Well Pump Keeps Running and Won't Shut Off

Likely causes

1. 1

   Cause 1: Water is going somewhere

   The simplest cause: something in the house is using water, so the pump never gets ahead. A toilet tank that won't stop filling (the "cistern keeps running" search) is the classic one. So are a dripping outdoor hose, a softener stuck in regeneration, or a leak under the slab or in the yard line.

   Check by closing every tap and watching the pressure gauge. If the pump catches up and shuts off once the toilets are quiet, you found it. If the gauge falls with every fixture off, there's a leak.

2. 2

   Cause 2: A leak or broken pipe down the well

   If the house is tight but the pump still can't catch up, the water may be going back down the well. A split drop pipe, a leaking pitless adapter, or a check valve that won't close all let water run back into the casing. Boshart says the check valve's job is to stop water from draining back down the well when the pump stops. Goulds lists a faulty or wrongly installed check valve among the causes of a pump that delivers little or no water. These mean a pull, and our pitless adapter page shows one common leak point.

3. 3

   Cause 3: The pump can't reach cut-out pressure anymore

   A worn pump still moves water, just not enough to push the pressure to the shut-off point. Goulds lists excessive pump wear and debris binding the pump among the causes of low flow. Boshart notes that a pump with worn or clogged impellers may not keep up with demand.

   The same thing happens if someone raised the switch's cut-out higher than the pump can reach. Boshart's adjustment instructions turn the differential nut clockwise to raise the cut-out, and it's easy to overdo. If the problem started right after someone adjusted the switch, back the cut-out down until the pump shuts off on its own. See adjusting a well pump pressure switch.

4. 4

   Cause 4: The well is running low

   When the water level drops to the pump intake, the pump moves less water and pulls air. It runs and runs without building pressure. This shows up in dry spells, after long irrigation, or when a new pump is bigger than the well can supply. Goulds says to check the well's recovery and lower the pump if possible.

5. 5

   Cause 5: A jet pump lost prime

   On a jet pump, a pump that runs and builds no pressure has often lost prime. WAYNE's manual says to check priming first when a jet pump delivers little or no water, then look at causes like a suction leak, a clogged foot valve or a water level below the pump's reach. A jet pump running without water heats up fast, and WAYNE warns that running it dry will damage the pump. HomeGuide says jet pumps shouldn't run more than 2 to 3 hours at a time. Our how to prime a well pump page covers repriming.

6. 6

   Cause 6: Stuck pressure switch contacts

   Sometimes pressure reaches the cut-out and the pump keeps going anyway. That's the switch. Contacts can weld shut after years of arcing, or bugs and corrosion can jam the mechanism. The small tube or nipple that feeds the switch can also clog with sediment, so the switch never feels the pressure rise. A new switch is cheap: HomeAdvisor puts a pressure switch at $120 to $175 installed. See pressure switch problems.

7. 7

   Cause 7: A bad gauge

   A gauge that's stuck or lying will fool you. If the gauge reads above your cut-out and the pump is still running, either the switch is stuck or the gauge is reading high while the real pressure is still below cut-out. A new gauge costs $100 to $175 installed, per HomeAdvisor, and much less as a part.

Checks you can do safely

1. Turn the pump off at the breaker if it's been running a long time. Let it cool.
2. Close every tap and fixture, including outdoor hoses, the softener and any livestock waterers.
3. Turn the breaker back on and watch the gauge. Note where it stops climbing.
4. Compare that number to the switch setting. Common settings are 30/50 and 40/60 psi, and yours is often printed inside the cover or on the box. If pressure stalls well below cut-out, the pump or well can't keep up. If it reaches cut-out and the pump keeps going, the switch is stuck.
5. With the breaker off, watch the gauge for several minutes. A falling needle with everything off means a leak in the house or water draining back down the well.
6. Tap the switch cover lightly with the screwdriver handle while it runs at full pressure. If the pump stops, the contacts are sticking. Replace the switch rather than relying on that trick.

Fixes

A pump that runs dry once may be fine. One that does it every summer needs protection. Franklin's Pumptec cuts power to the motor when the load drops, guarding against dry wells and other low-flow conditions.

When to call a pro

Call a licensed well contractor if the house is tight and the pump still can't reach cut-out, the gauge falls with every fixture off, the pump runs hot or trips its overload, or you've replaced the switch and it still won't shut off. Those point to the pump, the check valve, the drop pipe or the well itself.

HomeAdvisor puts the average well pump repair at $974, with most jobs between $373 and $1,624, plus a house call fee of $100 to $150. If the pump is worn out, our well pump replacement cost page shows what a new one runs.