Modified Home Run Pex Water Distribution System

Discussion in 'Plumbing Forum, Professional & DIY Advice, Tips & ' started by poky1234, Feb 27, 2014.

  1. poky1234

    poky1234 New Member

    Messages:
    27
    Location:
    Woodbridge Ontario
    Hello,

    Iam restoring a century home and I am replacing all the old plumbing system. I am trying to decide between a Home Run System or a Modified Home Run System. The house is 2 story. I want to use the Modified Home Run System and use sub manifolds. If I were to run to the second floor to supply a lav , toilet and tub could I use 1/2 inch pex to supply the sub manifold or would I have to go to 3/4? Town water pressure is around 45 lbs.

    Thanks,

    Doug
  2. wjcandee

    wjcandee Wise One

    Messages:
    1,766
    Location:
    New York, NY
    Why are you focusing on saving 50 cents on the materials?

    Can I get away with half-assing the thing? Probably.

    Will it be as good as if I used the proper materials? Probably not.

    PS As you probably know, this pex stuff moves a lot less water per diameter than pipe like copper. So why not give the house a plumbing system that it can be proud of instead of trying to figure out the minimum that you can get away with?
  3. mikeplummer

    mikeplummer Plumber

    Messages:
    190
    Location:
    Ontario, Canada
    you are in Ontario - so our plumbing code will dictate your minimum pipe size determined by supply fixture units, distance and service pressure. I always run 3/4" to a second story and branch 1/2" off it. I also use copper main runs
  4. Terry

    Terry Administrator Staff Member

    Messages:
    14,763
    Location:
    Bothell, Washington
    The cold for a bathroom should be 3/4"
    You do add a toilet with that.
    Hot can be 1/2"
  5. poky1234

    poky1234 New Member

    Messages:
    27
    Location:
    Woodbridge Ontario
    Thanks for the answer Terry and Mike.
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