Why Does My Sump Pump Run Constantly?

The reason the answer splits three ways is that a sump pump has no judgment. It runs when a float rises, and a float rises whether the water underneath it came from a March thaw, from the pipe the pump just emptied, or from nowhere at all because the float is wedged against the crock wall. Sorting those apart takes about five minutes in the basement, and it decides whether you need a $15 part, a grading correction or real drainage work. Our sump pump installation page covers the hardware side; this page is the diagnosis.

Is it normal for a sump pump to run constantly?

Sometimes, and the calendar usually settles it. In the Chicago area a pump that cycles hard during a heavy rain and keeps working for a day or two afterward is behaving exactly as designed. A pump that runs steadily through the second half of March, while the frost is coming out of the ground and every yard in the subdivision is soft, is also normal. What is not normal is a pump running through a dry August week, restarting seconds after it shuts off, or roaring away over a crock that is nearly empty.

So watch the interval before you diagnose anything. Time the run, then time the silence. Long runs with long quiet gaps mean the pit is filling from outside and the pump is winning. Short runs on a fast repeat, where the pump barely rests, almost always mean the water it just pushed out is coming back down the pipe. That distinction is the whole game.

Why does groundwater keep arriving days after the rain stops?

Because the ground here does not drain, it stores. Northern Illinois sits on dense glacial clay that takes water in grudgingly and gives it up just as slowly. What falls on your yard does not disappear into the subsoil; much of it works down through the disturbed backfill along the foundation, the loosest material anywhere near your house, and pools at the footing where the drain tile and the pit are waiting. That reservoir can take days to draw down, so the pump keeps working long after the driveway is dry. In a spring thaw it is worse, because frozen ground sheds meltwater sideways instead of absorbing any of it.

Two local factors stretch it further. Older neighborhoods drain their footings through clay tile installed when the house was built, and once that tile silts partway shut, water reaches the pit in a slow trickle instead of a quick surge. The pit then runs at a low, steady rate for a week. Newer subdivisions built on former farm fields sit low with a naturally high water table, and their pits are designed to run often. If you have a pump and no perimeter drainage, the picture is different again, which we sort out in whether you still need drain tile if you already have a sump pump.

What makes a pump run when there is nothing to pump?

When the pit is not actually filling from outside, the cause is nearly always on this list. Work down it in order; the cheap items sit at the top for a reason.

• A missing or failed check valve. The column of water standing in the discharge pipe drops back into the pit the moment the pump shuts off, refills it, and starts the pump again. This is the most common cause of a pump that restarts every few seconds.
• A discharge that ends too close to the house. Water pushed out four feet from the foundation soaks straight back down the backfill and returns to the pit, so the pump spends the day bailing the same gallons.
• A float tangled or pinned. A tethered float that catches on the pump body, the pipe or the crock wall never drops far enough to shut the switch off. The pump runs dry, which is also how pumps burn out.
• A pit that is too small or too shallow. A narrow crock holds so little water that the float trips constantly during ordinary inflow, which is common where a previous owner cut in a pit rather than installing a system.
• A blocked or frozen discharge. If the water cannot leave, the pump runs while the pit stays full. In January this shows up as a pump straining against nothing, and we cover the winter version in why a sump discharge freezes.
• Water arriving from something other than rain. A condensate line, a leaking water service, a neighbor’s new discharge aimed at your lot line or an irrigation head running at 5 a.m. all fill your pit on their own schedule.

Here is what each of those actually costs to correct, using our published ranges.

What you observe	What it usually means	Who fixes it
Restarts within seconds, over and over	Water falling back down the discharge	You, with a check valve, or us in an hour
Runs long, rests long, only after storms	Real groundwater at the footing	Nobody yet, unless it is losing the race
Runs with the pit nearly empty	Stuck float or an airlocked pump	You, usually free
Runs hard through dry weeks all summer	A leak or a foreign water source	A plumber, after you check the meter
Runs while water still rises in the pit	Blocked discharge or an undersized pump	Us, same visit
Water also comes up the floor drain	Sewer surcharge, not groundwater	A plumber, plus a backflow device

What does constant running look like in your kind of house?

The same symptom has a different cause depending on when your foundation went in the ground.

Pre-war bungalows and two-flats

These pits sit at the bottom of a deep basement, which means a tall column of water in the discharge pipe and a long lift for the pump. Miss a check valve here and the pump short cycles relentlessly, because gravity hands the water back every time. The other bungalow pattern is a pit fed by tired clay tile: instead of a hard surge during the storm, the pit takes a thin steady drip for a week.

Post-war block ranches

Hollow concrete block is a reservoir with a foundation’s job. Water in the cores travels down through the wall and surfaces along the cove line at the base of it, and it keeps surfacing for days after the storm because the wall itself is still draining. If the walls are also damp to the touch or showing white powder, the water is inside the block, not just under the slab.

