Why is Sump Pump Turning On and Off? Causes and Solutions

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After buying a sump pump, a lot of people tend to forget that the pump exists. However, you would be wise to pay attention because it is the ultimate savior of the basement. When it runs for the first time, you have to check its cycling. You need to be on your guard against short or continuous cycling. This apparently small malfunction can turn into a huge disaster if not taken care of.

There are particular reasons why the machine keeps turning on and off even buying it after keen inspections, and these are:

  • The pump basin is too small for heavy rain.
  • It might have a vertical float switch rather than a tethered one.
  • There might be something wrong with the float switch.
  • Water is flowing back into the pit.
  • Excess water might be flowing into the basin.

Before we dive into the explanation, you have to know a pump’s normal running time. Running for 10 to 15 seconds every cycle is absolutely fine, but the period of every 3 minutes is still acceptable during a rainstorm. However, as you scan through the article, you will get to know the reasons behind the irregularity in its cycle and the solutions.

Why is Sump Pump Turning On and Off

What is short cycling?

If your basement holds standing water, it is natural for the machine to kick on two or three times a day. There is nothing to worry about until there is a short cycle, the symptom of a problem. Now, let us introduce you to what this term refers to. Short cycling means that a pump will inconsistently stop working even when there is standing water in your pit. It can happen for the reasons mentioned above. If it keeps happening over and over, it cannot remove water entirely from the basin, and ultimately the basement gets flooded, causing all sorts of damage.

Why is Sump Pump Turning on and Off-

Here is a neat little list of causes and solutions to help you overcome this problem.

Problem – 1: A small basin

During heavy rain, a small basin is inadequate to hold a large volume of water; Therefore, it gets full quickly, and before driving out enough water, it gets filled again. This imbalance between the capacity and incoming volume of water causes the pump to malfunction.

Solution – 1: Use of a larger pit

If it is a sump pump of ½ or 1/3 HP, then during waterflood, the small basin will fail to keep up with the quick rise of water and fill up instantly. Therefore, a larger basin will shorten the cycle.

Problem – 2: A vertical or float switch?

Knowing the differences between a float and vertical switch for the pump to work efficiently is necessary. If a vertical one is used instead of a horizontal one or vice versa, it will keep on turning on and off.

Solution – 2: Use of appropriate switches

If the sump pit is really deep and has a wider diameter, it is better to use a tethered switch as it will take time for the water level to reach the switch, extending each cycle. Therefore, the device will take time to shut, allowing the motor to cool down for a while.

Problem – 3: Improper positioning of the float switch

Even after having the appropriate float switch, there might be something wrong with the switch if the problem is still unsolved. Due to a wrong positioning, the cycling period is disturbed.

Solution – 3: Adjust the float switch

Open the pump and check whether the float switch is in position or somehow broken. If it is not in place, adjust it. Fixing it with the help of a manual is easier than waiting for a plumber. You have no other option than to buy another one if the existing switch is unfixable.

Problem – 4: Problem with the check valve

Another reason that can be shortening the cycle is the backflow of water into the pit. The check valve is responsible for ensuring water flow in a forward direction. If it is broken, there is a high chance that the hole is getting full again.

Solution – 4: Repair the check valve

The float switch is alright and the pit is of absolute size; if the pump is still short cycling, you have to go for the check valve. Repair it or replace it; otherwise, the device will have a hard time tackling the flow of water.

Problem – 5: Entrance of too much water

If you stay in a flood-prone area and have a huge house, then your sump pump of less HP will cause you serious trouble. Though the smaller pump with a weaker motor is cheap, you should not buy it. It will keep on turning on and off as more water will enter the pit than being driven out.

Solution -5: Use of powerful motor

The pump of 3/4 HP will be the perfect choice to remove water quickly. You can even buy a backup sump pump if you cannot replace the present primary pump with less horsepower.

Why does it keep on running?

Sometimes, the sum pump constantly running without turning off. If this continues even after the pit dries out entirely, it will explode. This nonstop operation is severe than the short cycling. While the matter of short cycling can be handled slowly, constant running pumps need immediate attention. This problem initiates when the float switch gets stuck in its ‘on’ position or the discharge pipe gets clogged.

To solve the float switch issue, at first, you have to unscrew the device and check if it is entangled upwards. Untangle it so that it moves freely as the water level rises and drops. If it is unrepairable, then you have to replace the switch with the new one. Discharge pipes can easily get clogged due to the pump’s poor filtration system. Therefore, water keeps moving in without any way out, resulting in its continuous running.

What you have to do is detach it from the pump and clean it properly, ensuring the removal of every single piece of debris. Then you can reattach it and use the pump again.


This short cycling and nonstop running are serious problems to address because running every 30 seconds for more than 2 to 3 days will overheat the pump. This overheating may result in a sudden explosion and even start a fire. Therefore, as a precaution, it is important to observe the run-time and act accordingly. We hope that with this information you can tackle the problem of the sump pump turning on and off without having to hire a plumber!

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