Waste System Questions

Discussion in 'Plumbing Forum, Professional & DIY Advice, Tips & ' started by wetzelja, Sep 2, 2012.

  1. wetzelja

    wetzelja New Member

    Messages:
    9
    Location:
    Michigan
    Hi, I'm trying to figure out how to proceed with a project and hope I can get some feedback. I'm a DIY who learns mostly by reading forums, so I'm not an experienced plumber, though I have replaced supply and drain lines before.

    Here's my long story: I've got a small cottage (800 sq ft) in a rural area that has been added to throughout years and years of updates, and I don't believe it's all up to code. All the plumbing is in a very tight crawlspace under the house. A few years ago, right before I bought the place, the township put in a sewer system. I was told by the previous owner that everything was hooked up to that system and I no longer had to pump out the septic tank. So I hadn't been.

    Recently, my bathroom sink and shower drains began draining slowly. I decided to put a snake down there through a cleanout valve outside the house, and after progressing for a bit, it promptly got stuck. To the point (again, long story) where it would not come out for anything, even attaching a winch to the snake's line (the cable eventually snapped multiple times through multiple attempts). While trying to figure out what to do about getting the cable out, I did some investigation and realized some odd things. It appears that my cottage has two waste systems. The bathroom sink, shower, and laundry lines all tied together in a 1.5" line, went outside and into the ground, and (my guess is) into the old septic tank. The toilet and kitchen sink tied together in a 4" line, and after a bit of redirection, tie into the township's sewer cistern in the back yard.

    The good news, I think, is I can leave the snake cable in the old pipe, and make new connections into the sewer cistern also. My options are to tap into it by digging and extending the 1.5" line that goes out into the yard, then connecting it to the 4" line that goes to the sewer cistern, or connecting the 1.5" line to the 4" line under the crawlspace.

    Here are some of my concerns:
    1) Neither the shower nor the laundry line have p-traps, and none of those 3 fixtures are connected to any vent (possibly why it was draining slow in the first place?). If I just run that combined line and connect it to the cistern out back, I will need to provide venting for them, right? Otherwise the gases will just run right out of the cistern and into the drains, and they'll continue to drain slowly? I don't think I have room to vent each one. Where they all connect and come out of the house before going down to the ground, I wouldn't be able to just put a tee there instead of an elbow, with a stack outside the house, would I? I've read about AAVs. Would I be able to install three of those, one at each fixture, instead? I understand the code varies on those.

    2) When I followed the 4" drain, it goes downhill from the toilet, past the kitchen sink, and then down into the ground. It appears that somewhere near where it turns and goes into the ground, there must be a connection for a vent that comes out of the house. Is that proper venting? Isn't the vent stack supposed to be uphill from the fixtures, not below them? So if I connected the three additional fixtures (bathroom sink, shower, laundry), and they're uphill from that vent also, that wouldn't work, would it?

    Sorry this is so long. I realize that the system could probably use an entire rehaul, but it's a cottage bought extremely cheaply a number of years ago that I'd rather not put much money into. Any feedback or observations would be appreciated.

    Jamie
  2. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,896
    Location:
    New England
    You must install p-traps and vents for things to work and be safe once connected to the town's system. EACH trap needs to be vented, but you don't need separate vents going through the roof - you can combine them in the walls, or the attic (there are rules on where and how to do this). If you're going to be crawling under there to do some work, I'd change that 1.5" line to at least a 2" line. Most places, you need at least a 2" line once it goes underground.
  3. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,488
    Location:
    Cave Creek, Arizona
    1. You should NOT have a "cistern" if you are connected to a city sewer.
    2. The fixtures need traps and vents even if they are NOT connected to the city sewer.
    3. We cannot tell you how to reroute the piping because we are not there to see the situation as it exists.
  4. wetzelja

    wetzelja New Member

    Messages:
    9
    Location:
    Michigan

    Wow, I was under the assumption that this forum was a bit more DIY-friendly. That response seems a bit harsh. I understand you're not physically at the location, isn't that the point of a discussion forum?

    I'm aware that the fixtures need traps and vents, in my post I was asking my options for venting, not how I can get away with not venting.

    And apparently I'm using incorrect terminology by using the word cistern (did I mention I'm not a licensed plumber?) Here's what I meant:

    Plumbing 02.jpg Plumbing 01.jpg
  5. Tom Sawyer

    Tom Sawyer In the Trades

    Messages:
    3,128
    Location:
    Maine
    Where does that pump tank pump too?

