Direct answer: If your sump pump cycles every minute, the usual cause is short cycling: the float is set too close, the check valve is letting water fall back into the pit, or the discharge line is restricted so the pump never gets ahead of the water.
Most likely: Start by watching one full cycle. If the pit level drops, the pump shuts off, and water quickly rushes back in, suspect the sump pump check valve or discharge line before you blame the pump itself.
You want to separate three lookalikes fast: normal heavy-water operation, true short cycling, and backflow into the pit. Reality check: during storms, a sump pump can run often and still be fine. Common wrong move: unplugging it for long stretches just to stop the noise and then forgetting the pit is still filling.
Don’t start with: Do not start by buying a whole new sump pump. Rapid cycling is often caused by setup or backflow, not a dead motor.
The pump empties part of the pit, stops, then restarts within a minute or two even when rain is light.
Start here: Look for water dropping back into the pit through a bad sump pump check valve or a discharge line issue.
The float barely moves before the pump starts, and each run is very short.
Start here: Check float switch position, tether length, and whether the float is rubbing the pit wall or pump pipe.
Cycling gets much worse in heavy runoff, or the outside discharge area is icy or blocked.
Start here: Inspect the discharge line and outside outlet for restriction, ice, or recirculating water near the foundation.
The pump comes on often, but the pit level barely changes or drops slowly.
Start here: Suspect a partial clog, air lock, weak pumping, or a discharge problem before replacing the whole unit.
This is the classic every-minute pattern. The pump pushes water out, shuts off, then a column of water slides back into the pit and lifts the float again.
Quick check: Listen for a rush or splash into the pit a few seconds after shutdown, and watch whether the water level rises without new groundwater entering.
If the float has almost no travel, the pump starts and stops on a tiny water change. A float that rubs the basin wall can also trip erratically.
Quick check: With power off, move the float through its full range by hand and look for rubbing, tangling, or a tether that is too short.
A blocked, frozen, kinked, or undersized discharge path makes the pump work harder and move less water, so the pit refills or never fully clears.
Quick check: Check the outside discharge point for blockage, ice, or water dumping right back toward the house.
If the motor runs but the water level drops slowly, the pump may be worn, partially clogged, or simply not keeping up with incoming water.
Quick check: Watch whether the pit level drops decisively during a run. If it barely moves, the problem is beyond simple float adjustment.
The water pattern tells you whether you have backflow, a float problem, or simply heavy groundwater. That saves a lot of wrong guesses.
Next move: If you clearly see water fall back into the pit after shutdown, move to the check-valve and discharge checks next. If the pattern is still unclear, continue with the float inspection before assuming the pump is bad.
What to conclude: A quick restart caused by rising water after shutdown usually points to backflow. A quick restart with almost no water movement points more toward float setup or weak pumping.
A float that starts the pump on a tiny water rise will make a healthy pump act broken.
Next move: If the float now moves freely and the pump runs less often, the issue was float interference or poor adjustment. If the float moves normally but the pit still refills right after shutdown, go to the backflow and discharge checks.
What to conclude: A trapped or over-sensitive float causes true short cycling. If the float is free and the cycle is still rapid, the water is likely returning or the pump is not moving enough water.
A leaking check valve is one of the most common reasons a sump pump cycles every minute, especially when the restart happens soon after shutdown.
Next move: If you confirm water is draining back through the discharge after shutdown, replacing the sump pump check valve is the right next repair. If there is no sign of backflow, inspect the discharge line and outside outlet for restriction or recirculation.
Even with a good check valve, a blocked or poorly routed discharge can make the pump cycle constantly because water is not leaving cleanly or is coming right back to the foundation.
Next move: If you find and clear a blockage or redirect obvious recirculating discharge, the cycling should slow down once the pit level stabilizes. If the line is clear and the pump still barely lowers the pit, the pump or float switch is the likely repair path.
By this point you should know whether the problem is float control, backflow, or poor discharge. Act on the confirmed cause before rapid cycling burns up the pump.
A good result: A successful repair gives you a longer off-time between cycles, a clear drop in pit water level during each run, and no immediate restart from backflow.
If not: If rapid cycling continues after the confirmed repair, the pump may be undersized for current water load or there may be a larger drainage issue around the pit.
What to conclude: Short cycling that survives the obvious fixes usually means the pump is weak, the incoming water load is unusually high, or the drainage setup needs a closer look.
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Sometimes during extreme rain or snowmelt, yes. What is not normal is a very short run followed by an immediate restart from water falling back into the pit or a float that trips on a tiny water change.
Watch the pit right after shutdown. If the water level rises quickly and you hear water rush back in, the sump pump check valve is the first thing to suspect.
Yes. A float that rubs the basin wall, tangles with the cord, or has too little travel can start and stop the pump over and over with very little water movement.
Only long enough to inspect it safely, and only if the pit is not actively filling. Leaving it unplugged during wet conditions can turn an annoying noise into a flooded basement.
Not always. A weak pump is one possibility, but rapid cycling is more often caused by backflow, float setup, or a discharge problem. Confirm those first before replacing the whole pump.
Yes. If water cannot leave through the discharge line, the pump may run often, move little water, and struggle to lower the pit. Check exposed outdoor sections and the outlet area in freezing weather.