Depends on when it was built as building regs have massively changed over the years.
I've got the same, a drive sloping to the garage and a Cattle grid type drain in front of the garage door. That was going to a soak away but previous owner then ran a drill through is, pushed a pipe through and that drains straight into the sewer.
I'd definitely get a camera down it to check where it's going and if its roots in the pipes regardless of soak or sewer.
Rgds
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