Spetic backup

[highpeaksdrifter]

My system is 12 years old. A week ago it backed up in the downstairs toilet for the first time. I had the tank pumped out the next day. A week later I had the system inspected by a professional. He opened and checked the center manhole, the outlet cover and the distribution box. The standing water level was just below the outlets. He used a video snake to examine the system from the house to the distribution box. He said everything is in very good shape and doesn’t know what caused the backup.

Something caused it and I’m worried it will happen again. Does anyone have any suggestions on a possible cause?

Thanks in advance.

[Nestor]

I woulda suspected the main drain line from your house to the septic tank was partially clogged, but you say that that line was video inspected and turned out to be clear. When they did the video survey, you should have been offered the option of having a videotape of the survey made for an extra $10 or so. ALWAYS have a tape made because if you talk to a plumber, and he's convinced it's just GOTTA be a partially clogged main drain line, then you can let him watch the tape and see for himself.

If the main drain line from your house clogs up, it's normally with solids from your kitchen sink. So, the real secret to figuring out what's happening when you have drainage problems is to have a good idea of how your drain piping is connected. That's because the solids from the kitchen sink are going to accumulate in any near horizontal drain piping that the kitchen sink empties into. If it turns out the toilet that backed up is "upstream" of the pipe that carries the waste water from the kitchen sink, and the vent stack in your basement is downstream of it, then running a video camera from the cleanout at the bottom of the vent stack to the septic tank could very well show that this drain pipe is clear. But, if the pipe carrying the water from the kitchen sink is upstream of the pipe you video surveyed, then THAT's the pipe that needs to be cleared, or at least checked with a video camera to see if it's partially clogged.

You see, if this is a basement toilet that backed up, and it was added after the house was built, then it's not likely to be vented. That's because venting that toilet would have required running a big 3 inch pipe through the walls of the house to the roof, and the worst that could happen if the toilet didn't discharge into a vent stack would be that some sewer gas could come up through the bowl if the bowl was empty. So, where I live, the plumbing code doesn't require an added toilet to discharge into a vent stack; you simply have to connect it so that it drains into the same drain pipe it would if it did discharge into the vent stack.


So, if your house has an auxiallary vent stack that carries the solids from the kitchen sink to the main drain line from the house, and the basement toilet got connected to the underground portion of that drain line, then it's possible that drain line is clogged, but the main drain line coming off the bottom of your vent stack all the way to the septic tank is wide open. If the basement toilet was simply connected to the drain line coming off the bottom of that auxially vent stack for the kitchen sink, that would explain why your toilet backs up even though the main drain line is clogged.

Maybe go down into your basement and stand beneath where the kitchen sink is. You should see a drain pipe of some sort near you somewhere. If it enters the concrete floor of your basement, then look around where it enters the basement floor for a "clean out" in the concrete floor. If your basement toilet is anywhere near that clean out or even remotely under your kitchen sink, then you need to run your video camera or snake into that clean out to check that drain pipe.

Alternatively, just test the drain line from your kitchen sink. Simply line the floor around your basement toilet with towels and then run the dishwasher and drain the kitchen sink at the same time as the dishwasher is pumping water out. Have a helper in constant communication on a cell phone ready to put the plug back in the kitchen sink and shut the washer off if you see a great big bubble of air coming up your basement toilet bowl followed by a gush of water that spills over the rim of the bowl.

[LazyPup]

I would agree that the backup was probably caused by an obstruction in the house main drain or the house sewer line from the structure to the septic tank.

Most likely as they pumped the tank the obstruction moved on into the tank and whatever it was, got hauled away in the truck, never to be seen again.

[acrepairteam1985]

Septic systems are the worst.