Buried PVC in Chicago

I live in Chicago. I am replacing an existing Backwater valve in my basement and have discovered that under the floor, there is a length of PVC (about 8 feet) connecting my drains to the backwater valve. The backwater valve then connects directly to a clay pipe leading out of the house. From what I understand, buried PVC is against code in Chicago. I realize this is a bit of a subjective question, but is this something I should have fixed?

Additionally, since buried PVC is against code, does that imply that a PVC backwater valve is also against code?

Thanks in advance

I can't speak for Chicago code, but PVC should not be exposed to sunlight. Underground sprinkler systems are all PVC and are all buried. Perhaps there are some pros that can be more definitive that I. Sewer Rats and HJ come to mind, but there likely are others.

One problem with backwater valves in Chicago, such as yours, is that the clay tile is almost always compromised so it will leak like a sieve during a backup, and create tremendous pressure under the floor. I CAN completely demolish your basement floor under the right conditions.