Last updated: October 11, 2026. General information. Your pump’s manual comes first, and anything involving electricity or plumbing repairs may need a licensed professional.
When a sump pump stops working, the cause is often simple and fixable in minutes: no power, a stuck float, a clog or a backward check valve. This guide walks through those checks in order, then explains when to stop troubleshooting and call a plumber or electrician.
Safety first
- If the basement has standing water, do not step in until the power to the area is off. Call an electrician or your utility if you are unsure.
- Unplug the pump before touching it or reaching into the pit (City of Ann Arbor).
- Use gloves, since pit water can be dirty.
The quick checklist
| Symptom | Likely cause | What to check |
|---|---|---|
| Pump does nothing | No power | Outlet, GFCI, breaker; plug directly into the wall instead of an extension cord |
| Pump hums but water does not move | Clogged intake or impeller; failed check valve | Unplug, inspect intake screen and impeller; check valve direction |
| Pump will not turn on by itself, but runs when the float is lifted | Float stuck or jammed | Clear debris; free the float from walls and pipes |
| Pump turns off too soon | Float misadjusted or failing | Adjust or replace the switch |
| Pump runs constantly | Float stuck, discharge problem, failed check valve, or a lot of incoming water | Check float, discharge and check valve; see grading and drainage |
| Pump runs but pit does not empty | Blocked or leaking discharge, backward check valve | Inspect the line for clogs and leaks |
Step 1: power
Estes Services lists power problems first for good reason: the pump may be unplugged, the breaker may have tripped, or an extension cord may be causing trouble. Test the outlet with another device, press the GFCI test and reset buttons, and plug the pump directly into the wall (Farmers recommends this too). Low voltage can also overheat the motor, according to Estes, so a pump that shuts off repeatedly may need a dedicated circuit assessed by an electrician.
Step 2: the float switch
The float tells the pump when to start. If it is jammed by debris, caught on the pit wall or a pipe, or misadjusted, the pump may never start or may shut off early. Lift the float by hand. If the pump starts, the float was the problem. Clear anything that has fallen into the pit. If adjusting the float does not fix early shutoffs, Estes says the switch may need replacing.
Step 3: clogs
Debris can block the impeller, the intake screen or the discharge line. Unplug the pump, lift it out if possible, and inspect the intake and impeller for debris and damaged blades (Estes). Ann Arbor says to remove silt, rocks and pipe fragments from the pit. Sand at the bottom is normal; heavy sediment points to a footing drain problem and calls for a contractor.
Step 4: the check valve
The check valve keeps water from flowing back into the pit. Estes says it can be installed backward or stuck closed, in which case the pump runs without moving water. Confirm the flow direction and that it opens freely. Ann Arbor also says the small weep hole above the pump should be open, because it prevents an airlock that makes the pump spin without pumping.
Step 5: the discharge line
Look over the line for clogs, cracks, loose joints and leaks that send water back into the basin. Farmers recommends checking it every 3 to 4 months and before winter for ice. Make sure the water ends up away from the foundation. Madison notes that if the discharge slopes back toward the house, water recirculates into the sump.
Step 6: age and wear
Estes and Farmers both say most sump pumps last roughly 7 to 10 years. Worn impeller blades reduce performance and call for an impeller replacement; if the motor is worn out, replacement is usually the better route. If the pump still will not run after these checks, it may have failed (Estes).
What to do during a failure
- Stay out of water near live electrical equipment.
- If safe, bail water with buckets or a wet vacuum and move belongings off the floor.
- Use a backup pump if you have one. Ann Arbor says to test it periodically so you know it works.
- Call a licensed plumber for pump and plumbing repairs, or an electrician for power and battery backup issues (Farmers).
- Photograph damage in case you file a claim. Farmers notes standard homeowners policies typically exclude water backup unless you add coverage.
When it is not the pump
A perfectly good pump can still be overwhelmed. If it runs constantly during storms and the basement still floods, the problem may be too much water arriving, an undersized pump, or a discharge issue. Look at grading, gutters and the drain system before replacing equipment. Our exterior drainage guide and interior vs. exterior waterproofing cover the options, and our sump pump maintenance checklist shows how to prevent repeat failures.
Replacing a pump
Bob Vila lists replacement as faster and cheaper than a first-time installation, taking about one hour, and puts submersible pumps alone at $100 to $400 and pedestal pumps at $60 to $170. Four Seasons lists installed prices of $1,200 to $3,000 for submersible and $800 to $1,500 for pedestal. See the cost guide for the full breakdown.
Related guides
How we put this guide together
This guide was drafted with AI assistance and then edited for the site against the public sources listed below. We are not plumbers or electricians. Troubleshooting steps combine a city checklist, an insurer and a contractor page, which we flag because contractors benefit from repair calls. If you spot an error, use the contact page and we will correct it.
Sources
- Estes Services: Sump Pump Repair and Troubleshooting (contractor page)
- City of Ann Arbor: Sump Pump Maintenance Checklist
- Farmers Insurance: How to Maintain Your Sump Pump (updated May 2026)
- Bob Vila: Sump Pump Installation Cost (updated January 2024)
- Four Seasons Heating, Cooling & Plumbing: Sump Pump Installation Cost (March 2026, contractor page)
- City of Madison: Prevent Basement Flooding
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