We had a farm road rebuilt including install of a plastic culvert. It's double lined and a month after install we noticed a crack on the inside, which is growing. Its on the upper side and water is coming in. Iv'e been in touch with the installer and they are telling me it is not an issue (structural or otherwise) and does not need to be replaced. They are well respected company loved by the community and I trust them, but I cant help but think that a growing crack is an issue or will become an issue down the road. What do you all think? Thanks for feedback, Iv'e searched for this issue here and don't see any similar posts.