Water Pressure Loss

11 responses

  1. Phil
    April 22, 2012

    Thanks for all of your great advice. Your passion to educate is easily seen in articles like this.

    Now to the good stuff! I have an older home with 1/2" copper and I have terrible water flow problems. If I turned a faucet on (even on low) while someone was taking a shower, the water flow would decrease dramatically. On the other hand, when I first open a valve, for example an exterior hose, you can feel the "kick". With all of that being said, if the pipe that enters my home is 1/2", will changing the pipes over to 3/4" alleviate my problem or will the bottleneck in the beginning of the system prevent the change from helping me?

    Thanks again for all of your great advice!

    • Tim Carter
      May 23, 2012


      Yes. Read all my columns about sizing water lines. You're about to make another mistake.

      • James
        May 29, 2012

        I have a 3/4" pipe coming into my house from the well, would making my main lines 1" and my secondary lines 3/4", and then down to 1?2" in the walls be a good idea? All line under the house are currently 1/2". I've been told having a larger size under the house than what comes into the house might be a mistake or at least overkill!

      • Tim Carter
        June 6, 2012


        I'm a master plumber. What did you discover when you read the above column? What about all the other water pressure and pipe-sizing columns here at AsktheBuilder.com? Read them.

    • Mike
      November 29, 2016

      sounds to me like a volume problem, that is, there is a constriction in the line and the water cannot get through the constriction fast enough to keep the pressure up. Once the faucet is closed, the pressure equalizes and you get a burst when you open it but it dies off quickly. To test put a pressure gauge on a hose bib and open an interior faucet. Leave it run and check the pressure. If the pressure gauge drops substantially it is a volume problem, look for the constriction (partially closed valve?) The faucet is stealing all of the pressure.

  2. Mark Nale
    December 4, 2012

    Losing water pressure when the shower knob is turned to "hot"---I think my handle is a Delta, it is a single handle that turns on by pulling it straight up. Thank you for any help!

    • Tim Carter
      January 3, 2013

      Mark, your question(s) require lots of typing and I have some questions for you. You should consider investing in a 15-Minute Consult with me. Look at my cart for that. Lot's to discuss. I just do short pithy answers here.

  3. coy crawford
    September 20, 2013

    if I have a 2" water inlet and I want to run 3/4" for 175' with 6, 1/2" drops off this header how do I determine if I can do this and maintain a 2-5 gpm flow. I also want this 2" line to go to fill Vats as fast as I can. How much loss will I get taking six 1/2" taps off this 3/4" header that will all be running at the same time?

  4. Kathy Borowski
    July 26, 2016

    My problem doesn't seem to be pressure. I suddenly have no water at all coming into the house. What could this be about and could it all be related to pressure. This is a 50-plus year old house built by my parents.

  5. Dwight H Havens
    September 17, 2016

    The size of the water meter on amunicipal system can also substantially limit how much water is delivered to the house and at what pressure.

  6. David Honan
    October 2, 2016

    The units for cross section area should be square inches. Sorry, nit-picking is one of my few pleasures.

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