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Drain problem

We had a sewer backup here in a 4 inch line. Putting a camera down revealed some deposits on the bottom of the pipe, which may be solidified grease. We got the pipe draining with the snake, but the deposits remained. Before we try to hydro jet it, would it be beneficial to try putting some lye down with hot water every few days to soften the “fatberg”?
Would cast iron react badly with lye?
When the camera exited the building into 6 inch clay tile, there can be seena number of fine roots in the joints. Has anyone had experience with chemicals (copper sulphate?) for that?—NBC


    JUGHNE Member Posts: 11,075
    Don't know about the CI and lye. Maybe some septic tank treatment would cut the grease.

    I had a 3 bd rental with the 6" clay tile, impervious to everything except tree roots. Mine had a joint every 30-36 inches, sealed with what looked like 1937 tar. During a remodel I was able to push about 35' of 3" Sch 40 PVC thru it and just connect to that inside.
    That was about 1/2 way to the main and eventually finished with 4". But that 35' saved the driveway and a nice tree.
    The copper sulphate works on the roots but it needs to linger in the pipe, preferably overnight. Never ending battle though.

    Have seen someone push 4" thru the 6", my joints were too uneven for that.
  • Jamie Hall
    Jamie Hall Member Posts: 23,428
    The lye won't hurt the cast iron -- nor the clay. However, you would be best off with one of the jelled drain cleaners -- there are a number of brands -- which will tend to stick to the grease deposits. It will take several treatments to get rid of them -- they are astonishingly stubborn.

    The roots are another problem, however. Copper sulphate will get rid of the ones that are there now, and won't hurt the tree -- much. It won't help the tree, either, though, so if it is a valued tree maybe not. In any event, you will need to repeat the treatment from time to time. If you can get a PVC or polyethylene pipe through there, as @JUGHNE suggested, that's a better bet. You may find yourself defeated by a misaligned or broken joint, though.

    What does all this drain to? The drain cleaners won't actually hurt a septic system (won't help it much either), but the copper sulphate may set it back a bit. They usually recover pretty fast, though.

    And for the future -- be careful about getting grease down the drains. I won't say don't ever pour a little grease down the drain, because you can't help it. But if you do, make sure that you use plenty of soap (dish detergent) at the same time, and as hot water as you can get. Larger amounts of grease are much better handled by pouring them, while hot, into a handy left over can which can go out with the garbage. On a bigger building -- say an apartment house -- or certainly a commercial establishment, it's an excellent idea to have a grease trap, properly sized -- and then maintain it.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England