Sump Pump Keeps Running? Here’s How to Fix It

Last updated: September 30, 2026  ·  Reviewed by the Sump Pump Central editorial team.

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A sump pump running non-stop wears out its motor far faster than normal — and many of the common causes can be fixed in under an hour once you know what to look for. A sump pump that runs continuously — even when it is not raining — is one of the most common problems homeowners face. It is also one of the most urgent: a constantly running pump burns out its motor in a fraction of its normal lifespan, and the underlying cause is usually something that will flood your basement if left unfixed. This guide walks you through the diagnostic process in a logical, step-by-step order, so you can isolate the problem in minutes and fix most causes yourself in under an hour.

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First: Is It Really Running Continuously?

Before anything else, confirm what you are actually seeing. “Running constantly” usually means one of three different patterns, and each points to different causes:

• Pump never shuts off. Motor is running non-stop for minutes or hours. Usually a stuck float or genuinely overwhelmed pump.
• Pump cycles every few seconds (short cycling). Pump runs 20 seconds, off for 5-10 seconds, runs again. Classic check valve failure.
• Pump cycles every 1-5 minutes non-stop. Could be high water table, oversized pit, failed check valve, or groundwater infiltration.

Watch the pump for 2 to 3 minutes before you start diagnosing. The pattern will tell you where to look first.

Why Is My Sump Pump Running Constantly? 8 Causes and Fixes

There are eight main reasons a sump pump runs non-stop. Most are easy to fix yourself — only one or two require a plumber or pump replacement. We have ordered them by likelihood so you can work through them in the most efficient sequence.

1. The Float Switch Is Stuck in the ON Position

The float switch tells the pump when to turn on and off. If it is stuck in the up (“on”) position — often because it is wedged against the pit wall, tangled in the power cord, caught on the discharge pipe, or jammed by debris — the pump runs continuously even when there is no water to remove. This is one of the most common causes, and the easiest to fix. How to diagnose: Unplug the pump (safety first). Reach into the pit and find the float. It should move freely up and down. If it is stuck up, something is holding it there. If it is a tethered float, it commonly catches on the pit wall in narrow pits. How to fix: Clear whatever is holding the float. Reposition the pump so the float has at least 2 inches of clearance on all sides. If the pit is too narrow for a tethered float to travel freely, upgrade the pump to one with a vertical float switch, such as the Zoeller M57 (the vertical-float version of the Zoeller M53). For details on how float switches work and when to replace them, see our sump pump float switch guide.

2. The Check Valve Is Missing, Failed, or Stuck Open

The check valve prevents water from flowing back into the pit after the pump shuts off. Without it, the water column in the discharge pipe drains back down, triggering the float again within seconds, causing non-stop cycling (“short cycling”). A failed check valve that is stuck open has the same effect. This is the #2 cause of a constantly running pump. How to diagnose: Look at the discharge pipe above the pump. A check valve is a roughly 4-6 inch long cylinder, usually with a clear window or a visible arrow indicating flow direction. If you cannot identify one, it is likely missing. If present, listen when the pump shuts off: a healthy check valve closes with a soft click. A failed one will let water audibly rush back into the pit. How to fix: Install or replace the check valve. This is a 20-minute DIY job. See our best sump pump check valves guide for recommended models and a full installation walkthrough.

Quick fix: Our top check valve pick is the Zoeller 30-0181, a 1-1/2″ PVC check valve that fits most residential discharge pipes. Check price on Amazon →

3. The Float Is Set Too Low

If the float activates the pump when the pit is only a quarter full, the pump triggers far more often than it needs to — sometimes appearing to run constantly during any period of light water intrusion. This is not a failure; it is an adjustment problem. How to fix: On tethered floats, lengthen the tether so the float has to rise further before activating. On vertical floats, check your pump manual for adjustment instructions. You want at least 6 inches of water depth between the “off” and “on” points for efficient cycling.

4. The Discharge Line Is Undersized, Kinked, or Blocked

If water cannot exit the discharge pipe fast enough, the pump runs continuously trying to keep up with inflow it cannot fully evacuate. A kinked pipe, undersized diameter, partial blockage, or frozen section will all cause this. How to diagnose: Trace the discharge pipe from pump to exterior. Look for kinks, crushed sections (common in older installs), or visible blockages. In winter, check for ice plugs. Also verify the pipe diameter — it should be at least 1-1/4″ for a 1/3 HP pump, 1-1/2″ for a 1/2 HP pump. How to fix: Straighten any kinks, clear blockages, and increase pipe diameter if undersized. For winter freeze-prevention, install an IceGuard fitting at the exterior discharge point or insulate exposed sections — see our full guide on stopping a sump pump discharge line from freezing for cold-climate options.

5. The Pump Is Undersized for the Water Volume

If your pump’s pumping rate is less than your water inflow rate, the pump will run continuously and still never catch up. This is common in homes that have developed drainage problems over time (failed drain tile, new grading issues, etc.) or where a contractor installed the minimum-spec pump originally. How to diagnose: Time how fast your pit refills when you pump it dry. If the pit refills to the activation point in under 60 seconds and this is normal (not during a flood), your pump cannot keep up with inflow. How to fix: Upgrade to a higher-capacity pump. See our sizing guide to pick the right GPH rating for your conditions. For most homeowners dealing with persistent high flow, stepping up from 1/3 HP to 1/2 HP is the right call. Our top 1/2 HP pick is the Wayne CDU980E (5,245 GPH at 0 ft head) — check current price on Amazon →.

