Building a Laundry Grey Water Seepage Pit - Stage 1: Indoor Plumbing

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by ChakaRaka, Mar 27, 2013.

  1. ChakaRaka

    ChakaRaka New Member

    Messages:
    5
    Location:
    BC, Canada
    Hi,

    Our house is on a septic system so our laundry grey water drains into a seperate Seepage Pit. We recently had our (existing) laundry Seepage Pit back up and start flooding out of the washing machine drain pipe. The laundry room sink also stopped draining. After 2 nasty days with a 50' electric snake as well as 2 chemical treatments recommended by a professional, I have conceded defeat. I was able to snake 46' down the laundry drain before I hit something I could not pass, likely a sharp 90 degree or maybe even collapsed pipe. Based on what the old guy who built the house has told me, I believe that the original Seepage Pit is just completely overwhelmed and unable to drain anymore (based on the small size of it and because it is now 25 years old).

    So I am going to abandon, cut off and cap the old line that goes down under the foundation of the house. I will build a new seepage pit with more viable dimensions, shorter run and less twists and turns. I think I have most of the fundamentals of that well in hand, but what I need some confirmation or pointers on is the in-house plumbing.



    Here is what the original plumbing looks like:

    [​IMG]

    Yes, I am well aware that this is a poster for "what not to do", this photo is just here for background and to provide some "why" context to my redesign. The original pipe was all 1-1/2". There was no proper laundry standpipe, it was just jammed in the upper wye where the cap is currently.



    Now here is what I have designed for the new system:

    [​IMG]

    I retain the 1-1/2" vent stack and partial run from the sink, the rest is 2" until it exits the wall. From some of the research I have done, I have been led to believe that I need to add a vent pipe connection between the high point of my laundry drain (just to the left of the P-trap) and the vent stack. Is this correct? Does the rest of my drawing look correct? I am handy being a mechanic, but I am certainly no plumber.

    My other concern was with plumbing through the foundation wall. Is hydraulic cement the correct thing to use to seal this hole, as I plan to at least either insulate, if not backfill around it? I don't want any water to be able to penetrate the foundation where this hole is. I am open to suggestions but am stuck with what I have here. If anyone can offer some pointers or revisions to what I have come up with, I am all ears. We live in Vernon, BC, Canada so the weather is not drastically cold but where the pipe emerges from the wall, it must be somewhat protected from the cold.

    I guess one last question would be whether I should step up to a 3" or 4" waste pipe from the beginning of the trench to the Seepage Pit. I had 4" in mind, but once again am receptive of any feedback or suggestions.

    Thanks so much everyone.

    :D
    Last edited: Mar 27, 2013
  2. cacher_chick

    cacher_chick Test, Don't Guess!

    Messages:
    3,260
    Location:
    Land of Cheese
    While some places promote dumping grey water into the ground, in other places it is illegal. The first step before considering any such installation should be to call the overseeing municipality to see if it permitted where you live.
  3. Terry

    Terry Administrator Staff Member

    Messages:
    15,298
    Location:
    Bothell, Washington
    The sink and the washer trap need to be vented individually and then revented at 42" above the floor.
    A trap arm needs to grade at a 2% slope until the vent. (1/4" per foot)
    Right now you have the trap arm going down with fittings, making it an ilegal S trap that siphons dry.

    I also doubt that you can run the washer into the ground. We haven't done anything like that in decades.
  4. ChakaRaka

    ChakaRaka New Member

    Messages:
    5
    Location:
    BC, Canada
    I am currently trying to find legislation or guidelines on grey water disposal, unsuccessfully. I am also in a semi-rural area that was not even considered part of the city until recently. So according to you guys, my options are to excavate an unknown (and already heavily burdened) septic field and connect it there or spend $20,000-30,000 to be hooked up to municipal sewer? Neither one are really an option currently or in the near future. Do I have any other options? Are there no "grandfathered" exceptions, I am not doing anything new, just repairing what already existed?

    Terry, could you elaborate on this reventing? From another one of your examples on here I see how a vent must be added to the laundry standpipe up to the vent stack. I however do not know what you mean by reventing as I do not recall seeing this shown in other examples. As for the slope, I can see what you mean there and could make that modification.

    Any wisdom to share on how to reseal PROPERLY after drilling through a foundation wall? The crazy old man that built this house is my g/f's stepdad and is riding my ass constantly to get this fixed. I need to figure something out in a timely manner and get back to my real work so I can actually earn some money. Any help or guidance is greatly appreciated.

    :confused:
  5. cacher_chick

    cacher_chick Test, Don't Guess!

    Messages:
    3,260
    Location:
    Land of Cheese
    What you are doing would be considered new work (not a repair). In most places it would require a permit and inspection or approval.

