I live in southern Minnesota and own my own house. The house was built in 1922, on what used to be a refuse site, and we cannot find any plumbing vents. All pipes are visible from the basement. The main pipe goes straight down under our toilet, while the bathroom sink and tub both branch in right below it. Our kitchen sink has its own pipe that goes straight down into the basement floor. When we drain the tub, the toilet bubbles and the kitchen sink barely drains. I've searched the attic, siding, and eventually found a large pipe coming out of the ground along out property line with a cap welded on the end of it. Could this be our vent? Will adding a vent stack help with toilet suction and the bubbling issue? As far as I can tell, most of our plumbing must be under the cement in our basement. There is the big main pipe, going into the cement, and the smaller kitchen pipe going into the cement. There are also 2 floor drains in the basement, one has a block of wood glued into it for some reason. We've has a couple occasions where sewage water will come up from the floor drains, but only when there is excessive rain or when they drained the water tower. Any advice is appreciated.

Do your kitchen and lavatory traps look like this?(see image) Let me know, Tom

Correct

Your home has "S" traps throughout. No vents. Back in Wisconsin we had lots of homes that werm't vented. That's how we plumbed them back then. If any drain runs slow oe is cliged ypu must5 remove the bend of the trap and snake the drain from there. Good luck, Tom

Thanks a lot!