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  1. #1
    Join Date
    Jun 2002
    Posts
    460
    Just wondering if there are any plumbers here and what their thoughts are on using a 1" I.D. line on a 3/4" meter vs. a 3/4" line. I'm getting conflicting reports (one plumber says use the 1", builder says he's crazy).

    Anyone know of a good plumbing bulletin board like this one somewhere?

  2. #2
    Join Date
    Sep 2002
    Posts
    3,708
    Its really simple,the 1 inch will get you more volume and less pressure,the 3/4 will do the opposite,but not by
    much.




  3. #3
    Join Date
    May 2001
    Location
    Bennington, Vermont U.S.A.
    Posts
    13,864
    The meter will create a slight pressure drop. If it is a short run of pipe then there probably won't be much of an effect. But if you have a long run then you will diffinately decrease your volume.

  4. #4
    Join Date
    Nov 2001
    Location
    East Texas
    Posts
    931
    I did it on my house I built 1.5 years ago.

    Works great.

    I am close to the water supply,(well).

    My pressure is around 90.

  5. #5
    Join Date
    Jun 2002
    Posts
    460
    Originally posted by simpleman
    Its really simple,the 1 inch will get you more volume and less pressure,the 3/4 will do the opposite,but not by
    much.
    Yes, but when you get to the house, it will step back down to 3/4 anyway.

    What I have heard from at least one source is that what you are trying to do by doing this is to reduce the pressure drop due to friction in the service line itself, which gets worse as the line gets longer (as well has at higher flow rates). So, if you have two otherwise identical plumbing systems where the service line enters the house plumbing system, say 70-80 feet from the meter, the house with the 1" service line would have overall higher pressure and greater volume than the house with a 3/4" in line.

    Since I've been getting conflicting information (even the posts above don't agree), I was just looking for something "official".

  6. #6
    I've installed many service lines. We only use 1" if it is a long run. Under 100' 3/4 is plenty, use type k copper.

  7. #7
    Join Date
    Sep 2002
    Posts
    3,708
    Allright Joe ,i just spoke with my brother master plumber
    for over forty years,he say the 1 inch will give you more volume,then 3/4 at the same pressure.

    And that 3/4 copper is good for 100 feet,after that go
    1 inch.But he claim he no longer does 3/4 no matter if it under 100 ft,because he like the volume that 1 inch gives
    him.

    And he kind of chuckle when I ask about the pressure and
    the size of the pipe,and said all thing being equal between one inch and the 3/4 the pressure will not change only the volume.





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