Search guides

Fix a sump pump that will not shut off

We'll check the float and switch—then fix the cause or tell you when to call a pro.

Troubleshooting · Home plumbing
15–45 min
What you'll need
  • Replacement float switch (if faulty)
Step 1 of 7

Quick triage — pick your path

Get started

Choose the option that matches what you see. You can jump straight to that section.

Show full guide

Steps

Goal: Confirm the symptom, check the float and switch—then fix the cause.

  • Look into the sump pit. If the pump runs when the pit is empty or nearly empty and does not shut off, the pump is stuck on.
  • Good: Pump runs when pit is empty and does not shut off. Proceed to Check float.
  • Bad: Pump shuts off when pit is empty—normal operation.

Check float

Goal: Confirm the float switch shuts off the pump when the water level drops.

  • Locate the float switch (a ball or cylinder attached to the pump or discharge pipe). Check that it moves freely and is not tangled or stuck.
  • Gently push the float down until it reaches its lowest position. The pump should stop.
  • If the float is stuck against the pit wall or discharge pipe, free it. If the float cord or rod is too long, adjust the tether per the manufacturer instructions.
  • Good: Pump stops when you lower the float—float may have been stuck or misadjusted. Bad: Pump keeps running even when you lower the float—proceed to Check switch.

Check switch

Goal: Rule out a faulty float switch.

  • If the float moves freely and the pump still does not shut off, the switch may be faulty. Check the float switch wiring for damage or loose connections. Unplug the pump before inspecting.
  • For tethered floats, check the cord length. For vertical switches, check the height setting. Adjust per the manufacturer instructions.
  • If the switch is faulty, replace it with a matching part. Some pumps have a built-in switch—replace the pump. Follow the manufacturer instructions.
  • Good: Switch replaced and pump shuts off. Bad: If you are not comfortable with electrical work, call a plumber.

When to get help

Call a plumber if:

  • You are not comfortable with electrical or plumbing.
  • The switch is faulty and you cannot replace it.
  • The pump is old and replacement is needed.

Verification

  • The pump shuts off when the pit is empty or when you lower the float manually.
  • The float moves freely and triggers the pump at the correct water level.
  • No continuous running when the pit is empty.

Escalation ladder

Work from the device outward. Stop when the problem is fixed.

  1. Confirm symptom Verify the pump runs when the pit is empty and does not shut off.
  2. Float Check that the float moves freely and the pump shuts off when it lowers.
  3. Switch Check the float switch wiring and replace if faulty.
  4. Call a pro Replace pump or call a plumber if the switch is faulty.

What to capture if you need help

Before calling support or posting for help, have these ready. It speeds everything up.

  • Whether the float moves freely
  • Whether the pump shuts off when the float is lowered manually
  • Float switch condition
  • Steps already tried

Does the pump run when the pit is empty and not shut off?

Look into the pit. If the pump runs when the pit is empty and does not shut off, the pump is stuck on.

Look into the sump pit. Good: pump runs when pit is empty and does not shut off—proceed. Bad: pump shuts off when pit is empty—normal operation.

Yes No

You can change your answer later.

No action needed

The pump shuts off when the pit is empty—normal operation. No action needed.

Done

Does the pump stop when you lower the float manually?

Manually lower the float. The pump should stop. If not, the switch may be faulty.

Lower the float switch manually. Good: pump stops—float may be stuck or misadjusted; free or adjust it. Bad: pump keeps running—switch may be faulty.

Yes No

You can change your answer later.

Free or adjust the float

Free the float if stuck. Adjust the tether or switch height per manufacturer instructions. The pump should shut off when the float lowers. If fixed, the issue is resolved.

Done

Is the float switch faulty?

If the float moves freely and the pump still does not shut off, the switch or wiring may be faulty.

Check the float switch wiring for damage or loose connections. Unplug the pump before inspecting. Good: replace the switch or pump. Bad: if not comfortable, call a plumber.

Yes No

You can change your answer later.

Replace the switch or pump

Replace the float switch with a matching part, or replace the pump if the switch is built-in. Unplug before working. If not comfortable, call a plumber.

Done

Call a plumber

Call a plumber if you are not comfortable with electrical or plumbing, if the switch is faulty and you cannot replace it, or if the pump is old and replacement is needed.

Done

Reviewed by Blackbox Atlas

Frequently asked questions

Why would a sump pump not shut off?
A stuck or misadjusted float switch keeps the pump running. The float may be tangled, resting on the discharge pipe, or the switch may be faulty. Check the float first, then the switch.
How do I check the float switch?
Check that the float moves freely. Manually lower the float—the pump should stop. If it does not, the switch or wiring may be faulty. Check the tether length and switch height.
Can I fix a sump pump that will not shut off myself?
Yes, for a stuck or misadjusted float. If the switch is faulty, you can replace the switch or the pump. If you are not comfortable with electrical work, call a plumber.
When should I call a plumber for a sump pump?
If you are not comfortable with electrical or plumbing, if the switch is faulty and you cannot replace it, or if the pump is old and replacement is needed.

Rate this guide

Was this helpful?

Continue to