    If it is legal to dump the grey water there, then the system must be isolated from any of the building's septic drain system. Since there would be no connection to the sewer/septic there would be no need for traps or vents. Again, these requirements vary greatly from one place to another, so it should be confirmed with your municipalities building dept.
  6. ChakaRaka

    ChakaRaka New Member

    Messages:
    5
    Location:
    BC, Canada
    I will check what my local regulations are. Based on your local regulations, what options would you have in a repair like this?

    I was under the impression that traps were required even on grey water systems because they still have harmful gasses from decomposition/bacteria growth? I have tried to follow Terry's guidelines on proper pipe slope and venting requirements and this is my revised drawing:

    [​IMG]

    I hope I am on the right track. The home belongs to my girlfriend and she just bought out her ex-husband and our finances are both stretched beyond the limit right now. So between a stressed out (often in tears) girlfriend and a crazy old man slave-driver, I am not getting much sleep or gainful work done right now. We do respite care with mentally handicapped kids out of our home so we need to do a lot of laundry and right now have been out of commission for almost 2 weeks. Any cost effective solutions are much appreciated.

    Does anyone here have much experience with drilling and running pipe through a foundation wall? I am under the impression that hydraulic concrete is the way to go with resealing the bored hole properly. Is that correct? Does an ABS pipe need to be sleeved also or just sealed in with the correct sealant? Sorry to sound so needy, but I am in way over my experience level and everyone is looking at me (the guy who can usually fix anything) for a miracle solution.

    Thanks for all the help so far.
  7. cwhyu2

    cwhyu2 Consultant

    Messages:
    1,348
    Location:
    Cincinnati OH
    This looks okay,pack oakum where pipe goes through concrete then hydrolic cement.
  8. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,268
    Location:
    New England
    There's a limit on how far the trap arm can go before it is vented...it depends on the diameter of the pipe...without dimensions, it's impossible to tell if yours is to code. It would be better to run the vent up the wall behind the sink, then go over.
  9. Terry

    Terry Administrator Staff Member

    Messages:
    15,298
    Location:
    Bothell, Washington
    Trap arm to vent
    1.5", 42"
    2.0", 60"
  10. ChakaRaka

    ChakaRaka New Member

    Messages:
    5
    Location:
    BC, Canada
    I had never heard of oakum prior to googling it. Where does one acquire such a thing? I have never seen it in a store before.



    The pipe on the sink steps up from 1-1/2" to 2". The run from trap to vent stack T is just shy of 5'. My drawing is dimensioned, I just turned that layer off for clarity because it was a gong-show with all the dimensions on it. I imagine that run it likely too long, but was hoping to avoid demoing the entire laundry room to fix the "old-guy's" make-it-up-as-you-go plumbing. If my newest revision is still incorrect, I must imagine that the "Before" photo made you pro's want to puke...



    I found a local bylaw for my area that briefly mentioned waste disposal and touched on laundry. However I found it confusing and could not conclude what the "bottom line" is on regulations. I know drywells/seepage pits are pretty archaic technology but any other option is just going to be out of reach financially for the foreseeable future. I wrote an email to the local planning department to get a concise answer on what my options are.

    Thanks for all the input.
  11. ChakaRaka

    ChakaRaka New Member

    Messages:
    5
    Location:
    BC, Canada
    So my run may be marginally passable then? Are sink P-Traps available in 2"? If so, I could scrap all the 1-1/2" except the existing vent stack and run 2" from sink drain to the drain pipe and be within your guidelines.
  12. cwhyu2

    cwhyu2 Consultant

    Messages:
    1,348
    Location:
    Cincinnati OH
    oakum

    At a local plumbing supply house.
  13. Gary Swart

    Gary Swart In the Trades

    Messages:
    7,386
    Location:
    Yakima WA
    Given your unfamiliarity with very common plumbing materials and requirements for your project, I would urge you to hire a plumber. I fear you're headed for problems with your inspector.
  14. cacher_chick

    cacher_chick Test, Don't Guess!

    Messages:
    3,260
    Location:
    Land of Cheese
    Our regulations prohibit dumping grey water. This is largely because phosphorus and other chemicals in soaps and detergents make their way from the ground into our lakes. This is a prime contributor to increased algae growth, reduced oxygen levels, fish kills, swimmer's itch, etc.
  15. Tom Sawyer

    Tom Sawyer In the Trades

    Messages:
    3,267
    Location:
    Maine
    I suspected as much. Cesspit s were outlawed decades ago. The only viable option I see is to use the local laundry mat.
  16. Terry

    Terry Administrator Staff Member

    Messages:
    15,298
    Location:
    Bothell, Washington
    Use a 1.5" trap, but start the vent closer to the trap, and run the vent back from there.
    If you need to put the basement waste into the existing plumbing, and you can't do it by gravity, you may need a small pump for sink and washer waste.
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