Sump Pump Running Constantly? Why You Hear Water & How to Fix It

That quiet, humming sound from the basement is usually a sign your sump pump is doing its job, protecting your home from water damage. But when that hum turns into the constant sound of running or gurgling water, especially when it isn’t raining, it’s an unmistakable warning sign. An incessantly running sump pump isn’t just a noisy annoyance; it’s a symptom of an underlying problem that could lead to pump failure, higher energy bills, and a flooded basement.

Ignoring the sound of a constantly running sump pump is a gamble you don’t want to take. This guide will walk you through the most common reasons you hear water running in your sump pump and provide clear, actionable steps to diagnose and fix the issue before it becomes a catastrophe.

Understanding Your Sump Pump: The Basics of How It Works

Before diving into troubleshooting, it’s essential to understand the basic components of your sump pump system and their functions. A sump pump is a relatively simple machine designed for one critical task: to remove groundwater that accumulates in a basin (or sump pit) in your basement or crawlspace and pump it away from your home’s foundation.

A properly functioning system only activates when water in the basin reaches a specific level. The key components working together include the sump pit (the basin itself), the pump motor, a float switch that detects the water level, a discharge pipe to carry water away, and a check valve to prevent water from flowing back into the pit. When you hear it running nonstop, one of these components is likely compromised.

The Top 7 Reasons You Hear Water Running in Your Sump Pump

Several issues can cause your sump pump to run continuously. Pinpointing the exact cause is the first step toward a solution. Here are the seven most common culprits behind a sump pump that won’t shut off.

Reason 1: A Stuck or Malfunctioning Float Switch

This is by far the most frequent cause of a constantly running sump pump. The float switch is the trigger; as water fills the pit, the float rises, and when it hits a certain height, it activates the pump. If the switch gets stuck in the “on” position, the pump will run forever, even if there’s no water left to pump.

Float switches can get stuck for several reasons. Debris in the sump pit can wedge the float, or the pump’s vibrations can cause it to shift and press the float against the basin wall. Sometimes, the switch itself simply fails due to age or a mechanical fault.

Reason 2: A Failed or Missing Check Valve

The check valve is a crucial one-way gate located on the discharge pipe. Its job is to stop water in the pipe from flowing back into the sump pit after the pump turns off. If this valve fails, is stuck open, or was never installed, a significant amount of water will pour back into the pit right after being pumped out.

This backflow will immediately raise the water level, tricking the float switch into turning the pump back on. This creates a rapid, repeating process known as “short cycling,” where the pump turns on and off every few seconds or minutes. You’re essentially pumping the same water over and over, which puts immense strain on the motor.

Reason 3: A Clogged or Frozen Discharge Pipe

Your sump pump can run perfectly, but if the water has nowhere to go, it won’t do any good. The discharge pipe carries the water from your basement to a safe distance away from your foundation. If this pipe becomes clogged with dirt, leaves, or other debris, the pump will struggle to force water through the blockage.

In colder climates, a frozen discharge line is a common winter problem. If the end of the pipe is blocked by ice, the pump will run continuously, unable to expel water. This not only wears out the pump but can also lead to water backing up and overflowing the sump pit.

Reason 4: Continuous and Heavy Water Inflow

Sometimes, the pump is running constantly simply because there is a constant and high volume of water entering the pit. This can happen after prolonged, heavy rainfall or rapid snowmelt, which raises the local water table. In this scenario, the pump is just trying to keep up with the sheer amount of water.

However, a constant water source could also indicate a more serious problem, like a broken underground water pipe or a significant plumbing leak inside your home. If your pump runs nonstop even during dry weather, it’s crucial to investigate for a hidden leak that could be feeding water into your foundation drainage system.

Reason 5: An Undersized or Overwhelmed Pump

Not all sump pumps are created equal. If your pump is too small for the size of your sump pit and the volume of water it needs to handle, it will struggle to keep up. An undersized pump may run continuously during moderate to heavy rainfall because it can’t remove water as fast as it flows in.

This is a common issue in homes located in areas with high water tables or those that have experienced changes in local water drainage patterns. If your pump used to handle the load but now runs constantly, it may be a sign that conditions have changed or that the pump is losing efficiency with age.

Reason 6: A Broken Impeller or Clogged Intake

The impeller is a small, fan-like component inside the pump that spins to create the pressure needed to force water up the discharge pipe. If the impeller breaks or becomes damaged, the motor will run, but it won’t be able to move water effectively. You’ll hear the motor humming, but the water level in the pit won’t drop.

Similarly, the pump’s intake screen can become clogged with sediment, small stones, or other debris from the bottom of the pit. A clogged intake prevents water from entering the pump, causing it to run without pumping anything. This can quickly cause the motor to overheat and burn out.

Reason 7: A Leak in the Discharge Pipe Below the Check Valve

This is a less common but frustrating problem. If there is a crack, hole, or loose fitting in the section of the discharge pipe that’s inside the sump pit (below the check valve), a portion of the water being pumped out will spray right back into the pit. This leak essentially recycles the water, causing the pump to run much longer than necessary to empty the basin.