    To do it right, you will probably need to open up walls and such to run vents
  6. wetzelja

    wetzelja New Member

    Messages:
    9
    Location:
    Michigan
    This was put in when the township put in the sewer system, so I'm assuming it pumps it to the main waste lines?
  7. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,896
    Location:
    New England
    You would only need that if your house was below the main sewer line, which obviously, it is or they wouldn't have installed one. A cistern is essentially just a big tank for storing stuff (typically water, not sewage).

    There are lots of rules on where and how vents are installed. Some general ones, the distance between the trap and the vent has limits based mostly on the diameter of the pipe - larger pipe, the further you can go to the vent. Once a vent, always a vent (IOW, a vent can't be used as a drain, but above a drain it can become a vent). Vent lines must slope like a drain system, since they can accumulate moisture from the roof penetration (rain, snow) or condensation. There are lots of other rules which include the types of fittings required and their placement and orientation. That's one reason why a plumber is an apprentice for years before he can become a licensed practitioner.

    To adequately help, a good drawing of what's there might be sufficient, but without seeing what's there, it's really hard to tell you what's required to bring things up to code.
  8. wetzelja

    wetzelja New Member

    Messages:
    9
    Location:
    Michigan
    So what's the correct term, is that a lift station?
  9. wetzelja

    wetzelja New Member

    Messages:
    9
    Location:
    Michigan
    All right, here we go... Here are some drawings that hopefully give a better picture. The top flat layer is the floor of the house. The bottom layer is the ground of the crawl space.

    Basically I've got two different waste systems:
    1) the toilet and kitchen sink that go through a 4" line to the middle of the house, vent out to a pipe on the outside of the house, and goes down under ground, toward the back of the house, and connects with the lift station/holding tank before getting pumped to the township sewer system.
    2) the bathroom sink and shower drains that connect up (all via 1.5" line) with the washer line, out the house, down into the ground, and out to the old septic tank (I'm assuming).

    I'd like to connect the second drain system with the first main system. I thought it might be easier to do that by connecting it out in the yard. So I'm asking for feedback on that decision.

    BUT, I recognize that without vents in those three fixtures in the second system, I'm going to have issues. So I'm wondering how to vent those with limited room in the crawlspace and without tearing apart the walls.

    Looking at the red markings:
    1) can I add piping at those locations, tie them together to a line that goes outside right there, and then put a vent stack pipe along the outside wall of the house?
    2) Or, could I put a vent stack pipe where the united connection comes out of the house? Or will that not work because it's downhill of all the fixtures? And, it's one, not three vents?

    Last question, if my only vent on the main system is downhill of the toilet and kitchen sink, is that even doing anything? Doesn't the vent need to be uphill of the fixtures?

    Thanks for any feedback or observations!

    Plumbing1.jpg Plumbing2.jpg Plumbing3.jpg
  10. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,896
    Location:
    New England
    You can tie the existing stuff into the main line, but in most places, anything underground has to be at least 2". From today's viewpoint, the kitchen sink, washing machine, and shower should start out at 2" and probably be bigger once they join up. Having the WM on the same line as the shower and other things at a 1.5" pipe is asking for slow draining and backups.

    EACH trap needs its OWN vent (there are a few exceptions, but since the toilet is already going to the main, I don't think you have one of those situations where you can wet vent anything. Without a vent at each trap, you likely haveteffectively S-traps, which actually empty quite well, in fact, too well, and they siphon themselves dry, if not by themselves, by water running past them from another trap!

    Venting each trap doesn't mean you need that many pipes running up above the roof, but the rules to combine them are fairly specific. They can be combined at 42" above the floor or 6" above the flood plane of the highest fixture whichever is HIGHER. How you connect them, the fittings you use, and the way it is connected is critical to be considered an actual vent.
  11. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,488
    Location:
    Cave Creek, Arizona
    quote; Wow, I was under the assumption that this forum was a bit more DIY-friendly.

    There is a big difference between helping a DIYer to fix a faucet and designing a drainage system. THere can be more to a drainage system than just running a pipe from point A to point B, and we seldom have all the information we need to diagnose it and even if we did, there is no guarantee that what we describe will be what you install.
  12. Gary Swart

    Gary Swart In the Trades

    Messages:
    7,329
    Location:
    Yakima WA
    Another way to put it is that not everything is a DIY job. Sometimes the best DIY advice is to get professional help. I can put a Band-Aid on a small cut, but if it requires stitches, I see a professional.
  13. wetzelja

    wetzelja New Member

    Messages:
    9
    Location:
    Michigan
    All of which I completely understand. Which is why I was asking for feedback from professionals instead of just pretending all I had to do was run a pipe out to the back yard and let everything drain onto the lawn. How would I know if it is a relatively easy job that a DIYer is capable of doing or if I needed to hire a professional unless I ask? So that is what I came here to do! What I was not expecting was to be immediately dismissed. That definitely surprised me, given the popularity of this forum. When I said I expected it to be more DIY-friendly, I guess I expected it to be more friendly.
  14. wetzelja

    wetzelja New Member

    Messages:
    9
    Location:
    Michigan
    So, with the understanding that vents and traps are required, I would appreciate any feedback on one of my earlier questions:

