Disregard the old setup in the background, the old horizontal pressure tank is rusted out.

I have a shallow well and I want to set it up with two pressure tanks. Obviously the goal is to make the pump run less because it's kinda loud in my house.

Should I install a tee in the inlet of the smaller tank, connect the tee to the larger tank, and then equalize the air charge in the two tanks? What is the correct way to install this setup?

dual pressure tanks

  • 1
    Note that this won't make the pump run less, it will just make it come on less often. When it does run, it will have to run long enough to pump an additional ~40 gallons to fill that new tank.
    – gregmac
    Mar 3, 2015 at 15:33

1 Answer 1


You have the idea of it, I think, so long as you're not going for something cockamaimie like tying the air charge sides together. I don't actually think you are saying that; in any case, don't do that.

You just set those both 2 psi below the cut-in (ie, 18 PSI for a 20/40, 28 PSI for a 30/50 38 PSI for a 40/60 pressure switch setting, with the water side empty) and connect the water line to both tanks.

If the old vertical tank is still in usable condition, you could tap it in as well, though logic would call for a 1/4 turn ball valve; that might be a good idea for the new tank as well, since eventually it will be old, and may need service/replacement - price of the valve .vs. being able to service/replace the tank without shutting the whole system down - your call.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.