1957 ranch-style house with basement. Original house plumbing is 3" main stack serving 2 upstairs bathrooms, and 2" second stack serving kitchen, as well as basement utility sink and floor drains. Sewer is public under street.

Around early 1960s previous owners partially furnished basement, and I believe basement bathroom was added at this time. That bathroom was functional until I removed it 2 years ago - was in horrible condition. I plugged the pipes after removing the fixtures, etc, but it was toilet, sink, and shower.

Anyway this week I started installing a interior perimeter drain & sump pump system to deal with water issues and of course I decided I'd start digging near the old bathroom, so I can pull out the old pipes and clean it all up when I re-cement the floor. This is what I've found and I'm trying to figure out how to continue.

Overview of the scene: (Street sewer is in the direction of the wall there with the water main entrance, main stack at left, old basement bathroom lav and vent pipes were located in the verticle line where the block wall was cut out at right)


Basement shower drain at bottom, then toilet drain, then lav towards top:


3" metal toilet pipe slopes down into some sort of squarish cement "box". 4" ring on top of cement box, with 1.5" metal pipe stuck into it. This 1.5" pipe then runs down and connects under shower drain using sanitary T. This T then heads down into the dirt even further - I haven't made it that far yet! Also, in front of and below cement box, is another buried cement structure. This structure has a 1" metal pipe coming off the top of it, then hooking to the side and turning down into the dirt further. What could this be??


View back towards 3" main stack:


My line diagram and questions:


Thanks so much for your assistance and any opinions on this. Should I call a professional immediately? I just intended to remove the unused pipes and cap things off, but I wasn't expecting to find cement boxes and strange pipes under here.



Edited 1 times.

Looks like an old septic tank.

No septic tanks here, in the city on city sewer.

Had a plumber come by and have a look, he just shook his head and said the whole scene looks like an amateur plumbing job. He thinks for the concrete, that someone just encased the pipes in cement before burying them for some reason. No opinion on the tiny pipe, nor the vent into the shower drain above the trap.

Anyway I've decided just to cap everything off and re-bury the whole mess, and hope for the best!

It's just not worth my time right now trying to figure it out.

Packy u got no ideas man?

No big deal, I'm planning on capping the old stuff off and burying it all.

Punt it until something collapses, then hire a real plumber to excavate everything and tie into my new pvc stack, perhaps run pvc all the way out to street.