Upstairs bathroom doesn't drain, downstairs is fine.

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The Plumbing Wizard
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Bothell, Washington
Strange call yesterday. All I got on the phone was the upstairs toilet wasn't flushing well and they needed it unclogged. So grabbing my closet auger I headed over. I had previously installed a Cadet 3 for them in that bathroom upstairs, a nice home from the 40's on Lake Washington. Yep, they're right, toilet not working so well at draining the bowl. I use my closet auger on it, flush a few times and it's not looking good. then I see water coming from the tub. She's like, yep, it does that too.
That would have been good to know ahead of time. Mainline backup and in need of a drain cleaner with a snake with cutters, which I don't own.
They let me know that I must be wrong. The downstairs is draining fine, so it must just be local to the toilet and tub. I ask them to check the downstairs again, because if it's a main line, and it's all the way to the second floor, it could be a disaster below. But no, like they knew already, the downstairs is fine.

A little background here. Back in the day, many homes were on septic in the Seattle area.
In the 60's they started laying more sewer lines to clean up Lake Washington. At that time a lot of plumbing in homes was redirected outside the homes. My father was on the Metro planning council during that time when those decisions were being made. His kids were swimming in the lake, living three blocks away and he knew we needed to clean things up.

Anyway, so I mention to the homeowner that there must be two ways out for the plumbing. One for upstairs and one for down. It must be connected in two places. The homeowner let me know that though I was a plumber, even he could figure out that I was wrong. We started looking in the downstairs bathroom where they already knew about a cleanout near the floor. Yes, there's a cleanout near the floor, and about three feet above that one was a second cleanout.


Looking through the shutoff access door is the combo for the upstairs plumbing, with cleanout in the wall three feet high and going through the wall outside. Looking outside through the window we see the 4" sewer pipe above the ground going under the side walk. Yep, there's the upstairs plumbing, with it's own exit out the home.


Just so you know, this is not a common situation, but it can happen. One home, two or more exits on the plumbing. In this case, the upper plumbing, likely roots in the main line leading away from the home. Maybe a little Rootx in their future.


In the Trades
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Years ago in Thousand Oaks, CA. I ran across something like this the bathrooms had one line running out to the street
the Kitchen & Laundry had it's own main that ran out and wye into the first line in the yard so you had to install a main line C/O outside on that line to clear roots


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In this case, the upper plumbing, likely roots in the main line leading away from the home. Maybe a little Rootx in their future.
Any chance that clogged line is still hooked to the septic?
Hey, wait a minute.

This is awkward, but...

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