How Much Pressure Should Be in a Well Pressure Tank?

1. The Two Pressures in Every Well System

People mix these up all the time, so let's separate them:

• System (water) pressure is what you see on the gauge near your tank. It's controlled by the pressure switch, which turns the pump on at the cut-in pressure and off at the cut-out pressure. A "30/50" switch starts the pump at 30 PSI and stops it at 50 PSI.
• Tank air precharge is the air sealed above the rubber bladder or diaphragm inside your tank. That air cushion is what pushes water out to your faucets between pump cycles. You can only measure it at the air valve on top of the tank, and only when the tank is empty.

The precharge sits just under the cut-in so the tank delivers every drop of usable water right up to the moment the pump restarts, with no gap in pressure.

2. Well Tank Precharge Chart

Find your switch setting (often printed inside the switch cover or on the tank label; your installer can confirm it) and match it to the precharge:

Pressure switch (cut-in / cut-out)	Tank air precharge	Typical use
20 / 40 PSI	18 PSI	Older systems, low-head pumps
30 / 50 PSI	28 PSI	Very common residential setting
40 / 60 PSI	38 PSI	Very common; stronger shower pressure
50 / 70 PSI	48 PSI	Larger homes, irrigation, multi-story

Rule from AMTROL's well tank guidance: set precharge 2 PSI below cut-in. Always confirm the maximum working pressure on your own tank's label.

3. How to Check Your Well Tank Pressure (Step by Step)

You need a standard tire pressure gauge, and an air compressor or bike pump if you need to add air.

1. Turn off the power to the pump at the breaker (usually a double-pole breaker labelled "well" or "pump").
2. Drain the pressure. Open the faucet nearest the tank, or the tank's drain valve, until the gauge reads 0 PSI and the water stops.
3. Remove the cap from the air valve on top of the tank (it looks like a tire valve).
4. Read the pressure with your tire gauge.
5. Adjust. Add air until you reach cut-in minus 2 PSI, or press the valve core to let air out if it's high.
6. Close the faucet, restore power, and watch the gauge. The pump should start near the cut-in and stop near the cut-out.

4. What Your Readings Mean

What you find	What it usually means	What to do
Within 1–2 PSI of target	Tank is healthy	Re-check next year
A few PSI low	Normal slow air loss over time	Top it up; re-check in a month. If it drops again, the bladder may be leaking
0 PSI, or it won't hold air	Bladder or tank shell has failed	Replace the tank
Water comes out of the air valve	Bladder has ruptured; tank is waterlogged	Replace the tank. Adding air won't fix it
Precharge higher than cut-in	Set wrong at install, or switch was changed	Lower to cut-in minus 2 PSI

Not sure which tank you need? Our guide on how to choose the right well pressure tank covers sizing and drawdown in detail.

5. Why the Right Pressure Protects Your Pump

The air charge decides how much water your tank can hand out before the pump has to start again. That usable amount is called drawdown. Even a correctly charged 44-gallon tank only delivers roughly 13–15 gallons between cycles, depending on the switch setting. When the air charge is low, drawdown shrinks further and the pump starts more often.

Every start is the hardest moment in a pump motor's life: it pulls several times its normal running current and builds heat in the windings. A pump that should start a few times an hour starts dozens of times instead. That's how a $1,500–$3,000 pump replacement shows up years early.

Signs your tank pressure is off:

• The pump clicks on and off every few seconds while water runs (short cycling)
• Pressure surges and drops in the shower
• Faucets spurt or the gauge needle jumps
• Higher electric bills with no other explanation

If your water stops completely instead, start with our checklist: Why Has My Well Suddenly Stopped Working?

6. Can I Turn Up My Water Pressure?

Often, yes. Moving from 30/50 to 40/60 is a common upgrade. But three things have to line up first:

1. Your pump must be able to reach the new cut-out. If the well level is low or the pump is worn, it may never reach 60 PSI and will run non-stop, which destroys it.
2. The tank precharge must be raised to match (38 PSI for 40/60).
3. Your tank and plumbing must be rated for the higher pressure.

If you want city-like pressure that doesn't swing at all, ask about a constant pressure (variable speed) system. These adjust pump speed to demand. They use different tank settings, so follow the drive manufacturer's specification rather than the chart above.

7. Frequently Asked Questions

What should the air pressure be in a well tank with a 40/60 switch?

38 PSI, measured with the pump off and the water pressure drained to zero. The rule is 2 PSI below the cut-in pressure.

What should the air pressure be in a well tank with a 30/50 switch?

28 PSI, measured with the pump off and the tank drained of water.

Why does my well pump turn on and off every few seconds?

Rapid cycling is most often caused by a low air charge or a failed bladder in the pressure tank. It can also come from a leak or a faulty pressure switch. It wears out the pump quickly, so have it checked soon.

How often should I check my pressure tank?

Once a year is a good habit. Tank manufacturers recommend checking the precharge at least annually, and any time you notice the pump cycling more often or pressure swinging.

Can I check the tank pressure without draining the water?

No. With water in the tank, the gauge reads system pressure instead of the true air charge. Turn off the pump and drain pressure to zero first.