Need Plumbing layout advice

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by StevenW1969, Sep 26, 2013.

  1. StevenW1969

    StevenW1969 New Member

    Apr 29, 2013
    Product Design Engineer
    North Muskegon, MI
    I have a renovation project that I have been working on and have to replace the sewer main pipe and all the interior plumbing. I got the main sewer pipe run it has a 1/2" drop per foot to the septic tank and have tried to keep this same drop throughout the rest of the drains. I attached some photo's of what I have so far. I know I will need a vent pipe for each drain since they will be more than 7-8 feet away from each other. I will use the same size vent as what the drain is so I don't get the gurgling sound when using one of them.

    The advice I need is the junction where the sewer main comes into the home. I currently have a Ø4" 4 way and it just seems like this is wrong that the fitting I need should direct the flow of the waste towards the main line and not just to the main pipe as shown. I haven't glued anything together yet I wanted to test fit everything before I commit my components.

    Any advice would be greatly appreciated.

    Plumbing (1) (960x1280).jpg

    Plumbing (2) (960x1280).jpg

    Plumbing (3) (1280x960).jpg

    Plumbing (4) (960x1280).jpg

    Plumbing (5) (1280x960).jpg
    Last edited by a moderator: Sep 26, 2013
  2. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Sep 2, 2004
    Retired Systems engineer for defense industry.
    New England
    That cross is not the right fitting for that location. Also, there is NO need to make your vent lines that big! Air moves much more freely than the liquid waste. Plus, gurgling may actually be an indication of a well-draining line. If it's very quiet, it may not be flowing well.

    WRT the long at any section has at least 1/4" per foot drop, it CAN vary as long as there are no flat spots, bellies, or rises in the pipe run...IOW, it must be a down slope the entire way.
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  4. nukeman

    nukeman Nuclear Engineer

    Nov 20, 2009
    Nuclear Engineer
    I'm not a plumber, but it looks like you have a few problems.

    1. that cross is not going to fly. things need to be directed with the flow. you may need a double wye, double combo, etc.

    2. You better check on whether you can use that SDR pipe inside. Most plumbers here don't like it even outside. Around here, it wouldn't pass code for under the building (but would be okay from the building to the street). SDR may be okay in your area as I recall another user (also from MI, I think) that was using SDR for a toilet. It was asked where he would even find a flange for that, but he was able to get one locally. In most areas, you would do everything in Sch. 40 (when working w/ plastic). Personally, I would use Sch. 40.

    3. Is that line coming down along the wall a vent or a drain?

    You should also post a diagram on how you plan to tie everything together. Distances, clean outs, fitting type, venting, etc. are all important.
  5. Reach4

    Reach4 Well-Known Member

    Sep 25, 2013
    How deep should his line to the septic tank be below ground? I don't think he needed so much slope.
  6. Terry

    Terry Administrator Staff Member

    Aug 17, 2004
    Bothell, Washington
    Here is a nice link to Bert Polk's plumbing tips

    First off, that four way fitting needs to go.

    All horizontal change of direction needs to be a wye fitting.

    Going from vertical to horizontal needs to be a "long" turn 90, or a wye fitting. The Medium 90 at the far end needs to be changed.


    If this is meant to be a toilet with vent at the wall, :(
    You would be better off using a wye fitting on the horizonal on the downhill side of the toilet for the vent, and then bringing the vent up to the wall.
    A vent is better off at a 45 then being run horizonl below grade.

    I don't think you have the correct pipe either.
    Last edited: Sep 26, 2013
  7. Gary Swart

    Gary Swart In the Trades

    Sep 1, 2004
    Yakima WA
    Dry fitting PVC doesn't work. PVC joints need solvent applied when the joint is made so the pipe will bottom out in the fitting. Dry fit will not bottom out so when properly assembled, there will be a lose of spacing. Also, dry fit PVC can be very difficult to disassemble.
  8. Tom Sawyer

    Tom Sawyer In the Trades

    Nov 29, 2010
    Everything everyone else has said plus I doubt like hell that that blue SDR is going to fly. I know that I would not accept it.
  9. StevenW1969

    StevenW1969 New Member

    Apr 29, 2013
    Product Design Engineer
    North Muskegon, MI

    Thanks Terry For the "Bert Polk's Plumbing Tips" what a huge help that is. I see where I went wrong. I decided to study this pdf for a few days and it has opened my eyes to a lot of misconceptions I had. Since then I took all my purchased fittings back to the hardware and got a refund. I will draw up how I want each drain to be. I have laid out a floor plan of how the new bathroom will look when we are done.

    click here to see the floor plan

    I read our local code and spoke with a few plumbers and they told me that the green pipe is allowed but they said they would not recommend it for sewer, they also said that is used more for drain fields or directing water from landscaping or rain gutter water. Definitely not used for sewer even tho it is allowed.

    I have decided to go with Schedule 40 for the whole project, I realize it will cost more but knowing that the system is solid is definitely worth it.

    I was also wondering what is allowed for being under the slab as far as p-traps , gravel, insulation.

    -p-Traps: I take it I should be using a solvent type not threaded type for under cement slab.
    -Gravel: makes me wonder if it should be under the pipes will it vibrate a hole in it after a while or am I safe?
    -Insulation: I seen Mike Holmes on TV put pink Styrofoam insulation just under the cement and just above gravel is this necessary?

    I want to put a clean out just outside the house on the main sewer line, maybe a double so I can go both ways if need be. Does this sound alright?

    The bathroom floor plan and toilet location changed since I posted this originally. After reading your and others advice & much discussion with my spouse we decided it best to take the time and plan what we need instead of throwing it together on the fly.

    Thanks guys for all your help and feel free to give anymore advice it is greatly appreciated. I do however need to get this finished before snow fly's and it is only a couple months away.

    Last edited by a moderator: Oct 1, 2013
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