Prevention

Sump pump failure: what to do and how to prevent it

By ARO Restorations · Updated October 5, 2026

Short answer

Check the breaker, the plug and whether the float is stuck, without standing in water. If the pump will not run, get the water out another way and start drying. A battery backup and a yearly test prevent most failures.

In this guide

Quick checks, from a dry spot

Power. Has the breaker or the GFCI outlet tripped? Is the plug still in?
Float. The float switch can jam against the side of the pit or get tangled in the cord. Free it with a stick, not your hand, if there is any water near electrics.
Discharge line. In winter the pipe outside can freeze solid. In any season it can be blocked or disconnected.
The pump itself. If it hums but moves no water, the impeller may be jammed or the pump has failed.

If the power is out across the neighbourhood, the pump cannot run without a backup.

If water is already on the floor

Stay out of it if it has reached outlets or appliances.
Move belongings up and out.
A spare pump, a wet vacuum on a GFCI outlet or a generator can hold the level if you have them.
Take photos, including the pit and the pump.
Start drying as soon as the water is out. See what to do when your basement floods.

Why sump pumps fail

Power cuts, which tend to arrive with the storms that fill the pit
Age. Pumps wear out; many last around ten years
Stuck float switches
Frozen or blocked discharge lines
An undersized pump overwhelmed by heavy inflow
No maintenance, so nobody knows it has failed until it is needed

Preventing the next one

Battery backup pump. Runs when the power is out or the main pump fails.
High-water alarm. A cheap device that sounds, or texts you, when the pit level rises.
Test it every spring and before any long trip: pour a bucket of water into the pit and watch it start, pump and stop.
Check the discharge points away from the foundation and is not buried in snow or ice.
Replace on age, not on failure.

Is sump failure covered by insurance?

Often only if you have the right endorsement. Water entering because a sump pump failed is frequently grouped with sewer backup coverage, which is optional on most Ontario policies. Check your wording.

Subsidies

Several municipalities subsidise sump pumps and battery backups along with backwater valves. See the backwater valve guide for the programs we have checked.

How a sump pump system works

Weeping tile around the footing collects groundwater and carries it to a pit in the basement floor. As the pit fills, a float rises and switches the pump on. The pump pushes the water up a discharge pipe and out of the house, where it should run away from the foundation. A check valve on the pipe stops the water falling back into the pit when the pump stops.

Every part of that chain can fail: the power, the float, the pump, the check valve or the discharge line. Knowing which one failed tells you what to fix.

Types of pump and backup

Submersible pumps sit in the pit under water. They are quiet and common in newer homes.

Pedestal pumps have the motor above the pit on a column. They are easier to service and often last longer, but are noisier.

Battery backup pumps are a second pump on a separate float and a dedicated battery. They take over when the power is out or the main pump fails.

Water-powered backups run on municipal water pressure. They need no electricity but use a lot of water and are not permitted everywhere.

Alarms sound, or send a message to your phone, when the water in the pit rises above its normal level.

Testing yours

Make sure the pump is plugged into a working outlet
Slowly pour a bucket of water into the pit
Watch the float rise and the pump start
Check that water leaves through the discharge pipe outside
Confirm the pump stops when the pit is nearly empty
For a backup, unplug the main pump and repeat

Do this in early spring, in fall, and before any long trip.

When to replace it

Replace the pump if it is around ten years old, runs constantly, makes grinding or rattling noises, cycles on and off rapidly or has visible rust. Replacing on age costs far less than one flooded basement.

After a failure has flooded the basement

The water from a sump failure is groundwater, which is treated as contaminated once it has crossed the floor. Underpad and wet drywall usually have to come out, and the structure needs proper drying.

Questions people ask

Why did my sump pump stop working?

The most common causes are a power cut or tripped breaker, a stuck float switch, a frozen or blocked discharge line, an old pump that has worn out, or a pump too small for the inflow.

How long do sump pumps last?

Many last around ten years, less if they run often. Test yours twice a year and plan to replace it on age.

Is sump pump failure covered by insurance?

Often only with the right endorsement. Many insurers treat it under sewer backup coverage, which is optional on most Ontario policies.

Do I need a battery backup?

If your basement is finished or your pump runs regularly, yes. Storms that fill the pit are the same storms that knock out power.

Where should the sump pump discharge?

Onto ground that slopes away from the foundation, well clear of the house, and not onto a neighbour's property or a sidewalk. Many municipalities do not allow discharge into the sanitary sewer.