Basement Toilet / Sewer Connection Thoughts?

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by magikmn, Apr 4, 2013.

  1. magikmn

    magikmn New Member

    Hi All,

    I wanted to post out there to get some of your thoughts and ideas on something peculiar that I haven't figure out. Last year I purchased a 1950's colonial house, with public water and sewer. The 4" sewer main is in the basement and runs about at eye level (~5 ft off the the floor) when you're in the basement, and then shoots out through the basement wall toward the street.

    The odd thing is that there's a basement toilet, a utility sink and washer drain - all 3 drain directly into individual drain lines that pop up out of the basement floor. (The toilet just sits directly on the concrete slab). There is no macerator, pump, etc., so this obviously drains via gravity to SOMEWHERE.... It drains pretty well and I haven't had any issues. From the looks of the toilet, it appears this has been here at least since the 1970's.

    Obviously, there is a drain line under the basement floor. My question is - Where does it drain to? That utility drain line sits at least 4' under the main sewer drain, so it doesn't make any direct connections in the basement. The house inspector hinted that the house just might have dual sewer connections, but I've never heard of that. My father-in-law suggested that perhaps there's a separate septic tank just for that drain line, but I see no evidence of it in the yard.

    Either way, I haven't gotten a clear cut answer and thought I'd put it out there to see if anyone else has ideas. Any questions, please let me know...

    - Drew
  2. cacher_chick

    cacher_chick Test, Don't Guess!

    Land of Cheese
    I'm not clear from what you have said, but in many places the municipal sewer line can be quite deep. Your lines could be connected together between the house and the street connection.

    Normally when I see a building sewer well above the basement floor, it is because the home has or had a septic tank. I know of many neighborhoods where each home had a private septic system, until the municipal sewer was brought in years later.
  3. magikmn

    magikmn New Member

    Thanks Cacher...

    I didn't describe the situation all that well, but you got the gist. I believe municipal sewer was here from the beginning, but I'll check with some of the neighbors who have been here since the 50's. If - and it's a big IF - it was septic at one point, would it be possible for the upper levels of the house to be on municipal sewer and the basement to still be on septic? I'm just curious if that ever happens.

    Thanks again!
  4. hj

    hj Moderator & Master Plumber Staff Member

    Cave Creek, Arizona
    That would normally indicate that it is a "hybrid" system. The upstairs goes out "overhead" so it will operate during times of "backflow" and your basement connects to the same system, but it has a "backwater valve" to minimize backflow, but would NOT allow the bathroom to be used during a "backed up" situation.
  5. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    New England
    To determine if gravity is a possibility, how high is the house from the street? HJ probably nailed it, but if the lot is flat with no elevation change to the street, depending on how deep the sewer line is there, something may not compute.
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