septic tank anatomy question

Katey · #1 04/20/10, 04:45 PM

So, I seem to have a clog where the main drain line hits the septic tank. Probing from the house side, I feel mush. Snaking from a cleanout, with the snake inside a piece of 3/4 inch conduit to contain it within the 4" line, I pull out some hair (mine) and some fine roots (somebody else's- there are no trees within 40 feet, though). However I seem to have pulled out everything I can grab.

I've also tried flushing twice to raise the water level in the drain line and then opening the cleanout to let the goop flow out backwards, in the hopes that enough would come out to loosen up the clog. I repeated this about eight times, to the point where I'm getting clear water running back. No dice.

I poured a couple of buckets of water directly into the septic tank to confirm my diagnosis, figuring that if the clog wasn't at the intake, water would flow back to the cleanout. It didn't.

Here's where I need help: Probing down inside the septic tank with the shovel, it feels like there is a baffle box at the intake. Does that box open at the top or the bottom? (I'm hoping bottom... top would have to get clogged right away, assuming that solids sink.) I have more conduit and a bender... I could make a custom-bent tool that I could stick up into the bottom of the baffle box from the top opening of the septic tank. I could even run the snake through it. Is this a good idea, or is there something in there I could damage?

The house is circa 1957, and I have no reason to think that the septic system isn't original. It was pumped (and the drain field tested) two years ago when we bought the house, and has gotten part-time use from two septic-savvy people since then. The guy who pumped it guessed that it was a 700 gallon tank, and with my shovel I can't even feel the solid level toward the bottom.

**Cabin Fever** · #2 04/20/10, 06:01 PM

The inlet baffle should be open at both the top and the bottom. Sometimes the baffle is a simple PVC tee fitting and other times it is an open box made of concrete or steel.

Most modern tanks have an inspection pipe (PVC) directly above the inlet baffle (as well as above the outlet baffle). Also, many newer tanks have manhole covers above both the inlet and outlet baffles.

Katey · #3 04/20/10, 07:52 PM

Thanks! I've never had that side of the tank uncovered, but there is an inspection port over the outlet baffle, so I'm hopeful that there is one on the inlet too. I'll let you know tomorrow.

francismilker · #4 04/20/10, 08:46 PM

I'm with cabin fever. Try exposing the top of the tank and look for a small round liftout cover that will let you rod the inlet pipe. Sounds like you could have a grease/hair clog in the inlet that's not letting anything flow either direction in the tank.

tamsam · #5 04/21/10, 12:38 AM

Sounds like you may have the same problem we had several years ago before we bought our house. The tank settled enough that it broke the inlet pipe off where it goes into the tank.We had it pumped and the guy that pumped it told us what the problem was as it didn't need pumped. Wasn't hard to fix just a little messy. We just dug out at the inlet back far enough to be able to cut the inlet pipe off in order to slide a larger pipe over the end. Slide a larger pipe on both ends and one the same size as the inlet inside the two end pieces. You need to be able to slide one of the replacement pipes buk on the inlet far enough ti allow them to act like a sleeve. Once you get that done pour cement in to cover that section to seal it. I hope if this is your problem I haven't confused you to much. Good luck getting it fixed. Sam

Katey · #6 04/21/10, 05:39 PM

Fixed, I think (hope)! There was an access port over the intake baffle.The clog was in the line itself, just outside the tank. I was able to clear it by bending a custom tool out of 3/4" EMT to get around the corner.

I tested it by running every faucet in the house, and repeatedly flushing the toilet, for 20 minutes. There was good flow visible in the tank. Now I'm waiting for the hot water heater to recharge so I can take a well-deserved shower.

I think I will dig up that drain line and do something to ensure that no roots get in there ever again. I'm already digging up the grass in that area for a perennial garden, and I'll be sure to select shallow-rooted plants only for over the line. Maybe Oriental lilies, since it's right outside the bedroom window and they smell delicious at night.

How's that for a happy ending?

gone-a-milkin · #7 04/21/10, 09:16 PM

Yay! I love a happy ending!

The lilies sound like a wonderful idea.
I hope you enjoyed your well deserved shower.