I'm planning on DIYing our water tank and water pressure tank but need help on a few things. My plan is to have 2 water inline going into our house main line. First water inline will be direct from water provided. Second will be coming from our water tank which connects to a water pressure tank. However, I want the second line to release water only when water pressure in first inline is low (for ex: 20 psi). Is this possible? What materials do I need to get this to work?

From my understanding, water pressure tank has an always open water outlet so it releases water when a faucet is opened inside the house.

In theory, I can think of using some sort of water control gate valve on the second line and then a water pressure sensor on the first line that tells the water control gate valve on the first line the pressure on the second line. Then if for example the pressure on the first line is low, then the water control valve on the second line opens and vice versa. Although not sure if such devices exists.

Here's a diagram of what I plan to do for reference.

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UPDATE: Did some more research and found out about solenoid valves. I think this is what I need to automatically turn on the supply from the pressure thank. So basically on the outlet of the pressure tank, I'll put a solenoid valve which is connected to a pressure switch on the first line. Hopefully it works.

Appreciate any suggestions/feedback.

Regards, Allen

  • 1
    Looks to me like you're overcomplicating this. Why not just run the water in from your provider to your water tank (as you already have it) and then only draw water out from the tank. Why do you ever need to 'switch over' and draw directly from the provider?
    – brhans
    Commented May 24, 2021 at 13:52
  • I was hoping to save electricity and prolong the life of the pump by doing this. We don't have low water pressure all day. It's only low on certain times and not everyday as well.
    – ads
    Commented May 25, 2021 at 3:49
  • 1
    You might check with your water provider to find out if this is in fact legal. I could see problems if somehow your tank got contaminated and then back fed into the mains.
    – Duston
    Commented May 26, 2021 at 13:57
  • The proper check valves should prevent that, @Duston, but it's a valid concern to bring up.
    – FreeMan
    Commented May 26, 2021 at 14:28


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