If your well pump loses pressure every time it shuts off, the check valve or pressure tank bladder is almost certainly to blame. Here is how to find out which one.
When a well pump shuts off, the pressurized water in the system should hold pressure until you use it. If pressure drops immediately or within a few minutes after shutdown, water is escaping somewhere — either back down into the well through a failed check valve, or the pressure tank has no air cushion to maintain pressure.
A check valve is a one-way valve that keeps water from draining back into the well after the pump stops. When it fails, every gallon of water the pump just pressurized drains straight back down. The next time you open a tap, the pump must start from scratch — repressurizing an empty system before any water reaches your faucets.
Symptoms: Pressure drops to zero within seconds of pump shutdown. Gurgling sound after pump stops. Pump takes a long time to build pressure from a dead start. Sputtering or air in water when pump first starts.
A healthy pressure tank stores water under pressure using an air cushion. When the pump shuts off, the air cushion maintains system pressure until you use that stored water. When the bladder fails, there is no air cushion — pressure drops the moment the pump stops because nothing is holding it up.
Symptoms: Pressure drops gradually over minutes rather than instantly. Pump cycles very frequently. Pressing the Schrader valve produces water instead of air.
| Symptom | Likely Cause |
|---|---|
| Pressure drops to zero instantly after shutdown | Failed check valve |
| Gurgling sound after pump shuts off | Failed check valve |
| Pressure drops slowly over several minutes | Waterlogged tank or slow check valve leak |
| Water from Schrader valve | Waterlogged pressure tank |
| Pump short cycles every few seconds | Waterlogged pressure tank |
On a jet pump, the check valve is on the suction pipe entering the pump — accessible above ground. Turn off the pump, drain system pressure, disconnect the pipe, replace the check valve ($10-25 at any hardware store), reconnect, and test. Total time: 30-60 minutes.
On a submersible pump, the main check valve sits inside the well casing above the pump. Replacing it requires pulling the drop pipe and pump from the well — a job for a well contractor in most cases.
An undersized tank causes low pressure, short cycling, and early pump failure. Check yours free in 2 minutes.
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