Main line clogging

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by TN, Mar 29, 2013.

  1. TN

    TN New Member

    Messages:
    5
    Location:
    TN
    First let me state that the issue I'm about to describe has happened twice in the past 3 months.

    We built the house that this issue is happening in a little over nine years ago. About a year ago we started noticing issues with our plumbing, an occasional smell coming from the sink, slow toilet drains, etc. This continued for a few days until we noticed the toilet did not flush, which led to nothing going the drains. Instead of calling a plumber I called the septic tank cleaning service and had them pump the the tank, hoping that was the issue. Once the tank was empty they had me go inside and flush the toilet. Nothing came out and they found a large wad of paper/"junk" right at the bend of the main line that drops into the line. They removed the blockage and everything worked fine for about a year.

    Three months ago we started notice some of the same signs and then the blockage of nothing emptying from main line a few days later. We have two clean outs, one just outside our main bathroom that is within 10 feet of the septic tank, and another at the opposite end of the house, outside the second bathroom. The one beside the main bathroom is inside the garage, so I was told to open the furtherest one (outside) and emptying the line and allowing "simple" usage until someone could come with a hydro jetter. Living in the country does have some advantages.

    Two days later they arrived, jetted the line and stated that they noticed a large amount of paper exit when jetting the line, with no real explanation for the clog other than the possible amount of paper usage.

    Three days my wife got out of the shower, while the washing machine was going, and flushed the toilet to dispose of tissue from blowing her nose. She brought it to my attention that the bowl did not empty so we immediately stopped the washing machine, as it was starting to drain. Upon stopping it we heard the kitchen sink burp and the toilet empty. I flushed the main toilet and it was slow to drain. I then flushed the second toilet and it did not empty. Went back the the other bathroom and noticed water sweeping from the base of the toilet. I opened the same clean out and waited for the same jetting service to come. This time they jetted the clean out in the garage and stated that they really could not state that they were able to observe a strong presence of blockage, due to resistance in the jetting line. Closed the clean out cap, flushed the toilets, ran some water and everything seems to be working fine for now.

    The gentlemen that owes the jetter states that he believes our problem could be due to one of two issues. 1.) a problem with the venting two the main bathroom, causing clogs to happen in the line due to slow drainage. or 2.) we do use the guest bathroom a lot as it is closer to the main living area. He said it could be a possibility that the amount of paper being used, along with the distance and low flow of water being pushed down the line towards the tank could allow the paper to not exit the line and build up over time, eventually causing the blockage. The only time water is used in that bathroom is when something is flushed. No showers or barely any usage happens in the bathroom.

    He suggested that we might want to look into adding a vent to the clean out in the main bathroom and look into getting a high capacity, powerful flush toilet to add in the break down of paper and pushing it down the line.

    I'm looking for suggestions and advice. Any given will be greatly appreciated.
  2. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,348
    Location:
    New England
    Adding a vent (assuming what's there is properly vented in the first place) does not speed up a draining line...so, that's not going to help. Having improper venting (as long as there is at least some) means that the waste will often flow so well that it literally sucks other traps dry as the waste passes by in the main. If I had to guess, I'd guess your main line does not have the proper slope, or has a belly in it. It is fairly common in a drainage system for the waste to only move part of the way to the tank with the first flush. Subsequent water usage will push it further. If there's a bad joint that catches things, over time that may also create a stoppage. Water jetting can clean the inside of the pipe, but it may not always fix something that might be caught in there like maybe a pen, pencil, hairpin, toy, etc., that is catching things. A properly sized snake might be called for. If you can see the drain line from say the basement, check that it doesn't have any dips or bellies and verify the slope (should be at least 1/4" per foot).
  3. TN

    TN New Member

    Messages:
    5
    Location:
    TN
    Thank you for taking the time to respond!

    We are on a slab so seeing the pipes are impossible. Is it possible to still get a "belly" in it since we have a slab? Let's say the slope is off, shouldn't we have noticed this before living in the house for almost 10 years? If the slope is off what are my options?

    To my knowledge nothing has gone done the drain, we have no children and we neither recall losing anything down the drain.
  4. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,348
    Location:
    New England
    Depending one how well the line was initially placed and backfilled, yes, it's certainly possible it may have a belly or the slope is off. Things can settle. All it could take is one pipe end that was not properly reamed, and it has a sharp edge, or not being fully seated in the fitting, and there could be a slight depression or catch point. Since this has happened a couple of times recently, it might be time to get someone to come out with a sewer camera and check the line. If it sees any standing water, that's the symptom of why things are clogging up - somthing's preventing it from flowing...gravity keeps it from going back uphill! Outside, it's possible the pipe could have been collapsed if it was run over by something heavy. Normally doesn't happen if things are at the proper depth. Or, the house foundation could have settled a little, and crushed the top of the pipe.
  5. TN

    TN New Member

    Messages:
    5
    Location:
    TN
    How would one go about fixing the problem if its due to sloping and standing water, especially since we are on a slab?
  6. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    27,296
    Location:
    Cave Creek, Arizona
    The septic cleaners diagnoses are both wrong. A vent does not restrict drainage UNLESS there is also a problem with the sewer line. A "high power" flush only pushes stuff out of the toilet. Once it gets into the pipe it moves along EXACTLY like any other toilet's waste does. Your problem seems to either be with the pipe installation or the paper being used. First you have to find out exactly what the problem is, and where, then you can start thinking about how to cure it.
  7. TN

    TN New Member

    Messages:
    5
    Location:
    TN
    Thank you for your reply, I greatly appreciate it.

    What would cause the installation of the pipe to change after 10 years living here, again we're on a slab.?

    Thinking back to when we had our tank emptied, there was a large clog caught right in the bend of the elbow dropping from the main line down into the tank. What could cause this? Is it possible that soap, etc. has caused a build up in the line in turn resulting in this problem?

    Why do we occasional get a smell from our kitchen sink? Is this the result of the line beginning to clog?
  8. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,348
    Location:
    New England
    As I said, depending on how they prepared the area under the foundation, it could have settled...I've read stories about there being a big gap between the slab and the soil - if the slab is reinforced, it may not crack, but just be hanging there. Jetting a pipe tends to clean it off reasonably well. A snake, properly sized and used, can scour it clean as well. First, you need to determine if there's any standing water in the pipe when it is clean (i.e., no obstructions). If there is, then this will tend to collect crud until it becomes clogged. A drain relies on gravity to allow stuff to flow down it, and any flat or reverse incline areas slow the flow down and often can cause stoppages eventually. The elbow you noted may not be a long sweep one or it may have not been installed properly (i.e., not seated, or worst case, maybe even not glued!), leaving a gap and a clog point. To determine what the state of the line is may require the use of a camera. If they identify a problem, the choices then become either abandoning that line and running a new one, or tearing up enough of the slab to redo the bad section. As to the kitchen sink...if it is not vented properly, the flow from other fixtures may siphon it dry, allowing sewer gasses to escape. Now, it could simply be a buildup of crud above the trap. A trap can only prevent smells from getting through it...if there's a long downpipe or say a cross-over between two sinks, that's a lot of area that could have food waste or other crud accumulate that a trap would have nothing to do with. When the sink smells, try running a cup or two of water slowly and see if that stops it. If it does, that sink is probably not vented. If it doesn't, the down pipe leading to the trap is dirty. If you have a disposer, those can be notorious for smells.
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