A pressure tank stores water under air pressure so the pump doesn’t start every time you open a tap. A waterlogged tank has lost its air, which causes rapid clicking and pressure swings. A tank with too little air acts the same way. You can check the air with the power off; repairs need a licensed installer.
Updated October 2026
Safety first: well pumps run on 230/240-volt circuits. Don’t open the pressure switch, control box or well cap wiring.
Waterlogged pressure tank symptoms
- The pump clicks on and off every few seconds while a tap runs.
- The pressure gauge jumps up and down quickly.
- Knocking on the tank sounds solid from top to bottom, with no hollow air space.
- Water sprays from the air valve on the tank.
The safe air check (power off)
- Turn the pump breaker off.
- Open a faucet and let it run until the water stops, so the tank is empty.
- Remove the cap on the tank’s air valve and check it with a tire gauge.
- Compare the reading to the tank label. Many labels call for air a little below the pump’s turn-on pressure.
- If water comes out of the valve, the inner bladder has likely failed. Stop there.
- Replace the cap, close the faucet, and turn the breaker back on.
Write the reading down for your installer. Recharging, repairing or replacing the tank is licensed work in Wisconsin.
Likely causes
| Likely cause | What you can safely check | Needs a licensed pro? |
|---|---|---|
| Failed bladder (waterlogged) | Water at the air valve; tank sounds full | Yes |
| Low air charge | Tire gauge reading below the label | Yes, to recharge |
| Tank too small for the household | Cycling started after adding people or fixtures | Yes |
| Rusted or leaking tank | Drips or rust at seams and fittings | Yes |
| Worn pressure switch | Chattering at the switch (don’t open it) | Yes |
Typical costs and life (estimates)
- Pressure tank: about $300 to $700 on average, up to $2,500.
- Pressure switch: about $100 to $350.
- Tank life: an estimated 5 to 15 years, depending on water and use.
Common questions
Why does my pressure tank keep getting waterlogged?
Older tanks without a bladder slowly absorb their air. Bladder tanks usually waterlog when the bladder fails, which often means replacement.
When you need a licensed professional
- The air charge is low or the bladder has failed.
- The tank leaks or is rusting through.
- Clicking continues after the tank checks out.
Wisconsin rules require a DNR-licensed pump installer for pump and pressure-tank work on a drinking-water well; check with DNR if you’re unsure.
Related
- Short cycling or won’t shut off
- Low or fluctuating pressure
- How long pumps and tanks last
- What well work costs
