Sump Pump Not Working? Quick Checks Before the Next Storm

Sump pump not working is an emergency when rain is coming, because the basement can flood within hours. Most failures come from no power, a stuck float switch, a jammed impeller, a bad check valve or a frozen or blocked discharge line. Work through the checks below with the pump unplugged, and arrange a repair or replacement the same day.

Sump pump not working: safety first

Water and electricity are a dangerous mix. Do not stand in water while touching a pump or its cord. Unplug the pump before you handle it, and if the basement is already flooded and the outlet or panel is wet, stay out and call an electrician or emergency service.

Quick facts: sump pump not working
Time needed	15 to 45 minutes
Tools	Flashlight, bucket, screwdriver, wet/dry vacuum
Difficulty	Easy to moderate
Safety	Unplug the pump before handling it; keep out of standing water near live outlets

Common reasons a sump pump fails

Symptom	Likely cause	What to try
Silent, pit filling with water	No power, tripped GFCI or breaker	Check the outlet and reset it
Hums but does not pump	Jammed impeller or failed capacitor	Unplug, clear debris, or replace the pump
Runs but moves little water	Clogged intake or failed check valve	Clean the intake, check the valve
Runs constantly	Float stuck, check valve failure, high water table	Free the float, inspect the valve
Float will not rise	Float tangled or stuck against the pit wall	Reposition the float or replace the switch
Water frozen in discharge pipe	Blocked or frozen outlet line	Thaw gently and clear the discharge

Step by step

1. Check power. Plug a lamp into the outlet. Reset the GFCI and look at the breaker.
2. Check the float. Lift it by hand with the pump plugged in. If the pump starts, the float was stuck or tangled.
3. Pour water in. Slowly add buckets of water to the pit to test whether the pump starts and empties it.
4. Unplug and inspect. Lift the pump out, remove debris from the intake screen and the impeller, and rinse.
5. Check the discharge. Make sure the outlet pipe outside is not blocked, frozen or kinked, and the check valve is not stuck.
6. Reinstall level in the pit, plug in and test again.

Buying time while you wait

Use a wet/dry vacuum or bucket to remove water from the pit, put valuables and electronics up off the floor, and move stored items from low shelves. A temporary utility pump with a hose to a safe drain can help. If rain is imminent and the pump is dead, a plumber can often install a replacement quickly.

Replace instead of repair

If the pump is old, the motor hums but does not pump, or the housing is cracked, replacement is usually more sensible than repair. A sump pump not working at its end of life should be replaced before the next rain, ideally with a check valve and a battery backup.

Short cycling, and what it tells you

A pump that switches on and off every few seconds is short cycling. Common causes are a failed check valve that lets water drain back into the pit, a float set too close to the pump, or a pit that is too small for the pump. Left alone, short cycling wears the switch and motor quickly. A plumber can fit a new check valve, adjust the float or resize the pit.

What to keep near the pit

Keep a flashlight, a bucket, a wet/dry vacuum and a spare check valve near the pit, and write the pump model number on the wall. If you need a quick replacement, the model number saves time at the shop or on the phone.

Prevention

Test the pump before storm season, clean the pit once a year, check the discharge outlet, and consider a battery backup. A sump pump that runs constantly even in dry weather points to a bigger water problem that a plumber should assess.

Related reading

• How Long Do Sump Pumps Last? Lifespan, Signs and Upkeep
• How Does a French Drain Work? Design, Limits and Maintenance
• Water Seeping Through Basement Wall: Causes and Lasting Fixes
• Practical Guide: What to Do When Your Basement Floods

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