Sump Pump Not Working? 8 Common Problems and How to Fix Them
A sump pump only matters on the day it is asked to work. In Ottawa that day is usually a spring-melt storm with the power flickering. If yours is running non-stop, staying silent, humming without pumping or tripping the breaker, this guide covers the eight most common sump pump problems, what causes each and how to fix it, plus the point where it is smarter to replace the pump than nurse it along.
It runs constantly and will not shut off
A pump that never rests usually has one of three problems. The float switch is stuck or has failed, so the pump is never told to shut off; the discharge line is clogged or frozen, so it cannot actually move water; or the pump is undersized for how fast your pit fills. Free the float or replace the switch and clear the discharge line. If the water level still never drops, you likely need a higher-capacity pump (PumpSpy). Constant running wears the motor out fast, so do not leave it.
It will not turn on at all
Start with power: confirm the pump is plugged in, the outlet is live and the breaker has not tripped. If power is fine, the float switch may be stuck against the pit wall (move it by hand to see if the pump kicks in) or the intake screen may be blocked with debris. Clear any obstruction and free the float. If it still will not start, the motor has probably failed and the pump needs replacing.
It hums but no water moves
A pump that hums or buzzes without pushing water almost always has a jammed impeller or an intake blocked by debris. Sometimes it is a failed motor or capacitor. Unplug it, then clear debris from the intake and impeller. Often the suction is simply blocked and a quick clean-out fixes it. If it still only hums once power is back on, the motor has likely burned out (Pentair).
It short-cycles, turning on and off rapidly
Rapid on-off cycling usually means one of three things: water falling back into the pit through a failing check valve; a float set too low; or a pit that is too small. Replace the check valve so pumped water cannot drain back, adjust the float to a sensible on-off range or fit a larger pit. Short cycling builds heat and burns motors out early, so it is worth fixing quickly (Gene Johnson Plumbing).
It trips the breaker
A pump that keeps tripping the breaker is drawing more current than the circuit can handle. The usual culprit is an impeller clogged or broken by grit and debris, which forces the motor to strain, but a shared or overloaded circuit and a failing motor can also be to blame. Clear the impeller and, ideally, put the sump pump on its own dedicated circuit rather than sharing it with other loads. If it keeps tripping after that, have an electrician or pump professional check the motor. This is the one problem where guessing is not worth the risk (Angi).
It is noisy: grinding, gurgling or loud humming
Some noise is normal, but distinct sounds point to distinct problems. Grinding or rattling usually means worn bearings or a damaged impeller; a loud hum without pumping points back to a jammed impeller or a failing motor; and a gurgling or slurping sound as the pump shuts off is water draining back through the discharge, which a quieter spring-loaded check valve can reduce. Match the noise to the cause before you assume the whole pump is done.
The discharge line is frozen or clogged (the Ottawa winter classic)
In an Ottawa winter the discharge line is the weak point. Water left sitting in the pipe freezes. The pump then has nowhere to send water and runs against the blockage until it overheats or the basement floods. Slope the line so it drains empty after every cycle, insulate any exposed sections, keep the outlet clear of snow and add a freeze-relief fitting if freezing is a recurring problem. Our complete sump pump guide covers winter discharge and sizing in more depth.
An empty pit or a bad smell
An empty pit is not always a fault. In a dry spell there may simply be no groundwater to collect. But a pit that stays bone dry through spring can mean the pump is not connected to your foundation drainage at all, which is worth checking. A musty or sewer-like smell is usually a dry trap or stagnant pit water: pour a bucket of water in to refill the trap and flush it. A persistent sewage odour is a different issue and points to your sewer line or a backwater valve rather than the sump.
When to repair and when to replace
A quality sump pump lasts about seven to ten years. If yours is past that, runs constantly, has already failed once during a storm or has no battery backup, replacement is the smarter money, ideally on a dry autumn day rather than mid-flood. Most outage failures come down to one thing: no backup when the power dropped. A new sump pump with a battery backup solves the problem the troubleshooting above only patches. We install and service pumps across Ottawa and every suburb.
The bottom line
Most sump pump problems trace back to a handful of parts: the float, the check valve, the impeller and the discharge line. Many are a quick fix, but a pump that has failed during a storm or is past its tenth birthday is telling you something. If you would rather have it checked before the next big melt, we diagnose and replace sump pumps free across Ottawa, from Kanata to Orléans. Request a free quote.
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