Confounded by clog

[JonMatterhorn]

I'm having an issue with a clog, and just can't wrap my head around what the issue could be. My kitchen sink on my upper floor has given me trouble for quite a while. I had a 25 foot pipe snake that I could use with a drill, and stuck it in the vent pipe from the roof, and that seemed to help a couple of times, but later that stopped helping, so I got a 50 foot larger pipe snake. I have tried different drain cleaners including the toughest acid stuff you can get as well as the pipe snake, and it is still 99.9% clogged. I can stick a water hose in the sink drain, block around it, and the water will fill up until it comes spilling out of the roof vent.
What I find difficult to understand is that no other drains are clogged in the house, and I can insert the entire 50 foot pipe snake down from the vent pipe on the roof and yet the water still will not drain. I cannot imagine that the pipe doesn't intersect with any other drains for 50 feet. Is that possible, that the clog could be more than 50 feet down the pipe, but still above the intersection with any other drain lines? I figure the distance from the end of the vent pipe on the roof to the bottom of the basement floor would be maybe 20-22 feet at the most.

Any thoughts/suggestions are greatly appreciated!

 

[Reach4]

I figure the distance from the end of the vent pipe on the roof to the bottom of the basement floor would be maybe 20-22 feet at the most.

Can you identify and access that vertical drain pipe in the basement?

 

[Sponsor]

 

[JonMatterhorn]

Can you identify and access that vertical drain pipe in the basement?

I'd have to cut open the wall or something, I guess it must make a turn somewhere.

Edit: actually, yeah, now that I look (I am working on my shower in the basement and have it ripped out currently) I can see what must be the pipe that turns horizontal in between the upper floor and basement and then runs horizontal out to the end of the house, so I suppose it could actually go more than 50 feet total before joining with any other drains.

 

[Reach4]

I can see what must be the pipe that turns horizontal in between the upper floor and basement and then runs horizontal out to the end of the house, so I suppose it could actually go more than 50 feet total before joining with any other drains.

There is a reasonable chance that the clog is where the vertical turns horizontal. That should have been a long sweep.

Putting in a cleanout there would make sense while you have access.