I just purchased my first home with limited knowledge on many things. At one point my house was outside city limits (using a well and septic) and has since been annexed into the city and brought onto public utilities.
My main sewer stack is odd for me. As everything upstairs is ran into it but instead of the bottom of the stack running all the way through the basement floor, it stops about half way down the wall and exits through the exterior basement wall.
The basement looks to be some sort of hack. First off there is a kitchen and bathroom down there. Both rooms are build on a platform in the basement to raise the room and (my guess) is to run the plumbing under the floor instead of going through the basement floor. It all goes to a one point the exits on the opposite side of the sewer stack exit.
The back side of the house has a dirt road and i doubt there's any sewer there that it is tapping into. The old septic (I believe) has been collapse and it was located where the sewer exit is.
There is a square hole cut out in the back of my garage which has slightly been cemented over. Afraid to open this up and find more disasters but looks to be housing something for the basement sewer system. I don't want to open Pandora's box.
Now for the reason I am explaining this…
Next spring, I will be ripping out the entire basement and starting from scratch. Why would there be 2 sewer lines and are the both ok to use (the back one for the basement and the front for the upper level). Why doesn't the main sewer stack not run through the basement floor? And is it possible that I don't have any drain lines under the basement floor to tap into? I want to add a bathroom down there in the future but could see this being a problem.
Also additional details I forgot to add…
House is a 1 story brick ranch build in 1970. The basement in the front, where the sewer taps into the house, is underground. The back of the basement, where the sewer from the basement taps in, is above ground.
I'm clueless and just needed some insight before I got involved with something way over my head and my budget.
Best Answer
Here's my speculation, based on your description and my experience. It is just a theory. Do not commit any resources based on this without collecting corroborating physical evidence supporting it. A direction to investigate at least.
The main floor plumbing goes out to a septic tank. The pipes were not placed lower because there was no need, it just meant digging deeper outside. No one wants to do that without good reason.
When the city sewer was installed, the basement construction tied into it, but the old plumbing was never redirected, it remained on the septic tank. Not the best scheme and possibly illegal, but I'm not surprised someone did this.
It is highly probable there is nothing below to the basement to tie into. The sewer may not be much lower than the basement drainage exit. Anything placed lower than this will likely need to drain into an ejector pumping chamber.