I've lived in my home for 3 years, during that time I've found that the previous owners were DIY fanatics that did pretty much everything you can imagine wrong. You should have seen the electrician's face when I called him in after I took down all the walls upstairs. He forbid me to turn on the power until he had cut and capped every line running to the second floor.

Anyway my latest discovery is that the house has two clean outs to the sewer line. One is properly capped thanks to the guys that changed my hot water heater when I moved in (the previous cap involved lots of tape and a metal plate). That clean out is above the basement floor, two feet from it there is a square 2x2 foot hole that has large rocks at the bottom. I just figured it was something to do with rain water overflow, it never overflowed so I left it alone. Then today I took a shower and wham it was overflowing like crazy. I removed all the rocks and found a second clean out cap on the floor of the pit about a foot or two down. I tried to unscrew it but it came free right away. Below that was a round hole in the cement that leads right into my sewer line. It was actually convenient for snaking and I removed the clog (niece's friggin hair piece from easter) and the water quickly drained.

But now I've got a hole slightly smaller than the size of a standard clean out in my basement floor with nothing sealing it other than a cap placed over it and weighed down by rocks. It isn't threaded so I can't attach a cap. I'm worried about gas, and from my limited experience with hydraulic pressure I'm pretty sure the hole is actually making it easier for clogs to form by reducing the pressure in the pipe when it is full.

Has anyone seen something like this? Any suggestions for sealing the hole would be greatly appreciated.. I'm stumped at the moment.

Any chance you can post a picture. This sounds like a true nightmare, great advertising for the home inspector industry though. It really sounds like you need to get 3 plumbers out to give bids on what they say must be done to bring this home to code and a safe level

I had it inspected, sob kept saying things like "well we're not allowed to comment on that due to lawsuits" in my opinion it was a waste of money.

I've actually repaired or had various workmen repair the vast majority of the crazy crap they did. I thought I was about done then this craziness pops up. My camera is dead but I'll post once it takes a charge.