What the plumbing code requires
Illinois sets the floor. Its plumbing code wants a clean-out at least every 50 feet on 4-inch line and at every change of direction sharper than 60 degrees, and it sets a minimum fall for drain pipe so solids keep moving instead of settling. A new nonconductive lateral installed since January 1, 2026 also has to be locatable from the surface, so the next crew to dig in that yard can find it.
Towns add their own. Maryville’s 2026 lateral requirements call for SDR 35 pipe on CA-7 bedding, with the Illinois Department of Public Health inspecting the first five feet from the foundation and the village the rest. Troy charges $4,850 to tap on in town and $100 for the sewer inspection; O’Fallon’s single-family tap fee is $3,000.
Working with the builder and the inspector
We work alongside the homeowner, the general contractor and the town’s inspector, so the line is where the plans say, at the depth the main allows, and ready when the inspector arrives. A badly laid line shows up later as backups, odors, settled pipe, sinkholes in the yard and a failed inspection. With Dig N Drain, the line goes in correctly the first time.
