What to Do If Your Sump Pump Fails After a Power Outage in St. Louis

If your sump pump fails after a power outage, immediately switch to its battery backup or a portable generator, test the pump by pouring water into the pit, clear any debris that might block its float switch or inlet, and if it still won’t run, call a qualified technician to avoid basement flooding.

Understanding How a Sump Pump Works

A sump pump is a small electric pump installed in a pit (called a sump basin) in your basement floor. When water collects in the pit, a float switch rises with the water level and turns the pump on. The pump pushes water through a discharge pipe away from your house. If power goes out, the pump stops unless you have a backup system.

Why Power Outages Cause Sump Pump Failures

When the electricity goes out, the main sump pump can’t run. Without a backup power source—like a battery backup unit or a generator—the pump can’t remove water that seeps in during heavy rain. This can let water build up in your basement and cause flooding or water damage.

 

Switch to Backup Power Immediately

 

• Locate your battery backup unit (usually next to the main pump). Make sure its battery is fully charged.
• If you have a portable generator, turn it on and plug the sump pump into it using a heavy-duty extension cord rated for outdoor use.
• Always use a generator outdoors and away from windows to avoid carbon monoxide poisoning.

 

Manually Test the Pump

 

• Pour a bucket of water into the sump pit until the float rises. The pump should start and push water out through the discharge line.
• Listen for the motor noise and watch the water flow. If nothing happens, the pump may be stuck, jammed, or electrically faulty.

 

Clear Debris and Inspect the Float Switch

 

• Turn off power at the breaker before reaching into the pit.
• Remove debris, gravel or mud that can block the pump’s inlet screen. This ensures water can enter easily.
• Check the float switch (a plastic or foam ball on an arm). It must move freely up and down. If it’s stuck, tap it gently or reposition it so it’s not trapped against the pump housing.

 

Check the Check Valve

 

• A check valve in the discharge line keeps pumped water from flowing back into the pit. Ensure it’s not leaking or stuck.
• If you see water running back into the pit after the pump stops, replace the check valve promptly to prevent constant cycling or flooding.

 

Inspect Electrical Connections and Breaker Panel

 

• Verify the pump’s electrical cord is firmly plugged in and not damaged.
• Check your breaker panel to make sure the circuit for the pump hasn’t tripped. Reset it if needed.
• If breakers trip repeatedly, there may be a wiring fault—stop and call a licensed electrician.

 

Prevent Future Failures

 

• Install or maintain a battery backup system: replace the battery every 2–3 years and test it monthly.
• Consider adding a water-level alarm that rings when the pit water rises too high.
• Schedule professional sump pump maintenance annually to check motor health, impeller condition, and electrical safety.

 

When to Call a Professional

 

• If the pump hums but won’t push water—this can indicate a seized impeller or motor failure.
• If you can’t clear a jammed float switch or replace a faulty check valve yourself.
• For electrical issues such as tripping breakers or damaged wiring.
• Whenever you feel unsure—getting help early avoids costly water damage.

Homes in St. Louis and Nashville face similar risks, so having a clear plan and backup power is vital. Regular checks and simple tests give you confidence that when storms strike, your sump pump will keep your basement dry.