In the process of finishing off a basement bath that had rough ins installed when we built the house 3 years ago. I was about to install the shower p-trap but when I cut the cap off the 2" stub below the concrete slab, there was some standing sludge/sewage in the pipe. There was no liquid, but it was soft and stinky and about 3/4"deep in a 2" pipe. It had little bugs crawling in it too. Is this normal for something that has been capped off, or is this backflow from the main stack about 5ft away? There shouldn't be anything else draining in this pipe, and I would think the connection at the main stack would prevent any backflow.
Thanks for your thoughts
Thanks for your thoughts