Well Pump Runs But No Water: 5 Causes (and How to Fix Each)
When a well pump runs but produces no water, the five most common causes are lost prime, a failed check valve, a low water table, a broken underground pipe, and worn impellers. We recommend checking them in that order — the first two are free or cheap to fix and can be diagnosed in under 10 minutes.
If your faucets sputter and spray air before going dry, that confirms the pump is pulling air into the system. This guide walks through each cause by likelihood so you can identify the problem fast and know when it’s a job for a driller.
Before You Start: Confirm the Pump Is Actually Running
This guide is specifically for pumps that are running — motor humming, pressure switch clicking on. If yours is silent, that is a different problem. See our guide on a well pump not working at all for dead-pump diagnosis.
To confirm the pump is running:
- Listen at the pressure tank — you should hear the motor hum
- Watch the pressure gauge needle — it should move up when the pump kicks on
- Verify the well switch near the pressure tank is in the on position
- Check the double-pole circuit breaker (not tripped)
When the pressure switch clicks rapidly but zero water flows, Family Handyman’s well pump troubleshooting data points to problems external to the house — broken lines, failed check valves, or damaged well casing connectors. Continuous clicking with zero pressure buildup is your clearest signal that the cause is underground or inside the pump itself.
Video Guide
Video: “No Water, Low Pressure, Air in Water lines” by H2O Mechanic
Cause 1 (Most Likely) — Lost Prime
Lost prime means the pump has drawn in air and is spinning with nothing to move. Jet pumps (above-ground units) are the most vulnerable — one air leak in the suction line breaks prime entirely. The pump sounds normal but delivers zero water.
How to check: Open a faucet. If it sputters, sprays air, then stops, the pump is running on air.
How to re-prime a jet pump:
- Locate the priming plug on top of the pump housing (typically a 1/2” pipe plug)
- Fill the pump casing completely with water from a bucket or hose
- Replace the plug and restart the pump
- Water should flow within 60 seconds
Re-priming a jet pump takes 2–5 minutes and costs nothing as a DIY task. A service call for the same fix runs $150–$300.
Submersible pumps rarely lose prime, but if the water table drops below the pump intake, they can draw air. If the pump was recently serviced or you are in a dry stretch, check Cause 3 first before re-priming.
One important note: if re-priming attempts fail repeatedly — the pump loses prime again within minutes — stop running it and call a professional. Repeated unsuccessful re-priming attempts require expert diagnosis, not more DIY tries (Kocher & Geo Well Drilling). Running the pump dry for more than 15–30 minutes risks overheating the motor.
Cause 2 — Failed Check Valve
The check valve is a one-way valve on the pump outlet that holds water in the line between cycles. When it fails, water drains back into the well each time the pump shuts off. On the next startup, the pump pressurizes an empty line — it runs, you hear it, but nothing comes out.
Pressure gauge test: Watch the gauge as the pump runs. Pressure climbing to 20–30 PSI then dropping sharply back to zero — while the pump is still running — points to a leaking check valve. Lost prime, by contrast, produces zero pressure from the first moment the pump starts. That distinction matters for diagnosis.
Sediment suddenly appearing in your water is a secondary signal: check valve failure lets backflow stir up well sediment and pull it into the supply line, per Kocher & Geo Well Drilling.
Repair options:
- Jet pump check valve (on the inlet side): DIY-accessible, $10–$30 for the part, about 1 hour of work
- Submersible well pump check valve (typically 1–2 feet above the pump): requires pulling the pump from the well — this is not DIY
Cause 3 — Low Water Table (Drought or Seasonal Drawdown)
Drought conditions or heavy household water use — filling a pool, running irrigation through a dry summer — can temporarily drop the water table below the pump intake. The pump draws air and delivers nothing, but the pump itself is working perfectly.
Signs this is the cause: The problem started during a dry stretch or after unusually high water use. Neighbors on the same aquifer are also reporting low pressure.
Fastest test: Shut off the pump. Let the well rest 1–2 hours without any water use. Restart and open a faucet. If water flows normally, the well recovered — the pump is fine, the water table simply dropped and refilled.
Per EPA private well guidelines, private well owners are responsible for monitoring their own supply levels. If seasonal drawdown is a recurring problem, a well driller can lower the pump intake or deepen the well. Expect $500–$2,000 depending on depth and drilling conditions.
