Main Drain Problems

[Denise Tate]

I have a 4″ drain running about 300 feet from my house to the cesspool. The property formerly had motel cabins (4 or 5) also using the system – these were torn down by a previous owner. The drain has been clogged with gravel several times. Parts are clay pipe, parts are ASTM 2729 PVC (the thin stuff), repairs while I’ve owned it (one year) were made with schedule 40 PVC – including two new vents/cleanouts). I paid a septic company over $2,000 to fix it the first time (they were out there a few times before diagnosing it as a collapsed pipe, and digging it up to replace a piece). Having less money as time went on, I rented a backhoe for the second clog and did it myself. For the third (latest) clog I used a shovel to expose the pipe, and the thin PVC wasn’t broken but some gravel and large metal washers had accumulated there.

Questions: Am I right in assuming that no snake could clear gravel from a plastic pipe? Is the thin-walled PVC unsuitable for a main drain? Should I replace the whole line with 4″ schedule 40? Also, before I dig up the whole line, I found a 4″ vent, possibly from an old trap for a motel cabin, which is tarry, black and a larger in outside diameter than schedule 40, but smaller than clay: I think its orangeburg pipe. a cast iron floor drain fitting was inserted into it, and it was buried. I was looking for a cap to fit it, but no cap or adapter fit. Any recommendations on how to seal the vent?

[Retired plbg1Participant]

gO TO http://WWW.FERCO.COM AND LOOK AT THERE RUBBER COUPLINGS FOR ONE THAT GOES ORANGEBURG TO PVC AND PUT ACAP ON IT. FOR AS THAT GRAVEL GOES THEY MIGHT HAVE HAD A SEPTIC TANK AND BACKFILLED IT WITH GRAVEL AND DID NOT PLUG PIPE. hAVE A CO. RUN A CAMERA DOWN THE PIOPE AND YOU WILL FIND OUT A LOT BEFORE YOU DIG. lET ME KNOW.

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Art retired plbg

[AKPlumberParticipant]

I would’nt try using a cable (snake) machine to clear gravel and rocks from a pipe. Damage to the cable can result, and all you’ll really do is just push the rocks a little farther down the line, not exactly a “cure”. This applies to plastic OR metal pipe.

Sometimes jetters can blow the rocks down enough to make them exit the main line, but if on a septic system this can cause major headaches as well.

PVC can certainly be used as drain line but I prefer iron or black ABS. If it’s possible, I think replacing the line with SCh. 40 4″ is a great idea. It sounds like this line is so bad that a replacement is warranted unless you enjoy digging it up continuously. Retired’s advice about running a cam down the line is excellent, that will show you where you have to dig and EXACTLY where if used with a transponder. That way, maybe you can get away with just replacing the sections that are really bad or have “bellies” in them instead of ripping up the whole run. His advice on “rubber couplings”, or No-Hub Bands, is also the way to go.

[SometimesRightParticipant]

I measured the orangeburg vent and its outside diameter was about 4.75 inches. The Fernco connector that might fit is listed for use with asbestos cement fiber or ductile iron pipe, and is not stocked by local suppliers. It turns out that a cap for black plastic corrugated drainage pipe was a good fit, but likely not water-tight, so I’ll cover it with a few inches of concrete. I’ll complete the replacement of the last clogged section (I found the clog with an “electric eel”) with schedule 40 PVC, add another cleanout there, and hope it doesn’t clog again. Thanks for the advice – if it clogs again I’ll proceed with your recommendations.

[AKPlumberParticipant]

The new clean-outs plus regular (maybe every 6 months) maintenance snaking/jetting should keep you going.

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