Sump Pump Not Working? Troubleshooting Guide

Why won't my sump pump turn on at all?

When a pump is completely silent, start with the simplest cause: power.

• Check that the pump is plugged in. Vibration can slowly work a plug loose from the outlet.
• Look at the breaker for that circuit. A tripped breaker is common, especially if the pump strained recently.
• Many sump pumps use a piggyback plug, where the float switch plugs in and the pump plugs into the back of it. Test by plugging the pump directly into the outlet. If it runs, the float switch is the problem.
• If it's on a GFCI outlet, press the reset button. Pumps in damp pits trip GFCIs more than most appliances.

If power checks out and the pump still won't run, the motor may have failed or the float may be stuck. We'll cover both next. If you smell anything burnt or see scorching at the outlet, stop and call an electrician or plumber rather than resetting again.

Is the float switch stuck?

The float switch is the part that tells the pump when to turn on. As water rises, the float rises with it and triggers the motor. It's also the single most common failure point.

• Open the pit lid and look at the float. It should move up and down freely.
• A pump that shifted in the pit can press the float against the wall, holding it down so it never triggers.
• Debris, gravel, or sludge can block the float's travel.
• On older units the float can simply wear out or fill with water and stop floating.

Reposition the pump so the float has clear room to move, and clear out any debris. Lift the float by hand. The pump should kick on. If it does, you've likely found your problem. If the float moves freely but nothing happens, the switch itself may be dead and needs replacing.

Why does my sump pump run but not move water?

Sometimes the motor runs fine but the pit doesn't empty. That points to a flow problem, not a power problem.

• A clogged intake screen at the base of the pump starves it. Gravel and silt are the usual offenders.
• The discharge pipe can be blocked, frozen in a rare cold snap, or clogged with debris.
• A failed check valve lets pumped water flow right back into the pit, so the pump runs over and over without making progress.
• An airlock can form, trapping air so the impeller spins without pushing water.

Unplug the pump, pull it from the pit, and inspect the intake and impeller for buildup. Check that the check valve arrow points away from the pump, toward the discharge. If the pump hums but the impeller doesn't spin, it may be jammed or the motor may be done. At that point our sump pump service team can diagnose it quickly.

Why does my sump pump run constantly or short-cycle?

A pump that never shuts off, or one that snaps on and off rapidly, is telling you something is off.

Constant running usually means:

• A stuck float holding the switch in the on position
• A check valve that's failed, sending water back so the pit never truly empties
• Groundwater genuinely high enough that the pump can't keep up, which can point to a pit that's too small or a pump that's undersized

Short-cycling, where it turns on and off every few seconds, usually means:

• The on and off float settings are too close together
• The pit is too small for the volume coming in
• A waterlogged or failing float giving false readings

Running nonstop burns out a motor fast. If adjusting the float doesn't fix it, the pump or pit may be wrong for your home, and that's worth a professional look before the motor fails.

How do I test my sump pump before I need it?

The best time to find a dead pump is on a dry day, not during a storm. Testing takes five minutes.

• Pour a five-gallon bucket of water slowly into the pit.
• Watch the float rise. The pump should switch on before the water reaches the top.
• Confirm the water level drops and the pump shuts off once the pit is low.
• Listen for unusual grinding, rattling, or excessive vibration.

Do this at the start of every wet season and after any long dry stretch where the pump sat idle. A pump that sits unused for months can seize. While you're at it, make sure the discharge line carries water well away from the foundation, not back toward it. Folding sump testing into a regular plumbing maintenance routine means you're never guessing whether it works.

When should I call a plumber for my sump pump?

Some sump pump problems aren't DIY. Call a pro when:

• The pump is dead and power, the float, and the intake all check out
• It runs constantly and you can't find a stuck float or failed valve
• The motor hums but won't spin, or it's grinding and overheating
• The pit floods faster than the pump can keep up, suggesting it's undersized
• The pump is old and you simply can't trust it through another storm

We can repair a salvageable pump, swap a worn check valve, or install a properly sized replacement, and we'll talk through a battery backup if losing power during a storm is a real risk for your home. When water has already gotten loose, our water damage plumbing repairs crew can help with the cleanup and the plumbing fixes that prevent a repeat. Don't wait for the next heavy rain to find out the pump quit.