In concrete pits, it is not uncommon to have a core drilled hole with a plumbing connection that is inaccessible. For a tank liner, this means that our standard way of handling outlets cannot be accommodated. No problem though, there are ways to handle these holes.
One method is to extend a pipe stub into the pit. The liner can then be notched to allow the pipe stub to pass through the liner. Then a “boot” is made to go over the pipe stub and is sealed to the liner. You can refer to our video on how to install a pipe boot.
Another method is to make a compression seal around the hole. With the liner installed, a corresponding hole is cut into the liner and the studs of the anchor bolts are passed through the liner. Then a compression ring is placed over the studs and tightened down. This creates a seal of the liner against the concrete wall. The concrete does need to be smooth in this area so that the liner can be sealed to the wall. A high-quality sealant should be also be applied to ensure the liquid seal of the liner at this spot.