Sump pump not working? Test it before the next storm
Quick answer
A sump pump that won't run risks a flooded basement, so test it before you need it: pour a bucket of water into the pit and confirm it switches on and discharges. If it doesn't, check that it has power (it's often on a GFCI outlet that tripped), that the float switch moves freely and isn't pinned against the pit wall, and that the discharge line outside isn't clogged or frozen. If power loss during storms is your worry, a battery backup is the fix.
Common causes
- No power — a tripped GFCI/breaker or an unplugged pump.
- A stuck or jammed float switch that can't signal the pump to run.
- A clogged intake screen or debris in the pit.
- A clogged, disconnected, or frozen discharge line.
- A failed or worn-out pump motor, or a power outage during a storm with no backup.
What to check first
- Confirm power — check the outlet (often a GFCI) and the breaker.
- Pour a bucket of water into the pit and watch: it should turn on and pump the water out.
- Make sure the float moves freely and isn't pinned against the wall or stuck with debris.
- Check the discharge pipe outside for clogs or ice.
- Listen for a humming motor that won't pump — that points to a jam or failed impeller.
When it's urgent
Heavy rain with a dead pump means imminent flooding — if water is rising and the pump is out, use a backup or wet/dry vacuum to buy time and keep water away from the furnace and electrical. Standing water near electrical equipment is a shock hazard, so cut power to affected areas if you can do so safely.
DIY vs. call a pro
You can likely DIY
- Resetting the GFCI/breaker and freeing a stuck float.
- Clearing debris from the pit, intake, and discharge line.
- Testing the pump with a bucket of water.
Call a pro for
- Replacing a failed pump.
- Adding a battery backup or a secondary pump.
- Redesigning discharge or drainage that can't keep up.
Estimated cost range
How HouseCue helps
HouseCue is a private, homeowner-first app that turns this from a one-time worry into a tracked plan. Snap a photo for an AI diagnosis, upload your inspection report to auto-build a handbook, and get seasonal reminders for your roof, HVAC, water heater, plumbing, and electrical — so nothing slips. Connecting with a pro is always optional and only when you choose.
Get started freeFrequently asked questions
How do I test my sump pump?
Slowly pour a bucket of water into the sump pit until the float rises. The pump should switch on, pump the water out through the discharge line, and shut off. If it doesn't activate or doesn't discharge, troubleshoot the power, float, and discharge line.
Why isn't my sump pump turning on?
The most common reasons are no power (a tripped GFCI or breaker) or a stuck float switch that can't signal the pump. Check the outlet and breaker first, then make sure the float moves freely and isn't jammed against the pit wall.
Do I need a battery backup sump pump?
If your area gets heavy storms — which often knock out power exactly when you need the pump most — a battery backup (or a water-powered backup) is strong insurance against a flooded basement during an outage.
Related guides
HouseCue guides are general educational information, not professional inspection, engineering, or contracting advice. Costs vary by market. For safety issues — gas, electrical, structural, or major water — contact a qualified professional.