    With this setup, is this even functioning as a vent?
  15. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,896
    Location:
    New England
    To be a vent, it has to go up from the trap. Anything that comes off the drain line after it is below the trap can't be a vent. The whole idea of the vent is that it must be able to move air in the system while waste flows out...if it's below, then the waste could block the vent from operating.
    Last edited: Sep 4, 2012
  16. wetzelja

    wetzelja New Member

    Messages:
    9
    Location:
    Michigan
    Thanks for the reply. So really, neither of the lines are really vented at all. Argh.

    I had gotten a quote from a local plumbing contractor (before coming to this forum) to connect the three latter fixtures to the main line. This information helps me know that I need to make sure that quote includes venting, not just hooking up to the main line.
  17. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,896
    Location:
    New England
    As I said earlier, once a drain, always a drain; or, once a vent, always a vent. You can't mix functions - they are separate and distinct. They must be joined properly, or they don't work properly.
  18. wjcandee

    wjcandee Wise One

    Messages:
    1,820
    Location:
    New York, NY
    Maybe dumb questions wetz, but...

    I understand from reading the pros' (and friendly engineers') comments that it looks like you need some dwv system revisions, particularly re venting and traps.

    But do you know for sure that this line of greywater (interesting to me that that's what it is) is connected to your old septic tank? Michigan is an IPC state, so (okay, reaching the limits of what I should be talking about...) if I understand it can sometimes be used for underground irrigation and toilet flushing. (I also know that, notwithstanding the IPC, in my jurisdiction, "washings" from the human body are considered sewage. which has to go in a public sewer if it is available, so this would still be verboten where I live.) Any chance that your local jurisdiction was somehow *not* interested in collecting it? Any chance that those lines go somewhere else? Have you popped the top of your old septic tank and seen whether anything is running into it? (Or is it not accessible? Where we live we are required to have a lid at ground level that meets certain requirements both for access and for limitations on access.) Dye tab in the shower or whatever?

    Actually, the more I think about this, I know that in the jurisdiction in which lies our family home outside NYC, when the sewer system is expanded and people are connected to it, it is not only customary but in fact legally-required that the old septic tanks be caved in and filled in. Wonder why they didn't (if they didn't) do that at your place?

    I'm thinking that at the end of the day if the local jurisdiction wants it, you are probably already required to be giving it to them. But I'm just intrigued that the greywater is running in a little dinky line off somewhere, maybe; and before you pay to do this work at least you probably want to be sure that it isn't already running into your lift station (or somewhere that it's expected to be running).
    Last edited: Sep 4, 2012
  19. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,896
    Location:
    New England
    Some places used to separate the laundry from the rest of the waste lines...the thought that the lint would clog up the leach field. Course, if you pumped your tank regularly, that shouldn't be an issue. But, a WM pumps a lot of water fast, so who knows. The two could already be joined somewhere underground - it's not a bad idea to verify that. But, most codes want anything underground to be at least 2".
  20. wetzelja

    wetzelja New Member

    Messages:
    9
    Location:
    Michigan
    Thanks for putting thought into this, wjcandee.

    I honestly don't know for sure where the grey water goes from the sink, shower, and laundry. I assumed it was the old septic tank. I know that I ran the water for a long period of time, with the lid of the sewer holding tank in the back yard off, and it never seemed to enter there. My only conclusion was the old septic tank.

    I did float that theory to the township water supervisor, because I wondered if it was an oversight and they'd cover the cost of having it done. While he didn't give me definites because they used third-party contractors, he said it wouldn't be unusual to have two lines and they were only required to connect the main from the toilet.

    I don't actually know the location of the septic tank, so I haven't tried to dig it up. I'm fairly certain that it wasn't caved in because all of this transition was happening as I was purchasing the property, and I didn't see any of that in the yard.

    The whole thing is just a mess. This 1.5" line going out into the yard is bizarre and poorly assembled. When I started digging it up at the point where it comes out of the house, it goes 90 degrees into the ground for about 18" and then goes 90 degrees out to the yard. NONE of these elbows or sections of pipe were cemented together, just dry-fitted.
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