I have well water with a manifold inside the house that has a faucet, pressure tank, temperature sensor (for pump) and pressure relief valve. My current pump pressure is set to 60 which effectively goes from about 53 to 67.

I would like to bump up the pressure another 10 psi to improve reverse osmosis system pressure on the 2nd floor as well as the general improvement on the 3rd floor. I get about 10 psi drop every floor now. The pressure relief valve says it's set to 100 psi (at least from manufacturer), but it starts leaking around 70 psi.

First of all, is it advisable to go up another 10 psi? I assume the likelihood of leaks goes up and maybe the pump life is decreased. I'll probably also need to increase the pressure in the expansion tank. ~63-77 psi on the first floor (and lower on the above floors) doesn't seem to be extremely high to me, but I'm no expert.

Second, is there a tool to adjust the valve? It has two notches with a hole in the middle. A 5/8" or 11/16" slotted bit should fit, but those are hard to find and something like $20 online. How is this usually adjusted on the field?

  • Whether you can increases the pressure depends on the pump specs. You may also be able to exceed (over clock) pump spec by some X psi, but increasing too much beyond rated maximum will just use excessive energy.
    – Tyson
    Commented Nov 16, 2016 at 1:06

1 Answer 1


Most (or the ones I've met) well system pressure reliefs are non-adjustable. So if it leaks 30 PSI below rated pressure, I'd replace it (for less cost than your proposed tool purchase, as far as I recall.) Odds are that parts to rebuild yours will be more than simply buying a new one.

Toilet valves get wonky (or may) above 80 PSI or so, and any increase in well system pressure will reduce the effective capacity of the pressure tank (and should also be accompanied by adjusting the pressure in the pressure tank to a few PSI below the new low setpoint.) If your pump does not run at least a minute to refill the pressure tank (with nothing else drawing water) you should increase the size of the tank or add an additional tank.

  • This looks like what I have: amazon.com/STAINLESS-STEEL-PRESSURE-RELIEF-Pressure/dp/… The bottom cap screws off and is where it appears to be adjustable. Fair point on just replacing which will likely be cheaper. The pressure tank I have is the size of a regular expansion tank (about 5 gallons?) and the pump currently does not run for a minute before shutting off. It is one of those variable speed pumps (Grundfos). The control panel looks like this: comtermo.ru/userfiles/original/… and it allows up to 100 psi. Commented Nov 17, 2016 at 14:48
  • 1
    The variable speed pumps are supposed to be able to use a smaller expansion tank - if there is a procedure to check that it's operating correctly in the pump manual, follow that, as they toss the single-speed pump rules of thumb out the window. Looking up the valve you link I find a page that says "field adjustments are not recommended" - but if you wanted to try, grinding a flat hunk of steel to fit the slot on the valve and then grabbing it with a wrench would be one approach. A "drum brake adjusting tool" might be another means, if you get an inexpensive one with wide enough blades.
    – Ecnerwal
    Commented Nov 19, 2016 at 4:07

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