Short answer: A sump pump that will not start may have lost power, have an obstructed or faulty float switch, need maintenance, or have a motor problem. Before touching anything, look at the water level and the safety of the area. Do not enter standing water near electrical equipment or operate wet plugs, outlets, or breakers. If the pit is filling or water is entering the living space, seek help promptly rather than testing a potentially dangerous installation.
A sump pump normally collects water from a designated pit and moves it away through a discharge line. Its float or another sensor tells it when to run. A silent pump, a constantly running pump, and a pump that runs without moving water have different possible causes. The aim of this checklist is to record which condition you see and whether the situation is safe—not to replace an equipment inspection.
Begin with water level and electrical safety
Look from a dry, safe position. Is the sump basin nearly empty, normally wet, or rising toward its rim? Has any water reached outlets, extension cords, the pump plug, or the electrical panel? Is the building experiencing a power outage? If the area is flooded, keep people away and contact an electrician or appropriate emergency professional. Do not enter the basement to switch off power if doing so requires walking through water.
If the pit is full and water is spreading, move belongings only from a safe, dry area. A working backup pump or an alternate protected water-management plan can help, but do not improvise submerged wiring. Manufacturer manuals and CDC flood guidance both place electrical safety ahead of trying to make equipment run.
Match the symptoms to possible failure points
| Observation from a safe location | Possible explanation | What to tell the provider |
|---|---|---|
| Pit water rises; pump is silent | Power loss, float/sensor fault, motor failure | Current water level, any outage, alarm status |
| Pump hums or starts briefly | Mechanical blockage, motor fault, overload | Sound and duration, repeated shutoffs |
| Pump runs but water does not fall | Blocked or frozen discharge, check valve or impeller issue | Whether outside discharge is visible and flowing |
| Pump cycles rapidly | Switch setting, check valve, return flow or sizing issue | Approximate run and rest pattern |
| Backup alarm sounds | High water, backup battery or sensor condition | Exact alert and equipment model |
A pit with water below its normal start level may not call for the pump to run at all. Many systems intentionally wait until a float rises. Avoid forcing the float to test it if the water or wiring makes the area unsafe.
What you can observe without disassembling the pump
Is there an outage or obvious power problem?
Check whether other lights and appliances are operating from a dry, safe space. A dedicated protected outlet, a tripped circuit or loss of utility power could explain a silent primary pump. Do not remove a pump plug from a wet socket or keep resetting protective devices. If the outlet is inaccessible or damp, ask an electrician to inspect it.
Can the float move as designed?
A float switch can be blocked by the basin wall, debris or a shifted pump. It may also fail internally. If the cover can be viewed safely without touching wiring or entering standing water, note any visible obstruction; let a qualified technician handle physical adjustments unless your model’s instructions clearly permit owner maintenance under dry, disconnected-power conditions.
Where does the discharge go?
A running motor with little water movement can indicate a blocked outlet, closed valve, obstructed line, incorrect check-valve orientation, or frozen exterior run. A professional may need to inspect the pipe, air-lock requirements, pump capacity and elevation. Do not loosen a pressurized connection or send discharge where it can flow back against the foundation.
Has a backup system changed the symptoms?
Some homes have a battery backup or a second pump with a separate float. A warning light or beep can indicate high water, battery condition or test failure. Record the displayed code rather than assuming the backup will work indefinitely. A pump using the same failed power source as the primary is not independent during an outage.
Safe maintenance planning for a healthy system
Manufacturer recommendations vary. WAYNE’s sump pump guidance describes checking the basin, switch movement, power connection and pump operation according to the specific manual. Where conditions are dry and safe, some manuals allow a controlled water test. If the system has been exposed to floodwater, a child or pet could enter the area, or you are unsure how power is isolated, use professional service instead.
A useful recurring maintenance log contains the date, weather, high-water alarm condition, whether the pump ran, whether water discharged outside, and any cleaning or repair completed. Inspect the discharge outlet and surroundings after storms for obvious obstructions. Keep a record of the pump make, installation year and warranty; this helps with an urgent call.
Questions to ask a pump contractor
- Is the power supply safe, and is an electrician needed before plumbing work?
- Is the problem with the float, pump, check valve, discharge path or control panel?
- Does the existing pump have enough capacity for the measured lift and inflow?
- Would a separate backup power source or secondary pump reduce outage risk?
- Does the quote include testing the whole discharge route and alarm?
- Where will water go during repairs if the pit continues filling?
- Who is responsible for restoring disturbed piping, electrical connections or finishes?
The aim is a working system, not just a replacement motor. A new pump cannot solve an undersized discharge line, repeated power failures or water draining back into the basin.
Frequently asked questions
My sump pump is silent. Is it broken?
Not necessarily. The water may be below its start level, or the problem could be power or a float sensor. The condition must be checked safely before diagnosing the pump.
Should I manually lift the float to test it?
Not if there is standing water, wet wiring, uncertain electrical protection or an inaccessible basin. Follow the exact owner’s manual and use a professional when safety is unclear.
Why does the pump run without lowering the water?
A blocked or frozen discharge, failed check valve, damaged impeller, wrong sizing or heavy incoming flow are possibilities. A contractor can inspect the complete discharge route.
Is a battery backup enough during every storm?
No. Runtime depends on battery condition, pumping load and the design of the backup system. Inspect and maintain both primary and backup equipment according to their instructions.
Find sump pump service
Use Sump Pump Services to find the appropriate service category and Emergency Plumbing if active flooding requires urgent attention. Water Line Repair and Installation addresses a different source of water when the problem is a broken supply line rather than groundwater. Review How Listings Work before contacting independent providers and report water level, electrical hazards, and available access.
Sources and further reading
- WAYNE Pumps: Choosing the Right Sump Pump
- Canada.ca: Sump Pump Flood Preparedness
- U.S. CDC: Guidelines for Cleaning Safely After a Disaster
Educational information only; not an on-site diagnosis. Follow utility instructions, manufacturer manuals and applicable safety requirements. Independent listed providers set their own services, fees and availability.