GBA Logo horizontal Facebook LinkedIn Email Pinterest Twitter Instagram YouTube Icon Navigation Search Icon Main Search Icon Video Play Icon Plus Icon Minus Icon Picture icon Hamburger Icon Close Icon Sorted

Community and Q&A

Sizing Pipe From Well to House

user-4885540 | Posted in General Questions on

Last year our well installer completed the installation of our well and used one inch pipe from the pump to the pitless and the pitless has a one inch threaded fitting.

I’m finally getting around to running the permanent line from the well to house of around 440 feet. Is there any point in going to a larger pipe than one inch? I was thinking 1 1/4 or 1 1/2 schedule 80 PVC originally.

GBA Prime

Join the leading community of building science experts

Become a GBA Prime member and get instant access to the latest developments in green building, research, and reports from the field.

Replies

  1. Jon_R | | #1

    What is the flow rate (in GPM)?

  2. Trevor_Lambert | | #2

    For a typical flow of 6gpm, the pressure loss along 440' of 1" pipe is about 5.5 psi (assumes straight pipe). I suspect that is fine, but if you look up the specs of the pump you should be able to see what the max pressure it can deliver is. If your flow rate is going to be higher, the pressure drop goes up exponentially.
    http://www.druckverlust.de/Online-Rechner/dp.php

  3. jackofalltrades777 | | #3

    Larger pipe is better for longer runs. I ran 1.25" poly pipe on an 80' run. On a 450' run like yours, I would do 1.50" but 1.25" might suffice. Also depends if the run is going uphill or downhill.

    I am NOT a fan of buried rigid PVC pipe for water well supply line as it can crack and leak in underground applications. I ran 1.25 flexible poly pipe inside a 3" PVC conduit pipe to protect it and it gives it some R-Value protection since it's thermally disconnected from the surrounding soil. Went 24" deep but that depends on where you live. I'm in a Zone 4 climate. Zone 5 and higher might require 48" - 60" for frost protection.

  4. tommay | | #4

    Well, if your pump has a one inch outlet and you are returning to a one inch connection at your pitless, increasing the size of the piping in between will not matter, you may just get more turbulence.
    Q = VA or volume flow rate = velocity x area. So if you change the area of the pipe between the two, the velocity will change accordingly.
    Obviously there will be a slight pressure drop due to friction and head loss, which would be minimal especially if it's only inches. Do you have a separate storage tank, booster pump or pressure tank inside your house? Standard sizing of piping inside your house should be applied according to the number and types of fixtures you have, but one inch should suffice for the volume you need if you have a basic two bath house.

  5. Expert Member
    BILL WICHERS | | #5

    Larger pipe will introduce less back pressure on the pump. This MIGHT make a difference that you notice, but maybe not. The run between the pump and the pressure tank, assuming the pressure switch is AT the pressure tank, and assuming the pressure tank is indoors, will essentially add head to what the pump will "see". As you approach the maximum allowable head, your flow drops off. This means more pump runtime to fill that tank, and more energy use. With the pressure switch located AT the pressure tank INSIDE the house, you still get your target delivery pressure, since the pressure switch will essentially compensate for the pressure drop across that long run of pipe IF the pump can still produce the target pressure with the added head of the long run.

    Assuming a 5 gallon per minute flow rate from your well pump, 1" pipe is going to introduce about 3PSI pressure drop. Going up to 1.25" pipe will only introduce about 0.9PSI pressure drop. This is for HDPE pipe (similar to sprinkler pipe). Personally, I'd use 1.25" pipe on this run unless your pump has a significantly higher flow rate that would justify larger pipe.

    DO NOT use PVC pipe here, even schedule 80. HDPE (high density polyethylene) is a MUCH MUCH better product for this application. You can get the entire run as a single piece of HDPE material, so no splices or couplers that can fail, and its a FAR more durable material. HDPE is what the water utilities now use for new water lines, including big water mains, and is also used by gas companies, power companies, pretty much everyone that is installing underground facilities these days.

    Bill

  6. Trevor_Lambert | | #6

    "With the pressure switch located AT the pressure tank INSIDE the house, you still get your target delivery pressure"
    This is only true until you empty the pressure tank, at which point the pressure delivered is dependent on the pressure the pump is able to deliver at the end of the pipe. This may not happen very often, depending on your draw and the max rate the pump is set up for. If you've got bath tub filling at 9gpm and your pump is set to max out at 6gpm, then you'll empty the pressure tank pretty quickly and the pump will run continuously until the draw stops and the pressure tank is full again. So there are several variables. The pump max will usually be set based on the refill rate of the well. My well only refills at about 2gpm, so the pump is limited to 3gpm.

    1. Expert Member
      BILL WICHERS | | #7

      The pump cut-in and cut-out pressures won’t change with the pipe length since they’re entirely controlled by what the pressure switch “sees” at the far end of the pipe run from the pump. The length of that run makes no difference here, unless it acts to limit the max pressure the pump is able to deliver. What does happen is that the long run slows the rate of flow from the pump, making it take longer for the pressure tank to recharge.

      I suppose in the case of a heavy water flow drawing down the tank at a rate beyond what the pump can deliver, you could see more pressure drop, but that would be the same with a short run of pipe too. Basically the only thing the long run really changes is the flow rate from the pump, the delivery pressure to the house isn’t really affected, as long as the pressure switch is located inside the house.

      Bill

  7. DanaLowe | | #8

    Thanks for the info on sizing pipes from your well to the house.

  8. Deleted | | #9

    Deleted

  9. EricTaylor55 | | #10

    Better late than never, right? When it comes to sizing the pipe from your well to the house, it's essential to consider the flow rate and pressure requirements. While one-inch pipe may work fine, going for a larger size like 1 1/4 or 1 1/2 schedule 80 PVC could offer some benefits. It can potentially improve water flow and reduce pressure drop over a longer distance. Plus, it allows for future expansion or upgrades if needed. I'd recommend consulting with a professional well installer or plumber to get their expert opinion based on your specific needs and well setup. Also if you ever need assistance with waterproofing or related services, https://rooterworx.ca/waterproofing is a reputable company to consider. They specialize in waterproofing solutions and can help keep your home safe and dry.

Log in or create an account to post an answer.

Community

Recent Questions and Replies

  • |
  • |
  • |
  • |