P-trap, S-trap disagreement.

The verdict would depend on your AHJ. The picture represents an approved drain-line configuration (assuming the pipes are sized appropriately) based on earlier versions of the IRC.

This has never been approved by the UPC as far as I am aware.

I had to comment to the client, the plumber was the final say. He was the one who installed it, and explained to her how the venting was setup. So him and the AHJ, were the experts (AHJ can bee assumed ok by passing rough in inspections,etc.). I could only comment about it’s shape, and classic s-trap problems(poor venting, and smells).

So thx everyone,

tom