my sump pump runs constantly; for how much longer?

We’ve had a lot of heavy rain here and my house sits quite low. I replaced my sump pump about two years ago. I bought a reasonably good one. My only question is…how much longer can this thing last? It goes on about every 60 seconds!! it’s been doing this for days now and there is more rain predicted for tonight. If this thing quits, I’ll have a mountain of water in my basement. Should I buy a spare and keep it handy? or can I reasonably expect my current one to run for a long long time? even tho it is cycling on and off almost constantly?

It shouldn’t cycle on and off that quickly. Either you’ve got something wrong with your float switch which is causing the pump to short-cycle like that, or you’ve got an ungodly amount of water coming in.

All of that short-cycling and constant pump starting is going to drastically shorten the life of the pump.

well what I notice when I look in the sump pit is that the water only goes up about six inches, then the pump comes on and drains it down about six inches, then it does it again and again. If the pump would allow the sump pit to fill up a foot or two before it kicked on, it would have to run a lot less.

You may need to install a check valve to prevent the water still in the hose that was pumped out from being suctioned back into the pit.

Shouldn’t there be 2 sump pumps, with one set to a higher float switch than the other one? (so it never comes on unless the first one fails)?

How much does the actual sump pump hardware cost, vs the cost of installing all that piping or the cost if your basement floods?

Having had several sump pumps replaced and one installed from scratch, I feel qualified to pass along this comment since all this work was done by professionals.

When I had one aging sump pump replaced, the installer noticed it was sitting too low and put some bricks under it to bring up the level. I know nothing, so my immediate thought was that getting rid of more water is a good thing. This installer told me that when installing a sump pump, you have to be careful not to have it sit too low “otherwise you will be pumping water for the whole neighborhood!”. This sump pump has been in successful operation now for 5 years or so.

Talk to a few experts, having them come out and look over your situation. It might be too low. I don’t know how they determine what’s the current level for a sump pump.

The other thing I did, as a home owner who worries about such things, I bought for $15.00 at Home Depot a water detector for sump pumps. They work on batteries, and you drop the sensor down into the sump pump pit, so if water raises to that level, the alarm goes off. It’s a loud alarm too. I did this so I don’t have to be concerned about checking the sump pump all the time to see if it’s working or needs service.

The second sump pump pit has a constant level of water in it, unless it rains heavy and comes into the pit, then it gets pumped out. But I can tell you, if I go over to it, and shake or thump the PVC connect to it lightly it will forced the sump pump to come on and drain out the water. But the water comes back into the constant level I was referring to immediately. So it appears this sump pump is at the right level, because it doesn’t come on unless there is water above it’s constant level, and the constant level doesn’t seem to present a problem.

I’m not an expert on these things, never worked on them or installed them, this is just information I have gathered from watching the pros and asking them questions. Still I recommend you find the best in the area to look over your situation and someone who has been in business servicing your area for a long time. Because they might be able to tell you the collective experiences of your neighbors and determine what is and isn’t unusual.

One last story, one of the plumbers told me he bought a house where he has two sump pumps running almost constantly. He even has a battery back-up for both of them. He said if the power goes out, his basement would begin to flood after 4 hours.

Yeah, that’s what is called “short cycling” since it cycles on and off for very short times repeatedly.

Do you know what type of switches your pump has?

A tether switch is just a float on the end of the wire. When the water level is low, the float sinks down and the switch is off. When the water level rises, the float rises with it, and slowly rotates as it rises (since the wire holds one end in place, tethered). Once it flips far enough over, the switch turns on and starts the pump. If the wire is caught under the pump, the float can flip up too early and cause short cycling. If the float is bad and doesn’t float right, it may almost immediately flip up on end and cause short cycling.

A vertical switch is basically a float that goes up and down on a rod. I don’t have a lot of experience with these. If the switch got knocked loose and is sitting much lower on the rod than it should be then I could see that causing a short cycle.

A diaphragm switch is usually mounted at the bottom of the pump or maybe sometimes just at the bottom of the pit. As the water rises, the water pressure pushes against the diaphragm. Eventually the pressure pushes hard enough to activate the switch. If the diaphragm is worn out, it will cause the pump to short cycle.

So the first thing you need to do is figure out what type of switch you have.

You may have more than one switch, with the second serving as a backup in case the first switch fails.


Diagram of a tether switch:

Vertical switch:

Diaphragm switch:

Take a picture and we can offer better advice.

Yes a single phase motor will experience a much shorter life turning on and off like that.

Reasons it may do so

  1. Check valve is failing so it pumps water out the discharge pipe and that same water flows back through the discharge pipe and needs to pumped out again.

  2. Float is poorly set or adjusted. The float should be set to maximize run time, turning on when the pit is just about full and turning off when it is just about empty.

  3. Sump pit is of insufficient size. Many times people install too large a pump in too small a sump pit. You want to pit to be able to hold 15 or more gallons.

I was thinking faulty check valve.
When the pump pumps down the sump and turns off. unplug the pump and watch the water level. If the level comes up to the point of closing the float switch and stop raising, then you have a faulty check valve. If the level keeps raising above the switch level then you have a lot of water coming in and I would consider modifying to a two pump sump. Also if you can adjust the floats I would. Increase the difference between turn on and turn off.

A quick check of Home Depot says that an inexpensive sump pump is $130. The expensive ones are $400-$500 and have battery backups.

It would make sense to have a parallel system. Engineer comp geek, you remember the section on reliability in your textbooks? Where it shows how a parallel system boosts reliability far more than using a more expensive component that is a few percent better?

Not only do I remember my textbook training, but I was also trained using Air Force and Navy training materials on how to do reliability analysis while I worked for a defense contractor many years ago, and for the past couple of decades I have worked for a company designing fully redundant, high reliability industrial controls. So yeah, I have a little bit of a familiarity with reliability concepts. :wink:

You have to be careful setting up something like redundant sump pumps. Depending on how they get triggered, one can end up doing the bulk of the work while the other ends up short cycling and wears itself out early.

We actually had a similar problem with two of the air conditioning units in the building where I work. One was doing the bulk of the work in the area that the two shared, and the other ended up short cycling as a result.

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The sump hole collects water from around the foundation of the building. If the drain tile, or drain system pipe, breaks, the sump hole may also fill with dirt and clay. If a sump pump sits too low in the hole, it may become clogged with muck. While some sump pumps have legs to avoid this, you can still place bricks under the pump, but not blocking the intake, to allow the pump to push water up and out.

I recently replaced a sump pump that seemed to never stop running. I listened to it run frequently for longer than I should have. (Once I actually looked into the pit, I felt like :smack:ing myself.) The pump was leaking furiously from a split where the 2 halves of the pump were gasketted together. It was pumping the same water over and over again.

Mine was cycling about the same amount and died after 5 years ( It was the original with the house). One of the problems I had was short cycling due to the water running back into the pit through the flex hose.
Once I replaced the pump, I also replaced the flex line with 1.5" abs and a check valve. It now runs less than a third as often.