Hi everyone, I've been reading this forum for quite some time, but this is my first post.

I have an overhead sewer project going on in my basement right now and when the plumbing inspector stopped by he said that my old sump pit is not up to code and has to be expanded so that sump basin's inlet is at the drain tile level which is 2' below the basement floor. My sump pit is about 50 years old and it has a clay liner. It is 18x24" in size.

My plumber that is working on the sewer suggested to expand my current sump pit to 24x40 and that way the inlet will be at the drain tile level, as required by the inspector.

I've never heard of a sump pit that deep.
Does anyone know what IL plumbing code says about sump pit sizing and inlet levels? I've searched and couldn't find any sump pit regulations in the code. Can I install a basic 18x24 plastic sump basin and have holes drilled in the bottom so that ground water can get into the basin from below?

I've already spent a fortune on the overhead sewer and want to avoid any additions to the bill as much as possible.