Why Does My Sump Pump Keep Running? 5 Common Causes

Why Does My Sump Pump Keep Running?

A sump pump that runs constantly usually points to one of five things: a stuck or misadjusted float switch, a missing or failed check valve letting water flow back into the pit, a pump undersized for the water volume, a pit that is too small for the incoming flow, or an actual groundwater problem that has changed around your foundation.

None of those fix themselves, and a pump running around the clock is burning through a motor rated for intermittent duty. The failure is coming; the only question is whether it arrives during a dry week or during the storm you needed it for.

Here is how to diagnose it, when it is a DIY item, and when to call.

How a Sump Pump System Actually Works

Understanding the parts makes the diagnosis obvious:

• The sump pit (or basin) is the low point that collects groundwater from drain tile around the foundation.
• The pump sits in the pit and moves water out.
• The float switch senses the water level and tells the pump when to start and stop.
• The check valve sits in the discharge line and prevents water in that pipe from draining back into the pit when the pump shuts off.
• The discharge line carries water away from the foundation.

Two main designs dominate: pedestal pumps, which sit above the water line with the motor exposed, and submersible pumps, which sit down in the water. Pedestal units are cheaper and easier to service; submersibles are quieter, handle more debris, and generally move more water.

Worth understanding before you diagnose anything: a sump pump manages groundwater, not sewage. If what is coming up in your basement is not clean groundwater, you have a drain or septic problem, not a sump pump problem. The EPA's SepticSmart homeowner resources cover that distinction for homes on onsite systems.

The Five Reasons Your Sump Pump Runs Constantly

1. Float switch problems

This is the most common cause and the easiest to check. The float can get hung up on the pit wall, the pump body, or the discharge pipe. If the float cannot drop, the pump never gets the signal to stop. Look in the pit — if the float is physically caught on something, that is your answer.

Float switches also fail electrically. A tethered float with a worn switch can stick closed, which means the pump runs regardless of water level.

2. Missing or failed check valve

Without a working check valve, every time the pump shuts off, the column of water sitting in the discharge pipe drains straight back into the pit. The pump reads a high level, kicks on, pushes the same water up again, shuts off, and the water comes back down. This creates a short-cycling loop that will destroy the motor. If your pump runs in rapid on-off bursts, check the valve first.

3. Undersized pump

If the pump cannot keep up with the inflow, it never gets the pit low enough to shut off. Common after a finished basement project, a change in site grading, or a new neighboring development that altered how water moves across the area.

4. Pit too small

A pit with too little volume causes rapid cycling because a small amount of inflow crosses the on-threshold quickly. The pump is fine; the basin is wrong.

5. Genuinely high groundwater

Sometimes the pump is doing exactly what it should, and the real story is a high water table, a broken water line nearby, or drainage that has changed. This is worth knowing rather than assuming — if a supply line is leaking underground, a leak repair is the actual fix and the sump pump is just the symptom.

Sump Pump Maintenance Checklist

Quarterly, and definitely before spring:

• Pour a bucket of water into the pit. The pump should start promptly, clear the pit, and stop cleanly. This single test catches most problems.
• Check the float for obstructions. Make sure it moves through its full range freely.
• Clean the inlet screen. Debris restricts flow and makes the pump work harder.
• Verify the discharge line is clear and, in winter, not frozen. A frozen discharge line means the pump runs against a closed pipe.
• Confirm discharge terminates well away from the foundation. Water dumped next to the house comes right back to the pit.
• Test the check valve. Listen for backflow after shutoff.
• Confirm the outlet is a dedicated GFCI circuit and that nothing has tripped.

That last one matters more than people expect. A tripped breaker or GFCI is a silent failure — the pump looks fine and does nothing.

Do You Need a Battery Backup?

Consider that the storms that produce the most groundwater are the same storms that knock out power. A sump pump without a backup is a device that reliably fails at precisely the moment you need it.

Options include a battery backup pump, which is a secondary pump on a deep-cycle battery, and a water-powered backup that runs off municipal water pressure with no electricity at all. Water-powered units are not an option on a well, since well pumps also need power.

