I am getting very low pressure due to my tank height in home. Input of tank got high pressure but not whole time. Something like below.

Normal situation - figure one

What my idea is directly connect input to low pressure end as below diagram. I have a doubt one way valve is reduced the pressure of high pressure end and low pressure end.

Modification - figure two

If I use like this, will I get high pressure when its available? (I do not have good idea how check valves are working)


  • Its not clear what kind of tank this is... Is it a pressure tank (like one that comes after a pump to maintain a pressure range) or just a holding tank? Also, are you measuring pressure with gauges?
    – aaron
    Apr 5, 2015 at 2:27
  • Anyway, check valves are one way valves that allow flow provided the Inlet side has higher pressure than the outlet sidr
    – aaron
    Apr 5, 2015 at 2:29
  • It just a holding tank. I don't have gauges to measure pressure, But I can feel huge diff between input and output. So basically check valves reduce pressure no. Do you have any idea about percentage or it is below 50%?
    – cdev
    Apr 5, 2015 at 4:12
  • 2
    Check valves do not reduce pressure, they actually help maintain it. In the setup you describe, it might work. However you will DEFINITELY need another check valve on the outlet of the tank to prevent the high pressure flow from backwashing in through the bottom, since there is no shuttoff/float valve there.
    – aaron
    Apr 5, 2015 at 8:48

2 Answers 2


Yes: your proposed cross-connect will maximize pressure on the outflow. But, as aaron commented, you will need to put a second check valve on the low pressure line between the cross connect and the tank to avoid losing pressure back to the tank (or, worse, blowing it out since there is presumably no shutoff valve on the tank outlet).


I'm not sure if you are still looking at this.

Your proposal will 'work' with the addition of a check valve to prevent the high pressure from back filling the storage tank. However, you may as well disconnect the storage tank as it won't do anything as the high pressure supply will always be dominant. The proposal you have drawn will result in you storing stagnant water in your tank.

Have you done basic checks for air locks or blockages etc?

  • The storage tank is there to provide water when the service line has low/no pressure.
    – feetwet
    May 16, 2015 at 13:01

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