Sump Pump Float Switch: Let Us Probe Into The Details Of Each Type

Last updated on April 16th, 2021 | By: Grady Galvez

Overviewing each sump pump float switch types is quintessential whether it is for your existing or new installation. These small devices are potentially used to activate or deactivate alarms, timers, pumps, and more.

sump pump float switch adjustment

Can you imagine!!!

Where flooding is common, millions of the houses world-over have been saved by just a small float switch as they have prevented extensive amounts of destruction.

You should choose the best float switch for sump pump as the full amperage of the pump is carried on by these switches.

So, when you pick a float ensure that the specific pumps amperage is handled by it properly.

(More things to consider prior to purchase….refer below)

This potential element of the drainage system – a float switch, is quite simple to install, as it can be wired directly into the motor-housing, can be plugged into the switch through a piggyback plug or spliced into the power cable.

Four Major Types Of Float Switches

These different types of float switches can be bought along with the pump or separately. One key factor that will dictate your decision of opting a float switch is the diameter of basin.

Note: Before you order for a float, the manufacturer’s recommendations should be checked on minimum basin diameter.

Vertical Action Float Switch

float switch


  • You can use it in tighter spaces as compared to the tethered float

  • Pumping range is adjustable

  • Fairly reliable

  • Easily replaceable (Piggyback Plugs Only)

  • Float travels up/down a fixed vertical rod, so adjustment can be done for few inches only

  • Pumping range is small and may cause pump to rapid-cycle

  • Scum and debris may get caught and annual cleaning needed

Sump Pump vertical float switch is of great quality and available at an affordable price. As the water level will rise, simultaneously the ball will also rise. Later on, when the ball hits the desired level, automatically the switch is activated.

This switch is specially designed for a limited movement only and goes up and down. This feature works as a positive and eliminates its chances of jamming or getting stuck as compared to the others.

Diaphragm Switch

float switch for sump pump


  • Smallest footprint in basin and can be used in the tightest applications

  • Easily replaceable (Piggyback Plugs Only)

  • Not so reliable like the others

  • Hard to clean

  • Pumping range is small and may cause pump to rapid-cycle

  • Pumping range is small and may cause pump to rapid-cycle

  • Scum and debris may get caught and annual cleaning needed

In comparison with others, the diaphragm switches are the most expensive type of sump pump switch. Generally these are used by professionals, are quite sensitive to pressure and submerged underneath.

The working of the switch depends on the water pressure. When the pressure of water increases the switch curves inward and this turns the switch on and when the pressure decreases the switch gets turned off.

Though being a bit high on price this is relied on by many professionals because they don’t get stuck like the others and eliminate any sort of problems.

Tethered Float Switch

pump float switch


  • Most adjustable pumping range

  • Quite Reliable

  • Easily replaceable (Piggyback Plugs Only)

  • For functioning properly needs a large basin (14 inches minimum)

  • Scum and debris may get caught and annual cleaning needed

The tethered float switch is highly preferred by the people who want to do some home projects with the DIY (do-it-yourself) methods.

Designed especially for pedestal sump pumps these floats depend on the height or the level of water. This is possible by a float that hangs-out from the pump.

But these minute problems do not make this a worthless one rather the switch comes with some advantages too. Since it is above the water-level, so your worries about power or electricity are ruled out. As some of these are placed under water and may require frequent invigilation which may occur due to electrical problems.

But some common problems are assisted with this kind of switch when you use them. This may get caught, or end-up sinking, or even fail to begin the sump pump some times. All this may occur due to lack of proper activation.

Electronic Switch

sump float switch


  • This doesn’t float at all

  • Remains submerged in water

  • Quite reliable

  • Depends on water-pressure

  • Easy to install

Often called by the name flood-free switch, this is one of its kind that doesn’t float at all. This remains immerged in water and is completely dependent on the water-pressure for the activation of the probe wire inside.

In case of any issues there is another probe for triggering a back-up.

