We're in a new house with septic. The drains have been working great until yesterday. We had a small wedding here in mid-March, and have had 6-15 adults in the house at a time with no issues. All of the plumbing is in one end, almost a corner of the house, and it drains to a septic system. All of the plumbing is sched 40, and probably max 30 yrs old, maybe newer.
Upstairs bathroom sink and toilet, downstairs bathroom, sink, shower, tub, toilet and kitchen sink. They all clog (well, all of the downstairs stuff, I haven't run enough to clog the upstairs, and I'm not going to try) which makes me think it's in the run to the septic or the septic itself.
Bathroom sink meets shower drain ~1'. That shower that's ~6-7' from a tub. The drain from the shower connects to the drain for the tub in a T, and shortly there after, it takes a right turn, and ~7' over, the downstairs toilet joins the fun which then runs into a 90º elbow down to the main line. The upstairs toilet and sink then join the party, maybe 3' back from the downstairs toilet on the main line. The whole shebang then hits the main pipe to the septic tank. From the opposite side, the kitchen sink hits the main line to the septic at about the same spot as the other drain. The septic tank is ~13' from the wall of the house, so the distance to where all of the drains hit the pipe is probably max 15' from the septic tank. I've got a 25', ¼" snake. I have run the snake out to it's max 2 or 3 times. I don't think I run into what seems like any major obstructions. I just pulled the lid off of the first tank and saw that at least 1' of the snake was protruding from the end of the PVC in the septic tank which was several inches above the top of the "water" in the tank. I was able to grab the end of the snake, and with my wife inside, we were able to easily pull the snake back and forth by at least 1' in a sawing motion.
So if I can get the snake through, and the end of the pipe in the septic system just has a trickle of clear water running into the septic tank, WTF?
top of photo, drain from bathroom sink right to left to shower, left edge of photo, J trap at shower. Back ground shows the drain from the tub where the toilet meets it going left to right, and on the very right edge, you can just see the 90º elbow down to the main line.
This shows where the upstairs bathroom meets the main line to the septic, and then the downstairs bathroom line has the 90º elbow down to the line from the left, and from the right in the background you can see the smaller pipe coming from the kitchen sink which looks like it might be a little low.
The septic line runs from under the house, probably under the AC unit.
I didn't take a pic of the main line in the septic tank when I had the lid off. But this is a reasonable facsimile of what it looked like. It's a PVC pipe out of the top side of the tank, in our case, several inches above the stuff in the tank. The top of the tank closest to the house is a mass of stuff that's full of drain fly larva.
Rough approximation
Thoughts or suggestions?