Sump Pump Not Working — Emergency Guide

Water rising in your basement and the sump pump isn’t running? Act fast. Here’s how to diagnose and fix common problems.

Emergency First: Is Water Rising?

If water is actively rising:

1. Check if the pump has power (is it plugged in?)
2. Pour water into the pit to test if the pump activates
3. If it doesn’t run, you may need to bail manually or use a backup

Rental shops have portable pumps for emergency situations.

Quick Checks

Power

• Is the pump plugged in?
• Has the GFCI tripped? (Reset it)
• Has the breaker tripped?
• Test the outlet with another device

Float Switch Stuck

The float switch triggers the pump when water rises. If it’s stuck or caught on debris:

1. Remove the sump pit cover
2. Manually lift the float — does the pump run?
3. Clear any debris around the float
4. Make sure the float moves freely

Clogged or Frozen Discharge

If the pump runs but water doesn’t leave:

• Check the discharge pipe for clogs
• In winter, check for ice blockage
• Make sure the check valve is working (water shouldn’t flow back into the pit)

Common Problems

Float Switch Failure

The most common sump pump failure. The switch gets stuck, corroded, or mechanically fails.

Signs: Pump doesn’t turn on when water rises, but runs when float is manually lifted.

Fix: Float switch replacement ($15-40) or replace the whole pump if it’s old.

Pump Motor Failure

If the motor hums but doesn’t pump, or is completely silent despite having power, the motor may be dead.

Fix: Pump replacement ($100-300 for a new pump).

Check Valve Failure

If the pump cycles on frequently (short cycles), water may be flowing back into the pit because the check valve is stuck open.

Fix: Check valve replacement ($20-40).

Overwhelmed Pump

If water is entering faster than the pump can handle:

• The pump may be undersized
• There may be a new water source (broken pipe, new drainage issue)
• Heavy rain can temporarily overwhelm any system

Fix: May need a higher-capacity pump or additional pump.

When to Replace vs. Repair

Sump pumps last 7-10 years. If yours is older and failing, replacement is usually smarter than repair.

Replacement cost: $100-300 for the pump, $200-500 installed.

When to Call a Pro

• You can’t identify the problem
• Motor has failed
• You need a higher-capacity pump installed
• You want a battery backup system added
• Electrical issues

Prevention

• Test monthly: Pour water into the pit to trigger the pump
• Clean the pit annually: Remove debris
• Check the discharge line: Make sure it drains away from the house
• Consider a battery backup: Power outages often coincide with storms
• Consider a water alarm: $20 device alerts you to rising water

The Bottom Line

Most sump pump failures are float switch or power issues — both easy to check. If the pump itself is dead and it’s more than 7 years old, replace rather than repair. And consider a battery backup — pumps fail most often when you need them most.