is in the ground.
Older lines, roots and joints
In the original streets the laterals are clay or early cast iron, and after seventy odd years the joints weep. Roots from the mature trees along those roads find that moisture and grow in, then catch everything passing. Cutting them clears the line for a season; lining removes the joints they are getting in through.
Newer neighborhoods, settling instead
Around Tanner Plantation the pipe is sound PVC. What happens there is the ground settling under a section so it sags and holds water, which then collects waste. That is a repair to one part rather than a whole line.
Flat ground does not help
Hanahan sits low and flat, so sewer lines here run with very little fall to begin with. That means a small sag matters more than it would somewhere with steeper ground, and it is why we look with a camera before quoting rather than guessing.
Ask to see the footage
Roots, a sagging section, a crack and a collapse cost very different amounts to put right. You should be able to see what you are paying to fix.