This issue can be hard to spot unless you are looking closely while the pump is active. It’s a wasteful process that adds unnecessary wear to your pump and inflates your electricity usage.

Your Step-by-Step Troubleshooting Guide

Now that you know the likely causes, you can follow a methodical process to find the problem. This guide will help you safely diagnose the issue. Remember to always prioritize your safety.

Step 1: Safety First! Disconnect the Power. Before you ever put your hands into the sump pit or handle the pump, you must disconnect it from its power source. Unplug the pump directly from the wall outlet. If it’s hardwired, turn off the corresponding breaker at your electrical panel.

Step 2: Observe and Listen. Before unplugging, take a moment to watch the pump in action. Is it running constantly without shutting off? Is it short cycling—turning on for a few seconds, shutting off, and then immediately turning back on? Listen for unusual grinding or humming noises, which could indicate a mechanical problem.

Step 3: Inspect the Float Switch. With the power off, carefully lift the pump out of the pit if necessary to get a clear view. Check the float switch. Is it tangled in the power cord? Is it pressed against the side of the basin? Make sure it can move up and down freely without any obstruction.

Step 4: Examine the Check Valve. To test the check valve, you’ll need to observe a pump cycle. Plug the pump back in and let it run. You can pour a few buckets of water into the pit to trigger it. Once the pump shuts off, listen carefully. If you hear a gurgling sound or see water rushing back into the pit from the pipe, your check valve has failed and needs to be replaced.

Step 5: Check the Exterior Discharge Line. Go outside to where your discharge pipe terminates. Is water flowing out freely when the pump is running? Look for any visible blockages like leaves, mud, or ice. If the pipe extends underground, you may need to disconnect it near the house to see if water flows out at that point, which would indicate a clog further down the line.

Troubleshooting Summary Table

For a quick reference, use this table to match symptoms with their likely causes and solutions.

Symptom	Possible Cause	Solution
Pump runs continuously, even with little or no water in the pit.	Stuck Float Switch	Untangle or free the float switch. If it’s faulty, replace it.
Pump turns on and off very frequently (short cycling).	Failed Check Valve	Inspect and replace the check valve to prevent backflow.
Pump runs, but water level in the pit doesn’t go down.	Clogged/Frozen Discharge Pipe or Broken Impeller	Clear blockage from the exterior discharge pipe. If clear, inspect the pump’s intake and impeller for clogs or damage.
Pump runs constantly during and long after rain.	Undersized Pump or High Water Table	Assess if a more powerful pump is needed. Check for continuous water sources.
Pump motor hums loudly but doesn’t move water.	Clogged Intake Screen or Damaged Impeller	Disconnect power and clean the pump’s intake screen. Inspect the impeller.

When to Call a Professional Plumber

While many sump pump issues can be resolved with some basic DIY troubleshooting, there are times when it’s best to call a professional. Plumbing and electrical work can be dangerous, and a mistake can lead to more significant damage.

You should call a licensed plumber if you encounter any of the following situations:

• You suspect an underground plumbing leak is the source of the water.
• You are not comfortable working with electrical components.
• You have replaced a part (like the check valve or float switch) and the problem persists.
• The issue appears to be a failed motor or significant mechanical problem.
• You believe you need a larger pump or a completely new system installed.

A professional has the tools and expertise to diagnose complex issues quickly and ensure the repair is done correctly, giving you peace of mind that your basement is protected.

Proactive Maintenance: Preventing Sump Pump Problems

The best way to deal with sump pump failure is to prevent it from happening in the first place. Regular maintenance is simple and can dramatically extend the life of your pump and prevent emergencies.

Once every few months, pour a bucket of water into the sump pit to confirm the float switch activates the pump and that it successfully removes the water. Annually, you should disconnect the pump and give it a more thorough inspection. Clean any mud or debris from the pit and wipe down the pump and its intake screen. Taking on small, regular maintenance tasks for your home’s critical systems is always a smart investment of your time. Just as you might research the right way to approach a home decor project, like figuring out how to hang an Anthropologie mirror to avoid wall damage, learning to maintain your sump pump can prevent a basement disaster.

A clean sump pit is also less attractive to pests. If you’re concerned about unwanted guests, it’s worth learning a few simple methods for how to keep bugs out of your sump pump. Furthermore, keeping the exterior discharge line clear is vital. Keeping the discharge line hidden can also protect it from accidental damage. There are many clever ways you can approach this, from landscaping tricks to decorative covers, if you want to know how to hide a sump pump discharge pipe.

Conclusion: Don’t Ignore the Sound of a Running Sump Pump

The sound of water constantly running in your sump pump is more than just a minor annoyance—it’s your home’s early warning system. It signals that a critical piece of equipment designed to protect your property is struggling, failing, or being overwhelmed.

By understanding the common causes, from a simple stuck float switch to a failed check valve or a clogged pipe, you are empowered to take action. Use the steps outlined in this guide to investigate the problem promptly. A few minutes of troubleshooting today can save you from the immense cost and stress of a flooded basement tomorrow.