Sump pump repair in Knoxville, TN usually comes down to one of three parts: the float switch, the check valve, or the pump motor. A pump that will not start, runs constantly or hums without moving water is diagnosed in the pit, then repaired or replaced, and a battery backup can keep the basement dry through a power outage.
Updated October 2026
Why Sump Pumps Fail When It Rains
A sump pump sits idle for weeks, then runs hard through a storm. Floats stick, switches wear out, check valves fail and let pumped water fall back into the pit, and discharge lines freeze or clog. The worst failures come in a storm with the power out, when even a healthy pump stops.
We test the float, switch and pump, check the valve and the discharge route, and clear debris from the pit. Zoeller and Liberty Pumps build the submersible pumps we install most, with Watts check valves on the discharge. A basement bathroom's waste pump is a separate system, covered under sewer ejector pumps.
Signs Your Sump Pump Is Failing
Getting the Pit Pumping Again
- 1
Assess the pit
Water level, debris and power checked.
- 2
Test the float
Pit filled to watch the pump start and stop.
- 3
Check the discharge
Check valve and line inspected.
- 4
Repair or replace
Float, valve or pump replaced.
- 5
Retest
Several full cycles confirmed.
Float Switch Failure
The float switch turns the pump on when water rises and off when it drops. Tethered floats can tangle on the pump or the discharge pipe; vertical floats can stick in their track; and the switches themselves wear out. A stuck float leaves the pump off while the pit overflows, or on while it runs dry and burns up. We free or replace the float, set it so it can't catch on anything, and fill the pit with a bucket to watch the pump start and stop at the right levels.
Check Valve Replacement
The check valve on the discharge pipe keeps pumped water from falling back into the pit when the pump shuts off. When it fails, the pump re-pumps the same water over and over, cycling constantly and wearing out early. A loud thud when the pump stops is another sign of a check valve problem. We replace it with a quality valve, fitted with its arrow pointing away from the pit, and add a union so the pump can be pulled later without cutting pipe or disturbing the rest of the discharge line.
Battery Backup Pump
A battery backup pump sits in the pit beside the main pump, set a little higher, and runs on a deep-cycle battery when the power fails or the main pump cannot keep up. It is the difference between a dry basement and a flooded one during a storm that takes out the power. The battery needs a charger and periodic replacement, and the backup needs its own check valve. Some homes use a water-powered backup instead, which runs on city water pressure and needs no battery but uses water while it runs.
Storm Season and Knoxville Basements
Submersible, Pedestal or Battery Backup
The pit, the basement and the power supply decide the right combination.
| Type | Where it sits | Strength | Trade-off |
|---|---|---|---|
| Submersible | In the pit, underwater | Quieter, moves more water | Harder to service |
| Pedestal | Motor above the pit | Easy to service, long life | Louder, less capacity |
| Battery backup | Beside the main pump | Runs in a power outage | Battery upkeep |
What Sump Pump Work Costs Depends On
Parts decide most repairs; the pump type decides replacements.
The simplest repair.
Replaced with a union for future service.
Priced by horsepower and type.
Pump, battery, charger and its own check valve.
A frozen or clogged discharge line may need rerouting.
Sump Pump Repair & Installation Questions From Knoxville Homeowners
Why is my sump pump running all the time?
A stuck float switch, a failed check valve, or a high water table after heavy rain.
How often should I test my sump pump?
Before the rainy season and every few months: pour water into the pit and watch it start and stop.
Do I need a battery backup?
For a finished basement, it is the only protection when a storm takes the power out.
Can the sump pump drain into the sewer?
Generally no. Sump water should discharge outside, away from the foundation.
Why does my sump pit smell?
A dry pit can let odors through, or debris is decaying in it. Cleaning and a sealed lid help.
How long do sump pumps last?
It depends on how often they run; testing each season catches a failing pump early.
Other Emergency Jobs We Handle
Burst & Frozen Pipe Repair
Frozen pipe thawing and split copper line.
Burst & Frozen Pipe Repair overviewGas Leak Detection & Repair
Rotten egg smell and pressure test after repair.
Gas Leak Detection & Repair overviewWater Leak Detection
Hidden wall leak and meter running with fixtures off.
Water Leak Detection overviewBasement taking on water?
Call any hour. We get the pump running again.