Drought drawdown is not a pump failure — do not assume the equipment needs replacement before testing the recovery.
Cause 4 — Broken Pipe or Fitting Underground
A cracked water line between the well and the house, or a damaged well casing connector, lets the pump circulate water underground without delivering any to your faucets. According to Family Handyman’s well pump repair guide, continuous pump operation without water flow points to exactly this: broken water lines, failed check valves, or damaged casing connectors.
How to identify it: Check the soil near the well head for unusually wet or soggy ground — a surface break leaves a wet patch. Watch the pressure switch replacement area — if the switch clicks on and off continuously while the pressure gauge reads zero after several minutes of pump running, suspect a major underground leak.
Above-ground fitting breaks at the well head are DIY territory. Underground pipe breaks and casing connector failures require a licensed well driller. Budget $500–$1,500 for underground pipe repair depending on depth and access.
Do not start digging before a driller confirms the break location. Knowing exactly where the pipe failed saves significant excavation cost.
Cause 5 (Least Likely) — Worn Pump or Impeller Damage
After 10–15 years of service, pump impellers wear and lose the ability to generate pressure. Sand or sediment ingestion accelerates that wear. The pump runs, the motor hums, but it cannot move water with any force.
Warning signs: The pressure gauge climbs only to 10–15 PSI — well short of the normal 40–60 PSI cut-out — even after several minutes of running. Output has been getting progressively weaker over months, not a sudden failure.
Before assuming impeller failure, try replacing the pump controller first. A failing controller can produce symptoms that mirror impeller wear, and replacement costs just $75 (Family Handyman). Same-brand models snap onto the existing box with no rewiring required.
For submersible pumps, impeller replacement requires pulling the pump: $300–$800 for the service call, plus $200–$800 for the replacement pump depending on HP and depth rating. A pump controller costs $75; a pressure switch runs about $25. If the pump is 10+ years old and the gauge reads 10–15 PSI, replacement is almost always more cost-effective than repair.
What to Expect After the Fix
| Cause Fixed | Time to Water |
|---|---|
| Lost prime | Within 60 seconds of restart |
| Check valve replaced | Immediate; full pressure in 1–2 cycles (2–5 minutes) |
| Low water table recovered | After 1–2 hour rest; monitor over the following week |
| Broken pipe repaired | Full pressure restored; run faucets 2–3 minutes to purge air from lines |
| Pump or impeller replaced | Full pressure at rated GPM (typically 5–25 GPM depending on pump size) |
If none of these causes fit or the fixes do not restore flow, see our well pump repair guide for the full diagnostic tree. A licensed driller can run a static water level test and perform a pump pull to determine what is happening below ground. For additional reference, common well pump problems covers failure patterns worth ruling out before calling for service.
FAQ
Why does my well pump run but produce no water pressure?
The most common reasons are a failed check valve letting water drain back between cycles, or lost prime causing the pump to spin on air. A pressure gauge reading of zero from the moment the pump starts points to lost prime or a broken pipe. Pressure that climbs to 20–30 PSI then drops sharply while the pump runs points to a leaking check valve. Less often, a low water table, underground pipe break, or worn impellers are the cause.
Can a well pump run dry and damage itself?
Running dry for more than 15–30 minutes overheats the motor and can permanently burn out the bearings. If you suspect lost prime or an empty line, shut the pump off immediately and diagnose the cause before restarting. Do not leave a pump running unattended when water output is zero.
How do I know if my well ran dry vs. my pump failed?
Let the well rest for 2 hours without any water use, then restart. If water flows normally, the well recovered — the water table dropped temporarily, and the pump is fine. If the pump still runs without water after the rest period, the pump or plumbing has failed. A well driller can confirm with a static water level test using a depth meter.
Is a well pump running with no water a DIY fix?
It depends on the cause. Re-priming a jet pump takes 10 minutes and costs nothing. Replacing a jet pump check valve is a $10–$30 part and about 1 hour of work. Anything involving pulling a submersible pump from the well — check valve replacement, impeller service, or full pump swap — requires a licensed well driller.
How long can a well pump run before damage occurs?
Running dry for more than 15–30 minutes risks permanent motor damage. Shut off the pump immediately if you suspect it is running without water. Work through the diagnostics above before restarting, and use our step-by-step well pump troubleshooting guide if you are unsure what to check next.