We have a pvc pipe running in the block wall of our basement. Inside the pipe, we ran the actual plumbing line to run water downstairs. The pipes are 18 inches underground. Water comes in to the basement through the two pipes. We have tried foam insulation in between the two pipes with roofing cement-did hold up. Have tried several sylcone caulkings-did work either. Does anyone have a suggestion of what type of sealant will work underground to seal the opening between the two pipes?

Try Polyurethane caulk.