A sump pump that runs for a few minutes after rain is doing its job. A sump pump that never stops — running for hours or days — is a pump heading for burnout, and a burned-out pump fails exactly when the next storm arrives.
This is the troubleshooting companion to our sump pump maintenance guide. Here are the six causes, in order of likelihood.
1. 🎈 Stuck Float Switch (Most Common)
The float rises with water and triggers the pump; it should fall and shut off as water drops. Floats jam against the pit wall, tangle in cords, or get stuck on debris — and the pump runs forever waiting for a water level that already passed.
Look into the pit: is the float free to move up and down? Clear any obstruction and make sure cords are routed away from the float's path. Tethered floats are the worst offenders; vertical rod floats jam less. If the float moves freely but the pump still will not stop, the switch itself has likely failed.
2. 🔄 Failed Check Valve
The check valve on the discharge pipe stops pumped water from flowing back into the pit. When it fails, the pump pushes water up, the water falls back down, the float rises again — an endless cycle that runs the pump to death.
Listen: if you hear water rushing back into the pit right after the pump cycles, the check valve is the culprit. It is an inexpensive part and a straightforward replacement — and the arrow on the valve body must point away from the pump (a backwards check valve causes this exact symptom).
3. 💧 Groundwater Overwhelming the Pump
Sometimes the pump is fine and the water is the problem: a high water table, broken exterior drainage, or a discharge line dumping water right back against the foundation can keep the pit refilling faster than the pump empties it.
Walk the discharge line: it should empty well away from the foundation — not into a clogged dry well or right back at the house. In East Tennessee's clay soil, grading and gutter extensions matter as much as the pump. If inflow genuinely exceeds the pump's capacity, you may need a higher-capacity unit or a second pump.
4. 📏 Wrong Pump Size or Worn Impeller
An undersized pump runs constantly trying to keep up; a worn impeller (from years of silt and debris) moves less water than it used to, with the same nonstop result.
If the pump is 7+ years old and runtime has been creeping up, wear is likely. Sump pumps average 7–10 years. A pump that cannot keep up anymore is telling you it is time — see what to do before the plumber arrives if it fails outright.
5. 🔌 Switch or Wiring Failure
On pumps with separate piggyback float switches, the switch itself can fail closed — the pump runs regardless of water level. Unplug the switch and plug the pump directly: if the pump stops responding to the switch entirely, replace the switch (much cheaper than the pump).
Also check for a switch cord wedged under the pump or pinched against the pit — mechanical interference mimics electrical failure.
6. ⚠️ The Burnout Risk: Why Speed Matters
A continuously running pump overheats. Thermal overload may trip and reset in cycles — each cycle cooking the motor a little more — until it dies completely. A $15 check valve ignored today becomes a $300 emergency pump replacement during the next storm.
If the pump is hot to the touch, making grinding noises, or tripping its thermal reset repeatedly, stop using it and call for service. Running a dying pump risks it seizing mid-storm. Emergency service exists for exactly this scenario.
Frequently Asked Questions
Is it normal for a sump pump to run constantly during heavy rain?
Running frequently during heavy rain is normal. Running nonstop for many hours after rain stops — or cycling every few seconds — is not, and points to one of the causes above.
Why does my sump pump keep running after the water is gone?
Usually a stuck float switch or a failed check valve letting discharged water flow back into the pit. Check the float's freedom of movement first.
Can a sump pump burn out from running too long?
Yes. Continuous operation overheats the motor, and repeated thermal-overload trips degrade it further. A pump that never rests is a pump approaching failure.
How long should a sump pump last?
7–10 years on average. Pumps that run frequently (high water table areas) wear faster. If yours is past 7 and struggling, budget for replacement rather than repeated repairs.
Pump That Won't Quit? Don't Let It Burn Out
A nonstop pump is on borrowed time — fix the float or check valve now, or replace the pump on your schedule instead of the storm's. Call Best Value Plumb and we'll connect you with a local plumber in Mary Esther, Oakland Park, or Knoxville.
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