My Sump Pump Float Is Stuck (Repair Guide)

Having the sump pump float is stuck would usually be the main reason that your sump pump will not turn on. The floating element should have enough room to move freely without debris in the way. So, here is a quick guide on how to fix your float switch to restore the function of your sump pump.

sump pump float is stuck

How Does a Sump Pump Float Switch Work?

A float switch is a type of sensor that detects the rise in water levels and activates the sump pump to start removing water. The most commonly used type is the tethered float switch. Vertical switches, diaphragm switches, and electronic switches are also commonly used in sump pumps. Similar to the activation of the sump pump, the float switch can also detect it when the water levels fall and will turn off the sump pump. The float switch usually connects directly with the pump in the mechanism.

Types of Float Switches

There are a few types of float switches used in sump pumps. The main difference is in the mechanism of the switch used in detecting the water level. Most switches use mechanical ways to find the presence of water, while new switches use electrical circuits.

Tethered Float Switch

In tethered float switches, a hollow body floats with a steel ball inside and is attached to the pump with a cord. The ball inside moves when the float pivots and turns on an electrical switch. The level range of the switch can be determined by changing the length of the cord. Despite being a simple and reliable process, the downside of tethered float switches is that they need a large basin for the float to move. As the cord length increases, there is a higher risk for the float to get tangled inside the basin.

Vertical Float Switch

Vertical switches have a simple design with a floating element connected to a switch through a rod. These are mainly used in smaller basins with low depths and a small level range. It only takes space for the length of the rod. As the floating element raises along with the water level, the rod pushes a lever that turns on the electric switch. Certain other designs have a floating element that can slide over the rod. The float contains a permanent magnet that operates reed switches when it crosses predefined points in the rod. Vertical float switches can be more accurate than tethered switches.

Diaphragm Float Switch

This type of float switch has a diaphragm that deflects under water pressure. This happens as the pressure increases with the rise in water level. Then the diaphragm deflects and operates the switch that turns on the sump pump. 

Electronic Switch

More electronic switches are introduced to the market with the development in technology. These switches are more reliable compared to all the other types of float switches. A small current is applied to the probes, and when they submerge in water, an electric circuit is created, allowing the current to flow. The sensor measures the electrical resistance, compares it with preset values, and detects the presence of water. It will then transmit the signal to turn on the sump pump.

Why Does a Sump Pump Float Switch Fail?

The different types of float switches have different reasons for failure. The most common reason behind float switch failure is the floating element getting tangled in the basin. It can get stuck between the pump and the basin wall. This causes the malfunction of the float switch as it cannot raise or drop with the water level. This can be fixed easily once you locate the floating element. 

Rusted/ Damaged Floats

Corrosion is a problem in most float switches over time. Although most floats are resistant to corrosion, they get damaged when used for extended periods. The hollow float switches are the ones that often get punctured. This may damage the floating element beyond repair and so you need to replace it with a new one.

Debris in Sump Pit

A dirty sump pit with a lot of debris can be a leading cause of float switch failure. The motor cannot turn on at the needed time if the system has a sump pump float switch stuck on debris. Always make sure to keep the sump pump clean and prevent any objects from falling into the pit. A defective float switch can lead to activation problems in the sump pump causing basement floods.

How Do You Adjust a Sump Pump Float Switch?

If you find the sump pump float is stuck inside, you can recover it easily by cleaning the element. Here are the steps through which you can repair the float switch inside the basin.

  1. Disconnect the sump pump from the power supply and the plumbing lines. Wipe away any debris on the unit and remove the sump pump from the basin.
  2. Remove any grime stuck on the sump pump using a high-pressure hose. Clean the floating element as grime stuck on it can cause it to malfunction. Wipe off the excess moisture with a dry towel and replace the element.
  3. Connect the parts as you found them and plug the sump pump into power. 
  4. Test the sump pump by adding some water to the basin. If it still doesn’t start, you may have to try replacing the float switch.

How to Replace a Sump Pump Float Switch

If you find that your float switch is faulty, despite cleaning it, you may need to replace it. Follow these steps to replace a new float switch in your sump pump.

  1. Unplug the sump pump from the power outlet and disconnect it from the drainage line. 
  2. Unscrew the sump pump float cap using a screwdriver. You might have to look up the user manual since the mechanism varies with manufacturers and sump pump models.
  3. Note down how the wires inside the sump pump cap are connected. It comes in handy as you reconnect the new switch. 
  4. Then disconnect the wiring to the float switch and unscrew the float switch from the cap. Keep the screws safe in case the new float switch doesn’t come with screws.
  5. Place the new float switch in the correct position and fix it with screws.
  6. Connect the wires with the help of your notes or diagrams taken down previously as you disconnected them.
  7. Screw the float cap back on the sump pump and place it in the sump basin. Connect the power supply and the plumbing lines disconnected previously.

Frequently Asked Questions

How Do I Know if My Sump Pump Float Switch is Bad?

You can test the float switch by filling the sump pit with water so that the floating element raises and turns on the sump pump. If not, you can raise the switch by hand until it turns on the motor. If the pump doesn’t activate, even with the suitable height of the switch, the switch might be bad.

You can test the sump pump float switch using a multimeter. Set the multimeter to the Ohms and place the probes on the float switch wires. It should read zero when the float is in the down position, and the reading needs to change to one as you lift the float. If the readings do not change with the height as mentioned, the float switch is probably defective.

How Much Does It Cost to Replace a Sump Pump Float Switch?

The average cost of replacing a sump pump float switch is between $100 and $150. This is usually a simple task that can be done easily with minimum effort. Since the sump pump float switches are easy to install, labor costs wouldn’t be that expensive.

How Long Do Float Switches Last?

The average useful life of a float switch is usually around 2 – 3 years. After that, the floating elements tend to give various signs of malfunctioning. This happens as the float switches move up and down in the water for a long time. But this will not be a major issue as the float switches are relatively cheap and can be replaced easily.

Is Standing Water in Sump Pump Normal?

Having some water inside the sump pit is a normal situation. It happens due to rain or water seeping in from the ground. When this water level rises to a certain level, it should trigger the sump pump float switch which will in turn activate the pump to start working. 

Do Sump Pumps Require Maintenance?

Just as with any other appliance at home, a sump pump also needs regular maintenance to keep it functioning properly. You should inspect the sump pit regularly to make sure that is clean, and the float switch can function well. Cleaning the drainage lines and testing the sump pump occasionally is also important.


It is always a good precaution to check your float before a major storm or heavy rainfall. It will prevent your basement from flooding and save your property from water damage costing thousands of dollars. Always keep the sump pit clean and make sure nothing can slip and fall inside. If your sump pump is old and prone to possible faults, you can have a backup sump pump to eliminate the risk.

Related Resources