If your basement is finished, a backup is not a luxury. Flood damage documentation and recovery guidance from Ready.gov's flood preparedness resources is worth reading before you need it, and the FEMA FloodSmart program covers what standard homeowners insurance does and does not cover for flooding — a distinction that catches a lot of people off guard. The short version: standard homeowners policies generally do not cover flooding, and the definition of "flood" versus "water damage" is where claims get decided.

We work with insurance companies regularly, and the single biggest factor in how a water claim goes is documentation of the source. If your pump has failed and water is in the basement, photograph everything before you start cleaning.

When to Repair vs. Replace

Sump pumps generally last 7 to 10 years. Replace rather than repair when:

• The pump is past 10 years, regardless of current condition
• The motor is seized or the pump runs but does not move water
• You are seeing repeated failures
• The pump has been short-cycling for a long time — that motor has lived a hard life
• It is undersized for the actual water load

Repair makes sense for float switches, check valves, and discharge line issues on an otherwise healthy pump. Our sump pump service covers both, and we have done hundreds of installs and repairs in the area.

Sizing the replacement correctly

Pumps are rated in gallons per hour at a given lift height, and that second number is what gets ignored. A pump rated for 3,000 GPH at 0 feet of lift might only move half that at the 10-foot lift your actual installation requires. If your current pump has never quite kept up, replacing it with the same horsepower reproduces the same problem. We size to the real lift and the real inflow.

Discharge line diameter matters too — a strong pump pushing through an undersized or partially blocked line is doing work it does not get credit for. That shows up as a pump that runs a long time to clear a pit that should empty quickly.

Sump Pump Service in Culpeper

We serve Culpeper and Culpeper County along with the broader region between Stafford and Richmond. If your pump is cycling oddly or you want it checked before the next big rain, that is a short visit that prevents a long weekend.

One client of ours had his sump pump diagnosed in ten minutes and a new one installed and running twenty minutes after that. That is the goal — sump pumps are not complicated, and the problem should not take three visits to identify.

We also handle the systems that connect to it. If persistent groundwater turns out to be a failing supply line, that is a plumbing repair. If your home is on septic and saturated ground is coming from a drainfield rather than the water table, that is a septic repair. Those are genuinely different problems with the same symptom, and telling them apart is most of the value of the visit. You can see everything we cover on our services page.

Frequently Asked Questions

How long should a sump pump last?

Seven to ten years is typical, though a pump that has been short-cycling due to a bad check valve can burn out in a fraction of that. If yours is over a decade old and still original, plan on replacement rather than waiting for it to prove the point during a storm.

Is it normal for a sump pump to run every few minutes?

Not usually. During heavy sustained rain it can be legitimate. In dry weather, running every few minutes almost always means a failed check valve is letting discharge water return to the pit, or the float is stuck. Both are quick fixes and both destroy pumps if left alone.

Do I need a backup sump pump?

If your basement is finished, stores anything valuable, or has ever taken on water, yes. Power outages and heavy rain arrive together, which means a primary pump on house current is unavailable exactly when the water is worst. Battery backups are the common choice.

Why is my sump pump running but not pumping water?

Usually a clogged inlet screen, a stuck check valve, an air-locked impeller, or a discharge line that is blocked or frozen. If the motor hums but nothing moves, shut it off — running a pump against a blockage cooks the motor quickly.

Can I install a sump pump myself?

Swapping a like-for-like pump in an existing pit is within reach for a confident homeowner. A new installation is not — it involves pit excavation, discharge routing, electrical work, and sizing decisions that determine whether the system actually protects your basement. Getting discharge routing wrong recirculates water right back to the pit.

How far should the sump discharge be from the house?

Generally at least ten feet, terminating where the grade carries water away rather than back. Discharging next to the foundation is one of the most common installation mistakes we correct, and it creates a loop where the pump keeps pumping the same water forever.

Get It Checked Before the Next Storm

A sump pump inspection takes a few minutes and tells you whether you are protected. Get a quote or call (540) 645-1351.