How do I fix a stuck sump pump float switch?

The short answer

A stuck float is usually not a broken float. Something is holding it down or pinning it in place: the pump has shifted or tipped, the power cord or discharge pipe sits in its path, the float rubs the pit wall, or silt has built up on it. Unplug the pump, set it upright, clear the float's path, tie the cord out of the way and test it with a bucket of water. If the float moves freely and the pump still will not start, the switch has failed and needs replacing.

Unplug before you touch anything

Sump pumps sit in water and run on household current, so the order matters. Wayne's manual says to always disconnect the pump from the power supply before servicing it or making any adjustments, and to never handle a pump with wet hands or while standing on a wet or damp floor while it is plugged in.^[1] FEMA's flood guidance makes the same point for any equipment: "Do not touch electrical equipment if it is wet or if you are standing in water."^[3]

If the basement has already taken on water, do not walk on the floor when water is present until all power is turned off, and if the electric panel is in the basement, call an electrician.^[1] Then give the pump time: Wayne says to let the pump cool for a minimum of 2 hours before servicing it, because the oil inside becomes pressurized and hot in normal use.^[1]

Most residential pumps plug in. Some have a separate float switch with its own "piggyback" plug that the pump's plug pushes into, so pull both. If your pump is wired straight into a junction box with no plug, stop here: that is an electrician's job.

Why floats get stuck

The pump moved or tipped. Wayne warns that vibration during operation can make a pump fall or tilt onto one side, which can jam the float so it cannot start the pump.^[1] It also says rigid piping is required to hold the pump in place, because pump movement can stop the switch from working correctly, and flexible hose should not be used.^[1] If your pump hangs from a flexible hose, that is often the root cause.

The float touches the pit wall. Wayne's installation steps call for at least 1 in. of clearance to the side wall of the basin and say to position the pump so the switch is away from the inlet, clear of incoming water.^[1] A pump that has drifted a few inches can put the float against the wall or under the inlet pipe.

A cord is in the way. Wayne says to secure the power cord to the discharge pipe with cable or zip ties to prevent the switch getting tangled.^[1] A loose loop of cord can settle on a tether float or wrap around a vertical float's rod.

Silt and debris. Sediment from drain tile settles in the pit, and minerals and grime build up on the float and its guide rod over time. A float that drags on a dirty rod may rise late or not at all.

Know which float you have

A vertical float rides up and down a rod or inside a small cage beside the pump, like the white ball in the photo above. A tether float hangs on a short cord and swings up as water rises. They switch on at different heights. On its vertical-float pumps the factory-set on level is approximately 9 in. and the off level approximately 4 in., and on its tether models approximately 13 in. and 7 in.^[1] Those are Wayne's figures; your manual has your pump's.

Do not "fix" a stuck float by bending its rod or shortening its tether. Wayne says its tether float is not adjustable, and that changing it can affect how the pump performs and how long it lasts.^[1]

Test it properly

After clearing the float, plug the pump back into its GFCI outlet and pour water into the pit until the pump starts. It should stop on its own once the water drops to the off level. Fill and drain it a few more times and watch the float the whole way: it should never touch the pump body, the discharge pipe, the cords or the pit. For more on testing, see how to test a sump pump.

If you have a battery backup pump with an alarm, a sounding alarm is a clue too. Goulds' backup manual says that if the alarm sounds, check operation of the primary pump, which may need service.^[2]

When the switch itself has failed

If the float moves freely, the pit has enough water and the outlet works, but the pump still will not start, the switch has probably failed. In Wayne's troubleshooting chart, the remedy for a failed switch is to replace the tether switch or replace the pump.^[1] Wayne sells a float kit, a vertical float switch kit and a tether switch as repair parts,^[1] and other makers sell their own; match the part to your pump's model number.

Switches also wear out on a schedule. Wayne requires replacing its tether switch every two years,^[1] and says to inspect the pump 3-4 times per year for movement or debris building up on the switch or float.^[1] If yours is older than that, replacing the switch is cheaper than a flooded basement. If the switch is built into the pump body and cannot be swapped, the fix is a new pump; see how to replace a sump pump.

Stop and call a pro if

• The pump or its switch is hardwired into a junction box rather than plugged into an outlet.
• The outlet is out of reach. If the receptacle is not within reach of the pump's cord, Wayne says to have a qualified licensed electrician install a new one rather than use an extension cord or surge protector.^[1]
• The GFCI outlet trips again as soon as you reset it, or the cord is cracked or damaged.
• There is standing water on the floor and the electric panel is in the basement.
• The pump hums but moves no water, runs constantly, or vibrates loudly. See why a sump pump runs constantly and why a sump pump won't turn on.
• A new switch does not fix it, or rain is coming and you cannot get the pump working.

A plumber can swap a switch or a pump in one visit. Browse plumbing repair answers, see sump pump repair on Loclis, or find licensed plumbers near Blacksburg. When you are ready, describe the job once and get quotes from licensed plumbers.