Selection Criteria

You need to remember this!!

Before you select any one of the above four types, you should always consider benefits and drawbacks in mind.

The next key thing is the location of the pump in your home. You need to check out the comfort of people and the animals living there.

Doing research is the right way to find a genuine and useful float switch that suits your needs.

Expert Tip: If electricity is a worry in your area, then choose accordingly.

Selecting For Existing And New Installations

For Existing Installations

It is easy to swap out if a pump operating via a piggyback plug fails.

Though the replacement will need complete disassembling and motor re-wiring.

Replace it with the same type of pump switch like that of the old.

For New Installations

A pump switch is included in an automatic pump, either wired directly (into the motor) or with a piggyback plug.

It is simple If the basin diameter is 14” or more, opt for a tethered switch. This will offer a long pump life.

If it is less than 14” then a vertical switch is the right one to go for.

Diaphragm switches are made to support unique applications where the tethered or vertical are a misfit.

Functions Controlled By Sump Pump Float Switches

Numerous functions are governed by the Sump Pump Float Switches.

They are designed to manage, makeup water, activate low water cut-off switches, turn on/off high or low-level alarms and more.

1. Control Makeup Water

Firstly, the float switches work to synchronize the water-level in the basin and later manage it to assure that there are normal operating levels. All this is done automatically by the float switches.

2. Low or High-Level Water Alarms

Both types of water alarms, low or high tend to give a warning to its users when there are any incorrect operating levels of water.

The dry contacts get the alerts automatically and LED alarm indicators are lit-up calling for some immediate corrective action warning the system.

submersible pump float switch

3. Low Water Cut-off

This is when the low water-levels are detected then you require a low-water cut-off.

When unattended the pump is shut-off automatically and this helps you increase your savings by eliminating the water pump repairs which could be required frequently.

Digital control systems or pilot duty controls can be used with dry contacts for automatic shut-down of the equipment and this is very important when there are no water or low water circumstances.

4. Digital LED Display

LED indicator lights alert you, warn you, and make you aware at the right time whenever any kind of fixing or reparation is required and immediate turning on/off is needed.

You exactly know where your sump pump water levels are all the time with the digital LED display.

These Float Switches Are Versatile

  • Sump pump Float switch work to detect and actuate the pump from rising water levels.

  • Water tank float switches help to control water level for waste water, rain water, and sewage applications.

  • Air-conditioning and refrigerants also use them for controlling water-levels.

  • Even the industrial washers use them.

Apart from using for a sump pump, these float switches can be used for many residential and industrial applications for notifying the user. Most common uses are:

Sump Pump Float Switch FAQ’S

Q1. How Can I Install A Sump-pump Float Switch?

Ans1. The rise in water levels are detected efficiently by a sump pump float switch. Normally this should be installed in a closed position and when the water will rise the electric circuit will automatically close. These can be wired directly into the motor-housing, can be plugged into the switch through a piggyback plug or spliced into the power cable. This will automatically allow the current to pass for signalling the pump when needed. These are easy to install and can be replaced nearly with any float switch.

Q2. How Does The Float Switch Work?

Ans2. The float switches tend to move with the level of liquid/water up and down. With the gravity the internal mechanism of the switch opens or closes the electrical circuit. Like the water pump the electrical circuit can turn on and off the equipment.

Q3. How Can I Know That My Float Switch Has Turned Bad?

Ans3. First of all, enough water should be filled for raising the float till the pump kicks on. If you see that the pump doesn’t activate when after filling pit the water reaches near to the top. Then this is a case of a bad switch. A float switch in good condition will always lower the level of water by removing the extra liquid.

Q4. Can You Adjust A Sump Pump Float Switch?

Ans4. Here, the model of sump pump and the float switch type decides whether any adjustments that can be brought. However, you can go for some manual adjustments on a rod or tether and the rod settings can be changed by sliding the sump float up/down as per the desired height. And the short tether will need shallow water levels to turn on the pump.