6. High Water Table or Seasonal Groundwater Surge

If the ground around your home is naturally saturated — especially in spring, after prolonged rain, or in homes built near streams and wetlands — groundwater continuously seeps into your pit through the weep holes in the pit liner. This is expected behavior and not a pump problem. However, the pump running constantly in these conditions still wears it out faster. How to fix: You cannot eliminate a high water table, but you can install a larger pump to handle longer cycle times with less strain, add a backup battery pump so a primary failure does not flood you, and consider exterior waterproofing (French drain, regrading) to reduce water reaching the foundation in the first place.

7. Foundation Cracks or Drain Tile Problems

If water is entering your pit through cracks in the foundation, failed drain tile (the perforated pipe that runs around your foundation footings), or damaged weeping tile, you have a building envelope problem, not a pump problem. The pump is doing its job — it is just fighting a losing battle. How to diagnose: Look for visible cracks in the basement walls and floor, especially near corners and where walls meet the floor. Water staining, efflorescence (white powdery deposits), or damp spots indicate active moisture paths. A pump running constantly in dry weather is a strong signal of this. How to fix: This is a specialist job. A foundation contractor or basement waterproofing company can evaluate and repair. Costs range from $500 for simple crack injection to $15,000+ for full drain tile replacement. Not cheap, but trying to outpump a foundation leak is more expensive long-term.

8. The Pit Liner Is Leaking

Older homes sometimes have cracked or damaged sump pit liners that let groundwater flow directly into the pit, even when the ground is not saturated. Looks like normal pump operation until you realize the pit refills quickly even when it has been dry for days. How to fix: Replace the pit liner. This is a bigger job than swapping a pump — consult a plumber or experienced basement waterproofer. Budget $300-$800 for the basin and installation.

Emergency Triage: If Your Pump Is Running Now

If your pump is running right now and you cannot figure out why, here is the fastest path to diagnosis. (If a storm is coming and your pump is struggling, a battery backup sump pump keeps the pit under control if the primary fails or the power goes out.)

• Check the pit level. If water is below the float-activation point and the pump is still running, the float is stuck. Unplug and free it.
• Listen for the check valve. If you hear water rushing back into the pit when the pump pauses, the check valve has failed.
• Feel the motor. If it is very hot, thermal overload is about to trip. Unplug immediately and let it cool.
• Time the cycles. Cycles under 10 seconds point to check valve problems. Cycles over a minute point to pit or discharge issues.

How to Prevent a Pump from Running Constantly

Most of these causes are preventable with basic maintenance:

• Test the pump quarterly. Pour water into the pit, watch it activate, listen for proper cycling.
• Clean the pit annually. Remove debris, sediment, and anything that could jam the float.
• Replace the check valve every 5 years. They wear out silently. A $20 valve prevents thousands in pump damage.
• Verify discharge line integrity every spring. Check for freeze damage, kinks, blockages.
• Replace the pump at 8-10 years. Do not wait for it to fail. See our sump pump lifespan guide.
• Install a high-water alarm. $20-$60, tells you immediately if the pump is losing the fight.

When to Call a Professional

Call a plumber or foundation contractor if:

• You have worked through this list and still cannot identify the cause
• The pump is running constantly in dry weather with no obvious float or check valve issue (points to foundation/drain tile problem)
• You see active water seepage through walls or floor cracks
• The pit liner is visibly damaged or leaking from outside
• You are uncomfortable working around water and electricity

A plumber service call runs $100-$250. A foundation contractor evaluation is typically $150-$400. Both are vastly cheaper than repairing a flooded finished basement.

Frequently Asked Questions

Is it bad if my sump pump runs constantly?

Yes — continuous running shortens pump life dramatically (motors typically last 1–2 years instead of 7–10 with constant duty), spikes your electric bill, and signals an underlying problem like a stuck float, failed check valve, or undersized pump that needs immediate attention.

How long can a sump pump run continuously without burning out?

Most residential sump pumps can run continuously for 6–24 hours during heavy storms before risk of overheating. Pumps without thermal protection may burn out sooner. If yours runs constantly without storms, the issue isn’t water volume — it’s a stuck float, broken check valve, or pit leak.

Why does my sump pump keep running with no water in the pit?

The float switch is almost certainly stuck in the ON position. Unplug the pump, look in the pit for debris or wall contact preventing the float from dropping, and free or replace it. A failed check valve causing water to drain back can also mimic this.

How much does it cost in electricity if a sump pump runs constantly?

A 1/3 HP pump running 24/7 uses roughly 7 kWh/day, which costs $0.85–$2.10 per day depending on local rates ($25–$65/month). Plus you’ll likely need to replace the pump within months, adding another $150–$400.

Should I unplug my sump pump if it won’t stop running?

Only briefly, to inspect the float — and only if water isn’t actively entering the pit. If it’s storming or the pit fills quickly, leave the pump plugged in (a constantly running pump is better than a flooded basement) and call a plumber for emergency replacement.

Related Sump Pump Problems

If your pump is running constantly and also making unusual noises, failing to turn on at times, or cycling erratically, the underlying cause may overlap with other issues. Check our guides on:

• Sump pump not turning on — 9 causes and fixes when the pump fails to activate
• How often should a sump pump run — normal cycling patterns vs. problem patterns
• Do I need a backup sump pump — protection against primary pump failure or power loss

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