A sump pump running constantly is not normal, and it is not working correctly. A sump pump running constantly is one of the most common calls we get during rainy season. Your sump pump is designed to run when water accumulates in the pit, discharge that water away from the foundation, and shut off when the pit is clear.
The good news is that most causes of a constantly running sump pump in a Portland home are diagnosable and fixable. The important thing is not to ignore it. A pump running continuously is either failing to do its job, being overwhelmed by a drainage problem it was not designed to handle, or working against a mechanical failure that will cause it to burn out often at the worst possible moment.
I am Dylan with Better Basement and Waterproofing. We service sump pumps throughout Portland, Eugene, and Vancouver, and this is one of the most common calls we get during the rainy season. Here are the six most common reasons a sump pump running constantly becomes a problem in Portland homes.
CAUSE 1: THE FLOAT SWITCH IS STUCK OR POSITIONED INCORRECTLY
The float switch is the sensor that tells your pump when to turn on and when to shut off. It rises with the water level in the pit and triggers the pump when it reaches a certain height. When water drops back down, the float lowers and the pump shuts off.
If the float switch gets stuck in the raised position caught on the pump housing, tangled in the discharge line, or jammed against the wall of the pit the pump thinks water is always present and runs continuously even when the pit is empty.
How to check: Look inside the pit with a flashlight. Is the float hanging freely and able to move up and down without obstruction? If it is wedged against anything, carefully reposition it. Make sure there is at least a few inches of clearance between the float and the pit walls and the pump body.
A stuck float is one of the easiest fixes in sump pump maintenance and one of the most commonly overlooked. If repositioning the float resolves the continuous running, you have found your problem. If the pump continues running with the float clearly in the down position, the float switch itself may have failed and needs replacement.
CAUSE 2: THE SUMP PIT IS TOO SMALL FOR YOUR WATER VOLUME
Every sump pit has a finite capacity. If your basement receives more water than the pit can hold between pump cycles, the pit refills faster than the pump can empty it and the pump never gets to shut off.
This situation is especially common in Portland during extended heavy rainfall when the ground is fully saturated. When this happens a sump pump running constantly is not a mechanical failure — it is a drainage capacity problem. Portland’s clay soil holds water for days after a storm event, maintaining consistent pressure against the foundation and a consistent flow of water into the drainage system. A pump sized for normal conditions may be overwhelmed during peak demand.
It can also indicate that the interior drainage system is collecting more water than it was originally designed to handle which may mean new entry points have developed in the foundation that are adding to the water volume.
If your pump ran fine in previous years and has recently started running constantly during similar rainfall, the change in behavior suggests the water volume has increased. This is worth a professional inspection to identify whether new cracks or entry points have developed.
CAUSE 3: THE DISCHARGE LINE HAS A PROBLEM
Your sump pump discharges collected water through a pipe that exits the foundation and terminates away from the house. If that discharge line has any of the following problems, the water being pumped out can find its way back into the pit:
The discharge line terminates too close to the foundation. Water discharged within a few feet of the house percolates back into the saturated soil and re-enters the drainage system, creating a loop where the pump runs constantly but makes no progress.
The discharge line is clogged or frozen. A blocked discharge line means the pump is running but not actually moving water anywhere. This can cause the pump to overheat and fail quickly. In winter, discharge lines in Portland can freeze during cold snaps, blocking discharge completely.
The check valve has failed. A check valve is installed on the discharge line to prevent water from flowing back down into the pit after the pump shuts off. If the check valve fails or is missing, water drains back into the pit after every pump cycle and the pump immediately triggers again.
Check the exterior discharge point. Confirm water is actually exiting the line during a pump cycle. If nothing comes out, the line is blocked or frozen. Confirm the discharge terminates at least 6 feet from the foundation on ground that slopes away from the house.
CAUSE 4: THE PUMP IS UNDERSIZED FOR THE JOB
Sump pumps are rated by horsepower and gallons-per-hour capacity. A pump that is too small for the water volume it is managing will run continuously because it can never catch up with incoming flow.
Undersizing happens in two common scenarios in Portland. The original installer sized the pump for average conditions, not for peak rainy season conditions during a particularly wet year. Or the home’s water management situation has changed more cracks in the foundation, a failing exterior drainage situation, or a larger surface area now routing water to the pit than the original design accounted for.
If your pump is a quarter horsepower unit in a basement that collects significant water, upgrading to a half horsepower or higher capacity pump may resolve the continuous running issue. Read our guide on sump pump installation in Portland to understand how pumps should be sized for Pacific Northwest conditions.
Cause 5: Your Sump Pump Running Constantly May Mean It Is Near End of Life
A quality submersible sump pump lasts 7 to 10 years under normal use. One overlooked reason for a sump pump running constantly in older Portland homes is simply age.
As a pump ages, its motor efficiency drops. As a pump ages, its motor efficiency drops. It moves less water per minute than it did when new, even at the same horsepower. A pump that previously handled the water volume comfortably may struggle to keep up in its final years running longer and more frequently to accomplish what it used to do quickly.
If your pump is more than 7 years old and has started running more frequently than in previous seasons, age is a likely contributing factor. The smart move is proactive replacement before it fails during a storm rather than waiting for it to burn out.
At Better Basement and Waterproofing, we recommend testing your pump annually before the rainy season September is the ideal time in Portland. Read our guide on how long waterproofing systems last to understand maintenance timelines for all components.
CAUSE 6: YOUR WATER TABLE HAS RISEN
This is the least common cause but worth understanding. In some Portland neighborhoods particularly those in low-lying areas near Johnson Creek, the Columbia River floodplain, the Tualatin River basin, or areas near Amazon Creek in Eugene the seasonal water table rises significantly during wet winters.
When the water table rises close to the level of your sump pit, water seeps in through the pit walls and the surrounding soil continuously independent of surface rainfall and drainage system function. The pump runs constantly because it is managing a persistent upward pressure from below rather than collecting runoff from above.
A rising water table situation may require a larger pump, a deeper pit, or evaluation of the overall drainage strategy for the home.
What to Do When Your Sump Pump Is Running Constantly
A sump pump running constantly is a warning sign, do not ignore it.
Check the float switch first. It is the most common and easiest fix. Confirm it moves freely with nothing obstructing it.
Confirm the discharge line is clear and terminating correctly. Go outside during a pump cycle and confirm water is exiting the line.
Listen to the pump. A grinding, rattling, or high-pitched sound during operation suggests mechanical wear.
Note how old the pump is. If you do not know the installation date, a pump that shows any sign of wear and is over 5 years old is worth replacing proactively.
A sump pump running constantly for more than 24 hours without resolution needs professional attention. Call a professional if the cause is not obvious. A constantly running pump that you cannot diagnose quickly is not something to leave running for days. Motor burnout is a real risk and leaves your basement unprotected if it fails.
At Better Basement and Waterproofing, sump pump inspections and service are part of what we do throughout Portland, Eugene, and Vancouver. If your pump is running constantly and you are not sure why, we will find the cause.
Before hiring any contractor in Oregon, verify their license at the Oregon Construction Contractors Board. Our license is CCB# 239447.
Schedule your free sump pump inspection here
Better Basement and Waterproofing serves Portland, Eugene, Vancouver, and surrounding communities in Oregon and Washington.
