A pump that runs but never builds pressure has one of 7 problems. Here is how to find which one — starting with the easiest checks.
Check the pressure gauge while the pump runs. If the needle doesn't move at all, the pump may be running dry (no water), or the gauge itself may be faulty. If pressure rises slightly but never reaches cut-off, the pump is running but can't keep up with demand.
A failed check valve lets pressurized water drain back into the well the moment the pump stops. The pump must re-pressurize from zero every cycle and may never reach cut-off pressure. Listen for a gurgling sound after the pump stops.
A completely waterlogged tank provides zero storage — the pump runs continuously fighting to maintain pressure it can never hold. Test the Schrader valve.
The pump is pulling air instead of water. Pressure gauge barely moves. Pump trips on thermal overload after running. Let the well recover for 30–60 minutes and test again.
If cut-off is set above the pump's maximum shut-off pressure, the pump runs forever trying to hit a target it cannot reach. Check the switch setting against the pump's rated pressure.
Any air entering the suction pipe on a jet pump breaks the vacuum needed to lift water. Even a small crack at a fitting can prevent pressure from building.
Worn impellers move less water per revolution. Pressure builds slowly or plateaus well below cut-off. More common in pumps over 10 years old or those that have pumped sand.
Sometimes the simplest explanation — the gauge is stuck or faulty. Check water flow at a faucet. If water flows normally, the gauge is the problem, not the pump.
An undersized tank causes low pressure, short cycling, and early pump failure. Check yours free in 2 minutes.
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