Water line sizing

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by HBM, Jun 11, 2019.

  1. HBM

    HBM New Member

    Joined:
    Jun 11, 2019
    Location:
    Virginia
    I just had a 5 bed/bathroom two story plus basement home built and have a question about my water line size. Originally they installed a 1 inch poly line which was damaged.....after the fact I realized they replaced it with a 3/4 in line (and of course my builder/excavator both assured me it was fine) PSI at the main is around 120. Distance from the main to meter is 35 feet and distance to the house from the meter is 150 feet (house is downhill about 10 feet in elevation). 2 feet after entering the home it converts to a 1 inch regulating valve with 1 inch pex trunks for about 10 feet In the basement ceiling which then goes to 3/4 inch another 30 feet in each direction. I have the prv set at 70 psi in the basement.

    I notice pressure issues mainly if 3 showers are running at the same time or 3 hose bibs are running sprinkers. (This doesnt happen much but my wife has mentioned pressure fluctuations while showering).

    One or two showers at a time are fine which is why I dont think it would be worth digging my yard up at this point.

    Is there anything I can so inside the house to improve this problem? Extend the trunk lines to 1 inch? Extend 1 inch lines all the way to the water heater?
     
  2. Sylvan

    Sylvan Still learning

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    plumbing- - fire suppression
    Location:
    New York
    Your have volume issues for sure. Hopefully you have anti scald type shower body's
     
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  4. Terry

    Terry Administrator Staff Member

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    Aug 17, 2004
    Occupation:
    Plumber
    Location:
    Bothell, Washington
    [​IMG]

    Your home is about 43 fixture units.
    I normally would have used a 1-1/2" poly or PVC line for that amount of volume needed and the the distance. PEX would be 1-1/2".

    Maybe adding a good sized expansion tank would help at this point.

    Just an example. My parents place was 250 feet from the meter to the house. The irrigation system I installed wouldn't work with the original 3/4" from the street meter. By changing the line to 1.5" PVC, the irrigation system worked fine. The heads that wouldn't pop up were now spraying a good amount of water in each zone. Same meter, different sizing on the line.

    3/4" would be too small for a one bath home and you have five?
     
    Last edited: Jun 12, 2019 at 4:34 PM
  5. Reach4

    Reach4 Well-Known Member

    Joined:
    Sep 25, 2013
    Location:
    IL
    If you had pressure gauges before and after the PRV, that could be useful in seeing where the pressure drop is occurring.

    A bigger PRV could be called for. A bigger service line could be called for.
     
  6. HBM

    HBM New Member

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    Jun 11, 2019
    Location:
    Virginia
    I can adjust the prv to get a psi up to 90-100ish. It is a 1 inch zurn 1-600xl

    Where would the expansion tank go? After the prv, before the water softner? Any link to them?

    Thank you guys for the reply
     
  7. fullysprinklered

    fullysprinklered In the Trades

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    self-employed plumber-electrician doing residentia
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    Georgia
    Use two PRVs, one for each direction at the split.
     
    Reach4 likes this.
  8. HBM

    HBM New Member

    Joined:
    Jun 11, 2019
    Location:
    Virginia
    Fullysprinklered,

    Sounds like a good idea to maximize the 120 psi from the main. Do you think doing the split to hot and cold would be better for all the showers?
     
  9. HBM

    HBM New Member

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    Jun 11, 2019
    Location:
    Virginia
    Also I'm not sure my water softner would handle 120 psi which may pose a problem
     
  10. Terry

    Terry Administrator Staff Member

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    Occupation:
    Plumber
    Location:
    Bothell, Washington
    Most codes only allow up to 80 PSI.
     
  11. Reach4

    Reach4 Well-Known Member

    Joined:
    Sep 25, 2013
    Location:
    IL
    Maybe have a regulator (PRV) for the softener, another for all other indoor use, and no regulator for the outdoors. If you do any plumbing changes add provisions for pressure gauges to know what is going on. A boiler drain valve is useful for water sampling and for mounting a GHT pressure gauge.

    I am not a pro.
     
  12. jadziedzic

    jadziedzic Member

    Joined:
    Aug 4, 2006
    Location:
    New Hampshire
    Was the incoming water line downsized with your permission? (No.) Since the answer is no, perhaps it is time to have a talk with the builder and have them fix their "mistake". If they're reluctant to do so a chat with your local Authority Having Jurisdiction might help, given the replacement is not sized properly.

    This mistake will likely nag you the entire time you spend in your new house.
     
    OLD TIMER likes this.
  13. OLD TIMER

    OLD TIMER Member

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    May 18, 2019
    Location:
    FLORIDA
    Yea, that's what I would do.
     
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