How to Check and Set Your Pressure Tank

Why pressure tank air pressure matters

Your pressure tank holds a cushion of air next to a bladder full of water. That air is what pushes water to your faucets between pump cycles. When the pressure tank air pressure is set right, the pump runs in long, steady cycles and rests in between.

When the air charge is too low, the tank holds less usable water and the pump turns on and off in short bursts. That is called short cycling, and it is hard on both the pump motor and the tank. Checking the air is one of the few things a well owner can do to protect the pump.

Know your pressure switch setting first

Your pressure switch tells the pump when to start and stop. Common settings are 30-50, 40-60 and 60-80, and 40-60 is the most common. The first number is the cut-in, where the pump starts. The second is the cut-out, where it stops.

To find yours, look for a label or tag on the tank or near the switch, or check the paperwork from your last install. You can also watch the pressure gauge while someone runs water: the number where the pump kicks on is close to your low setting. If you are not sure, call us and we will help you figure it out.

Do not open the pressure switch cover. There is live electricity inside. You never need to take that cover off to check your tank.

How to check the air in your tank

All you need is an ordinary tire pressure gauge.

Turn the well pump breaker OFF at your electrical panel. It is often labeled well or pump.
Open a cold water faucet, ideally one near the tank, and let it run until the water stops completely. This empties the tank so you get a true air reading.
Find the air valve on the tank. It is a schrader valve, the same kind as on a car tire, usually on top under a small cap.
Press the gauge onto the valve and read it.
Compare it to your switch. The air should sit about 2 psi under the low number. On a 40-60 switch, that is around 38. On a 30-50, around 28. On a 60-80, around 58.
Close the faucet and turn the breaker back ON.

What your reading tells you

A little low

If the air is a few psi low, call us and we can set it to match your switch. Go slowly, recheck, and do not overshoot. If you would rather not, we are glad to do it.

Zero, or water comes out of the valve

If the gauge reads nothing, or water spits out when you press the valve, the bladder inside has likely failed and the tank is waterlogged. Adding air will not fix that for long. The tank usually needs to be replaced.

A good reading, but the pump still clicks on and off

Then something else is going on, like a leak, a worn switch, or a pump problem. That is a call for us.

When to call us

Call if the tank is waterlogged, the air will not hold, you see rust or leaks on the tank, or the pump short cycles even after the air is set. Also call if you just do not feel comfortable doing this yourself. That is fine. Our pressure tank replacement service installs Well-X-Trol pressure and holding tanks, balanced to your switch.

Short cycling for a long time shortens pump life, so it pays to catch it early. See how long a well pump lasts for more on that, and low water pressure on a well if weak pressure is your main complaint. If the pump itself seems to be the trouble, see well pump repair. Questions? Call 703-791-3981.

Questions we hear a lot

What should the air pressure be in my well pressure tank?

With the well breaker off and the tank drained, the air should read about 2 psi below your switch's cut-in number. On a 40-60 switch, that is around 38 psi. On a 30-50 switch, around 28.

How often should I check my pressure tank?

Once or twice a year is a good habit, and any time the pump seems to click on and off more than it used to. It only takes a few minutes with a tire gauge.

Can I check tank pressure with the water still in it?

Not accurately. With water in the tank, you are reading water pressure, not the air charge. Turn the breaker off and run a cold faucet until the water stops first.

What does it mean if water comes out of the air valve?

It usually means the bladder inside the tank has failed and the tank is waterlogged. Adding air will not hold for long. Call 703-791-3981 and we can replace the tank and set it to your switch.

How do I know what my pressure switch is set to?

Check for a label on the tank or nearby, look at your install paperwork, or watch the gauge to see where the pump kicks on. Do not open the switch cover to look. If you are unsure, call 703-791-3981.

What is short cycling on a well?

Short cycling is when the pump turns on and off in quick bursts instead of running steady cycles. It is often caused by a low air charge or a failed tank bladder, and it wears out the pump motor early.

Can I turn up my pressure switch for more water pressure?

Adjusting the switch means working inside the cover near live wiring, so please do not. If you want better pressure, call us. We can look at your tank, switch and pump and talk about options like a constant pressure system.

Do I need a bigger pressure tank?

A larger tank holds more water between cycles, so the pump starts less often. Whether it makes sense depends on your household and your pump. We can look at your setup and give you an honest answer.