sewer drainage

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    • #278514
      MasterPlumbers
      Keymaster

      My home os 60+ years old. I understand that back then,sewer lines where not vented. What was the alternative design back then. I have a slow drainage problem in my basement that I beleive is related to some connections in the floor that tie the exit lines togethor prior to reaching the main line. I can’t snake it through and what to avoid digging the floor up to find out.

    • #298666
      Guest

      Sir venting has been around since the first INDOOR plumbing home was built early 1800’s..The main sewer pipe normally doesn’t have a vent per say what the main line does do is vent through a main building vent (4″) that passes through the roof.

      With in four feet of the building house trap you should see a fresh Air inlet (FAI) located about 6″ above grade minim with a cover plate attached with lots of little holes. This FAI should be about 3″ in dia or half the size of your building trap (if applicable) Which ever is larger. Over the years someone may have inadvertently covered your clean out plugs (sewer caps) with a new floor this is a very common problem.

      One of the easiest ways to find your main trap if you have one is to locate your main water supply inlet If your on city sewers and City water. If your on a septic system or well water all bets are off.

      The reason that most sewer traps are located next to the main water supply is MONEY. It is a lot cheaper to dig one trench for several lines (gas, water and sewer) than a separate trench for each. Have a plumber snake your line from the nearest toilet as most codes advise a 3″ opening OR More for this line? Once the toilet is removed and the snake is going through this large diameter pipe IF it gets hung up in the trap you can actually hear it spinning around and this can pin point where they should chop open the floor.

      If you do not have a toilet on the same level it still will work BUT you can also use a floor drain provided your code does not stipulate 1- A separate line for storm drainage and
      2- That the snake will pass through the floor drain trap as most codes EVERY the very early ones wanted all fixtures/floor draining trapped and vented BUT a floor drain can be considered “vented” in some codes as far away as 10 feet from the vent line proper. Call a professional and if needed Video these system with a locator system.

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