Lets say like the illustration image, in a pipe running under the 1st floor and along in a basement wall to the main stack and septic tank. How would one detect leaks pre-lawn without demolition. A complete concrete house.

Inherited this mess and wondering if it would be possible to install a tee pipe clean out to join the 2 pipes without breaking out the chisels. Thoughts?.

If you're going to say "call a plumber" then please, spare your fingers the energy to scroll away from this one. Love.

Particularly the main stack through clear out on a branch line outside the house

EDIT: 5/8" (16mm/0.62inches)*

Not sure what the clog is but my money is on a clothes item. Access through clear out on pvc branch line that connects to main stack (where the clog is, somewhere close to septic tank, about 20 feet away).

3 unit complex; my unit (1st/ground floor), unit above me, unit beside me.

My kitchen sink is clogged. When unit above me runs their shower, water comes out my kitchen sink drain.

I did a test where I sealed my kitchen sink drain and let tons of water run in their shower for a good 20 mins. I figured if the water come out my sink, it'd go back out the shower drain... but nope! That didn't happen. All the water kept on draining smoothly.

Something that's interesting is when the water comes out my drain, its grayish and there is - what appears to be - soil sediment when either I scoop the water out or it eventually goes back down the drain by itself, which it does, slowly. And its soapy, which I thought of course it would be since they're taking a shower, but it seems like it's laundry soap, which I drain a lot of on that particular sink.

I tried a snake but it's either not able to grab or break through the clogging obstacle, or not making it at some bend. I did try many times in different ways; fast turning, inching, pulsating... like at least 15 times. It's a no go at the same exact spot all the time. It is a [good] cheap auger though, so maybe I should get a better one, but before I do, I need to know first...

 

Wtf is going on?

 

Appreciate your expertise in this folks! What am I missing?