Troubleshooting
Well Pump Check Valve Failure: Symptoms and What They Mean
A check valve is a one-way gate that holds the water column in place when the pump stops. When it stops sealing — or sticks shut — the pump, the tank and your pressure gauge all show it.
On this page
A well check valve that leaks lets water fall back toward the well when the pump stops. You'll see the pressure gauge drift down with no water in use and the pump restart by itself, and you may hear a bang (water hammer) or get a burst of air when it starts. A check valve that sticks closed does the opposite: the pump runs but little or no water arrives. The valve near a submersible pump can only be replaced by pulling the pump.
What a check valve does
Franklin Electric, a major manufacturer of submersible well motors, says check valves hold pressure in the system when the pump stops and also prevent three things that damage pumps: backspin, upthrust and water hammer.[1] Most submersible pumps have one built in; installers add more on deep settings.
Positions follow Franklin Electric's installation guidance for submersible pumps. Jet-pump systems use a foot valve at the bottom of the suction pipe instead.
- Check valve at the pump — built into many submersible pumps; where it is not, a line check valve within 25 feet of the pump and below the drawdown level.
- Additional check valve — used on deeper settings, as the pump maker recommends. More valves than recommended should not be used.
- Standing water level — if the lowest check valve is more than 30 feet above it, a vacuum can form in the pipe and cause water hammer at the next start.
- Leak-back — a valve that doesn't seal lets the water column fall back down the well, which bleeds off tank pressure and can spin the pump backward.
Symptoms of a failing check valve
| What you notice | What's happening | Also check |
|---|---|---|
| Pump starts by itself with no water in use | Water is draining back toward the well, so tank pressure falls to cut-in | Running toilet, dripping fixture, leak in the buried line |
| Bang or thud in the pipes when the pump starts | Water hammer: a void formed in the pipe above a leaking valve, and the pump slams water into it | Loose pipe supports |
| Burst of air or cloudy water at the first faucet opened | Part of the pipe drained and filled with air between cycles | Other causes of air in the lines |
| Jet pump keeps losing its prime | The foot valve (the check valve at the bottom of the suction pipe) is leaking | Suction leaks |
| Pump runs, gauge barely moves | A check valve stuck closed, blocking flow | Broken pipe, low water level |
Franklin's troubleshooting table lists "check valve — stuck open" among the causes of a motor that starts too often and "check valve stuck closed" among the causes of one that runs continuously.[1] Square D's pressure-switch bulletin puts it this way for rapid cycling: with a faulty (open) check valve, water can flow back into the well, emptying the tank.[2]
The pressure-hold test
Safe to check
- Let the pump fill the tank and shut off. Write down the gauge reading.
- Close the valve on the house side of the tank tee, so no fixture can draw water.
- Leave everything alone for 20–30 minutes and read the gauge again.
- Reopen the valve.
| Result | Meaning |
|---|---|
| Gauge holds steady | The well side is holding. If the pump was restarting on its own, the water is leaving through the house — a fixture or a plumbing leak. |
| Gauge falls | Pressure is escaping between the tank and the well: a leaking check valve, a leak in the buried line or drop pipe, or a leak at the tank tee itself (look for drips). |
One thing that can hide a bad valve
Some systems have a second check valve near the tank. If the valve down the well leaks while the upper one holds, the gauge can stay steady — but the pipe between them drains. Franklin describes exactly this case: a vacuum forms in the pipe, and on the next start the water strikes the closed valve and the standing water above it, a shock that "can split pipes, break joints and damage the pump and/or motor." It adds that water hammer can often be heard or felt, and that when it is discovered the system should be shut down and the installer contacted.[1]
Why a leaking check valve is more than a nuisance
- Backspin
- With a failed check valve, water in the drop pipe runs back down when the motor stops and can turn the pump backward. If the motor starts while it is spinning backward, Franklin warns of impeller damage, shaft breakage and bearing wear.[1]
- Upthrust
- With a leaking or missing valve the pump starts against no head, lifting the impeller-and-shaft assembly. Repeated upthrust can cause early failure of the pump and the motor.[1]
- Water hammer
- Happens when the lowest check valve is more than 30 feet above the standing water level, or when a lower valve leaks and the one above holds.[1]
- Extra starts
- Every unnecessary start adds heat and wear; Franklin caps starts per day by motor size. See short cycling.
What a correct replacement looks like
If a contractor replaces a check valve, these are the manufacturer's rules to expect them to follow:[1]
- Positive-sealing valves only. Franklin says swing-type check valves "should never be used with submersible motors/pumps" because they react slowly and cause water hammer; spring-loaded or internal pump check valves close quickly.
- No drilled or drain-back valves. Drilling a valve to "let it drain" creates upthrust and water hammer problems.
- Placement. If the pump has no built-in valve, a line check valve within 25 feet of the pump and below the drawdown level. More valves on deeper settings per the pump maker — but not more than recommended.
- Variable-speed systems. Franklin recommends valves made for variable flow on constant-pressure systems.
Professional-only
Replacing a check valve on a submersible's drop pipe means pulling the pump — lifting pipe, cable and pump out of the casing with the power locked out. An accessible valve near the tank is a plumbing repair, but it still involves draining a pressurized system next to line-voltage equipment.
What it costs
HomeGuide lists a check valve replacement at $150–$200 and a foot valve at $150–$400, parts and labor.[3] Those figures fit a valve that is easy to reach. For a valve down the well, add the labor to pull and reset the pump; the same publisher reports $150–$300 per hour for a two-person well crew. Because most of that labor is shared, it's reasonable to ask what else should be inspected or replaced while the pump is out — see signs a well pump is failing.
Sources
- Franklin Electric. Submersible Motors: Application, Installation & Maintenance (AIM) Manual, 60 Hz. Accessed Sept. 28, 2026.
- Schneider Electric (Square D). Preventive Maintenance and Troubleshooting Guidelines for Class 9013F and 9013G Pressure Switches (Data Bulletin 9013DB0701, Dec. 2007). Accessed Oct. 8, 2026.
- HomeGuide. How Much Does Well Pump Repair Cost? (article dated Aug. 6, 2025). Accessed Oct. 8, 2026.
We cite manufacturer documentation and public agencies first. Read how we choose and check sources.