Why Does Your Sump Pump Run Nonstop? (4 Causes & Fixes)

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A sump pump may continuously run due to several possible reasons. Firstly, if the pump's float switch is stuck in the "on" position, it will keep the pump running even when unnecessary.

Additionally, a malfunctioning check valve can cause water to flow back into the sump pit, triggering the pump to continue running. Another potential cause could be a high water table or excessive groundwater, leading to a constant influx of water into the sump pit.

Sometimes, a faulty or undersized pump may struggle to keep up with the water volume, causing it to run continuously as it tries to handle the excess. It is important to promptly identify and address the underlying issue to prevent potential damage and ensure the proper functioning of the sump pump system.

Understanding a Sump Pump

What is the Purpose of a Sump Pump, and How Does it Work?

You'll most likely find sump pumps installed in basements and crawl spaces. Both residential and commercial properties use these pumps to keep excess water out of the area. Flooding can cause many structural problems, including property and content damage. The pump is often placed inside a sump pit, a basin dug into the ground. When water flows into the hole, the sump pump turns on. It has an electric motor that powers an impeller, which spins rapidly, creating a centrifugal force that pushes the water out of the pit through a discharge pipe or hose. The water is then drained from the pit and to a storm drain or designated area on the property that is typically far from the foundation.

Components of a Sump Pump

• Sump Pump: The primary component of the system, the sump pump itself, is a mechanical device that includes an electric motor, impeller, and housing. It is responsible for pumping out water from the sump pit.
• Sump Pit: This is a specially constructed pit or basin usually made of plastic or concrete. It collects water from various sources, such as groundwater or drainage systems, and holds it until the sump pump is activated.
• Float Switch: The float switch triggers the sump pump to turn on and off based on the water level in the pit. It's typically a buoyant ball or float attached to a lever arm. The float drops when the water level rises, turning off the pump.
• Check Valve: Located in the discharge pipe or hose, the check valve ensures that water flows in only one direction. It prevents moisture from flowing back into the sump pit after it has been pumped out, reducing the risk of pump cycling or flooding.
• Discharge Pipe/Hose: The pipe or hose connected to the sump pump's outlet. It carries the water away from the sump pit to a suitable drainage location, such as a storm drain or designated area on the property.
• Backup Power Source: Some systems include a backup power source, such as a battery backup or generator, to ensure the sump pump operates even during power outages. This helps maintain the functionality of the pump when it's needed most.

These things work in tandem to ensure the sump pump systems work at 100% to prevent flooding and water damage. It is advised that routine maintenance be performed on the unit to ensure it is running correctly.

Why Does My Sump Pump Keep Running?

Cause 1: High water table

A high water table refers to the level at which groundwater is naturally present in the soil. Suppose the water table is close to or above the level of the sump pit. In that case, it can cause a sump pump to run continuously for several reasons: Constant water infiltration, inadequate drainage system, and insufficient pump capacity.

Cause 2: Improper sump pump sizing

Properly sizing a sump pump based on the specific requirements and conditions of the area is crucial to ensure its optimal performance and prevent continuous running or inadequate water removal. 

Cause 3: Malfunctioning float switch

A malfunctioning float switch can cause a sump pump to run continuously by failing to detect the water level in the sump pit properly. The float switch activates the pump when the water level rises and deactivates it when the water level lowers. When the float switch malfunctions, it may get stuck in the "on" position.

Cause 4: Clogged or frozen discharge pipe

In both cases, the sump pump runs continuously because it cannot properly remove the water from the sump pit. This can lead to increased energy consumption, excessive wear on the pump motor, and potential damage to the system if not addressed.

Troubleshooting and Fixes

• Check the Float Switch: Ensure that the float switch is moving freely and not obstructed. If it's stuck in the "on" position, try gently tapping or adjusting it to see if it disengages. If necessary, clean or replace the float switch.
• Inspect the Check Valve: Examine the check valve in the discharge pipe to ensure it is functioning properly. A malfunctioning check valve can cause water to flow back into the sump pit, leading to continuous pump operation. Replace the check valve if it's damaged or not functioning correctly.
• Assess the Discharge Pipe: Inspect the discharge pipe for clogs, obstructions, or freeze-ups. Clear debris or sediment from the line and ensure no blockages. If the pipe is frozen, use a heat source or insulation to thaw it. Address issues that may impede water flow.
• Evaluate Pump Sizing: Determine if the sump pump is appropriately sized for the volume of water it needs to handle. An undersized pump may continuously run as it struggles to keep up with the water inflow. Consider upgrading to a larger capacity pump if necessary.
• Check the Water Table: Assess if a high water table or excessive groundwater is causing the continuous operation of the sump pump. If so, additional measures, such as installing a higher capacity pump or improving drainage systems to manage the water effectively, may be needed.
• Verify Power Source: Ensure the sump pump receives a consistent power supply. Check the circuit breaker or fuse box to see if there are any electrical issues. If the pump has a backup power source, such as a battery, ensure it is functional and charged.
• Seek Professional Help: If troubleshooting the sump pump yourself does not resolve the issue, or if you are unsure about performing any steps, it is recommended to contact a professional plumber or sump pump specialist. They have the expertise to diagnose and address more complex problems with the sump pump system.

Maintenance and Prevention Tips

Regular maintenance is crucial for ensuring a sump pump's proper functioning and longevity. It is recommended to perform the following maintenance tasks periodically. First, inspect and clean the sump pit, removing debris or sediment hindering the pump's operation. Check the float switch to ensure it moves freely and is not obstructed. Test the pump by pouring water into the pit to verify its activation and pumping action. Inspect the discharge pipe for any clogs or obstructions, clearing them if necessary. Verify that the check valve is functioning correctly and replace it if needed. Test the backup power source, if applicable, to ensure it is operational. It is also important to consult the manufacturer's guidelines and recommendations for specific maintenance requirements.

About Princeton Plumbing Pros

Princeton Plumbing Pros is a professional company with decades of experience. They specialize in residential and commercial plumbing projects. To learn more about the company and to schedule a FREE estimate, please call (609) 917-7196.