I am under contract for a duplex-down condo in Chicago. The building has 6 units, built in 1998. I found that this unit has had sewer problems in 2019 and 2020. In 2019, roots had gotten in, clogged the sewer, and there was water damage. In 2020, some genius dumped baby wipes, clogged the sewer, and there was water damage. Looking at the repairs done in 2019 and 2020, it seems extensive (taking down the dry walls etc). The sellers shared the video of sewer scope from 2020. The video mentions "clay pipe" and "root at joints". However, they have been doing rodding regularly. I am wondering if there is a more fundamental problem here — having to do with clay pipes and lack of hydro-jetting. But I don't have a good understanding of this. Any help is really appreciated. Thanks in advance!