1980s and 90s poured walls

Homes from this era usually have functioning perimeter drainage, so a pump that suddenly runs constantly reflects a change in what reaches that drainage, not a failure of it. Most often it is roof water. Grading settles in the first decade or two, downspouts get shortened during landscaping, and an average roof sheds an enormous volume into a small strip beside the wall. Our guide on how far downspouts should extend is the cheapest thing you can read this week.

Newer subdivision homes

In subdivisions built on farm ground, a pump that runs every ten minutes for days is often the design working, not failing. These lots sit low, the water table is high, and the sump is the intended outlet. The real question in these houses is duty cycle: a builder-grade pump running that hard wears out years earlier than the same pump in a dry house, so the useful reading here is how long sump pumps actually last and whether yours is due.

What can you fix yourself, and when is it not our problem?

Plenty of constant-running calls end with us telling homeowners to keep their checkbook closed. These are the honest ones.

It is March and everything is running. During a thaw half the pits in the county are working overtime and there is nothing to fix. Confirm the water stays below the slab and the discharge is clear of ice, then leave it alone.

The check valve is a homeowner job. If the pump restarts a few seconds after every shutoff, unplug it, look at the discharge pipe, and see whether a check valve is installed above the pump. Adding or replacing one is a hardware store errand for most people, and it can eliminate the symptom entirely for less than the cost of dinner.

The pump is running in a dry spell. Before you call anybody about drainage, shut the water off at the house valve and watch the meter. If it is still turning, you have a leak in the service line or under the slab, and the water in your pit is your own. That is a plumber’s job, not a waterproofing job, and finding it that way costs nothing.

The water is coming up the floor drain too. Then the pit is not your main story. Water surfacing at a floor drain during storms points to the sewer, common in the older suburbs on combined systems, and our equipment does not touch that problem. Read why water comes up through a floor drain and start with a plumber.

It becomes our problem when the water is real, constant and winning: a pit filling faster than the pump empties it, or a pump stuck on because the drainage feeding it is silted and slow.

What should you do next?

First, spend five free minutes with a stopwatch. Record the run time and the rest time across four or five cycles, and write down the weather. A pump that runs 15 seconds and rests 8 seconds is telling a completely different story than one that runs a minute and rests twenty, and you now have the number that settles it.

Second, walk the discharge line outside. Find where it exits and where it ends. If it dumps within a few feet of the foundation, extend it and watch what happens over the next week. Also confirm the outlet is legal for your village, since municipalities differ on where sump water may go and a few restrict certain routes outright: where a sump pump can legally discharge in Illinois covers the general rules, and your village is the final word.

Third, have somebody measure the inflow instead of guessing at it. We will time the pit, check the valve, the float, the lift and the discharge, and tell you plainly whether this is a $20 part or a drainage problem. Book the free pit inspection and we will be out within 48 hours, or call (630) 335-1128 if the pump has been running nonstop for more than a day and you want it looked at before it quits.

Questions homeowners ask about a pump that will not shut off

Why does my sump pump run when it has not rained in weeks?

Three usual answers. The water table under your lot may simply sit high, which is common on low subdivision ground and near creeks and detention basins. Something in the house may be feeding the pit, most often an air conditioner condensate line or a water softener discharge. Or you have a leak, which the meter test will confirm in two minutes. Rule out the leak first, because it is the only one of the three that gets more expensive while you wait.

Should there always be water sitting in the sump pit?

A few inches in the bottom is normal and harmless, since the pump shuts off before it runs the crock completely dry. A pit that is bone dry year round means groundwater is not reaching it, which is fine on high ground and worth a look on low ground. A pit that never drops below the halfway mark, on the other hand, means the pump is barely keeping up or shutting off too early, and that is worth a service call.

Is it safe to unplug the pump to stop the noise?

Only long enough to inspect it, and only if you stay in the basement while it is unplugged. A pit filling from outside can put water over the slab surprisingly fast, and the mistake we see most is somebody unplugging a noisy pump at bedtime and finding the floor wet at breakfast. If the noise is grinding or rattling rather than the normal cycling hum, that is a mechanical complaint worth a call rather than a plug you pull.

Does a constantly running sump pump raise my electric bill?

Measurably, but not dramatically. A residential sump motor draws far less than a furnace or a central air compressor, so even weeks of hard running usually reads as a small bump rather than a shock. The expensive part is not the electricity, it is the wear: a pump cycling every few minutes ages on fast forward, and the replacement, not the utility bill, is what constant running eventually costs you.

A pump that never rests is either a symptom you can fix for pocket change or a warning you get one chance to act on. We will time the pit and diagnose it free within 48 hours, price any real fix inside our published ranges, and back the work in writing: 5-year warranty on drainage work, and a lifetime, fully transferable warranty on the interior systems we install. Call (630) 335-1128.