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.
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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.
The two most common causes are a failed check valve (water drains back into the well after shutdown) or a waterlogged pressure tank (no air cushion to maintain pressure). Test the check valve by listening for water draining back after shutdown. Test the tank by pressing the Schrader valve.
A check valve is a one-way valve that prevents water from draining back down into the well after the pump shuts off. On submersible pumps it sits just above the pump in the well casing. On jet pumps it sits on the suction pipe entering the pump. A failed check valve allows all pressurized water to drain back into the well every time the pump stops.
After the pump shuts off, listen at the well cap or pressure tank for a gurgling or rushing water sound — that is water draining back down. Also watch the pressure gauge: a slow steady pressure drop after shutdown over 5-10 minutes suggests a check valve leak. An instant pressure drop to zero suggests a completely failed valve.
On jet pumps the check valve is accessible above ground and is a straightforward DIY replacement — typically a $10-25 part. On submersible pumps the check valve requires pulling the pump from the well, which is more involved and usually requires a well contractor.
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