Why Your Sump Pump Needs a Battery Backup
Your sump pump only works while it has power. The heavy storms that flood basements are the same storms that knock out the electricity — and a sump pit can fill in minutes when the ground is saturated. A battery backup sump pump is a second pump, on its own battery, that starts automatically when the main pump stops.
It also protects you when the main pump itself fails: a stuck float, a burnt-out motor or a tripped breaker. An alarm tells you the backup is running, so you can fix the main pump before the battery runs down.
We do sump pump battery backup installation in Toronto on new and existing systems. For the main pump itself see sump pump installation & replacement.
Parts of a Sump Pump Battery Backup System
Backup pump
A dedicated DC pump in the same pit, set slightly higher than the main pump.
- Separate float switch
- Own check valve
- Shares or tees into the discharge
- Starts only if water keeps rising
Battery & charger
Keeps the backup ready at all times.
- Sealed AGM or deep-cycle battery
- Smart charger keeps it topped up
- Battery box off the floor
- Optional second battery for longer runtime
Alarm & monitoring
Tells you when something is wrong.
- Audible high-water alarm
- Alerts when backup is running
- Low-battery warning
- Wi-Fi monitoring options
Choosing the Battery
How long a backup runs depends on battery size, pump size and how much water comes in.
| Sealed AGM | Standard lead-acid | |
|---|---|---|
| Maintenance | None — sealed | Check water level |
| Typical life | About 5–7 years | About 3 years |
| Cost | Higher | Lower |
| Best for | Most homes | Budget installs |
There is no single runtime figure — a pump cycling a few times an hour can run much longer than one running constantly. We size the battery for your inflow.
Signs a Battery Backup Is a Good Idea
Finished basement
Flooring, drywall and furniture are expensive to replace.
Pump runs often
The more it runs, the more a short outage matters.
Power outages in your area
Storms and outages often come together.
You travel
No one is home to notice a failed pump.
Pump is older
A backup covers you until the main pump is replaced.
History of flooding
One wet basement is reason enough.
How We Install a Battery Backup
Check the pit
Pit size, main pump, discharge and outlet.
Size the system
Backup pump and battery sized for your inflow.
Install backup pump
Set above the main pump with its own float and check valve.
Battery & charger
Mounted off the floor and connected.
Alarm
High-water and backup-running alarm installed.
Test
We cut power to prove the backup takes over.
Battery Backup Sump Pump Cost in Toronto
| Work | Typical price |
|---|---|
| Battery backup system installed | $1,200 – $2,500 |
| Replacement battery | Quoted by battery type |
| Main sump pump replacement | $500 – $1,500 |
| New sump pit + pump | $1,500 – $3,900 |
Approximate 2026 Toronto prices, not a quote. Toronto homeowners can get back 80% of the invoice, up to $300, for a sump pump battery backup (including retrofits), plus up to $2,250 for the sump pump.
Real Leaquida job siteKeeping the Backup Ready
- Test the backup every 3–6 months by lifting its float
- Check the charger light and alarm
- Replace AGM batteries about every 5–7 years, lead-acid about every 3
- Keep the battery off the floor and dry
- Test the main pump at the same time
Related Services
Why Primary Sump Pumps Fail
A battery backup for a sump pump covers the moments when the main pump cannot do its job.
Power outage
The storms that flood basements are the same storms that knock out power.
Stuck float switch
Debris or a shifted pump can jam the float so the pump never turns on.
Overload
In a heavy storm water comes in faster than one pump can move it.
Worn-out motor
Most primary pumps last 7–10 years and often fail without warning.
Frozen or blocked discharge
If water cannot leave the pit, the pump runs but nothing moves.
Tripped breaker
A GFCI or breaker trip silences the pump with no visible sign.
Types of Sump Pump Backup Systems
| System | How it works | Best for |
|---|---|---|
| Battery backup (DC) pump | Second pump on a deep-cycle battery switches on when the main pump stops or falls behind | Most Toronto homes — protection during outages |
| Combination system | Main pump and battery pump installed together on one discharge, often with a shared controller | New installations or full replacements |
| Battery-powered controller with alarm | Monitors the main pump, sounds an alarm and reports battery health | Adding safety to an existing pump |
| Generator | Powers the main pump during an outage | Homes that already have a standby generator — still no help if the pump itself fails |
Battery Sump Pump Backup in Toronto: Price and City Subsidy
Sump pump battery backup installation in Toronto typically costs $1,200–$2,500, depending on the pump, battery size and whether the pit and discharge need work.
| Item | Amount |
|---|---|
| Typical installed price | $1,200–$2,500 |
| City of Toronto battery backup subsidy | Up to $300 |
| Sump pump with alarm (if installed together) | Subsidy up to $2,250 |
| Share of invoice covered | Up to 80% of eligible cost |
Applies to eligible work completed on or after November 12, 2025, including retrofits to an existing pump. Apply within two years of the work, with a paid invoice from a contractor holding a valid City of Toronto business licence.
DIY Kit vs Professional Backup Battery Installation
Common DIY problems
- Backup pump set too high or too low in the pit
- Second check valve missing, so water cycles back
- Discharge tied in wrong and leaks under pressure
- Car battery used instead of a deep-cycle battery
- No alarm or battery monitoring
What our installation includes
- Main pump inspected first — no point backing up a dead pump
- Backup set at the right switch height
- Separate check valve and sealed connections
- Deep-cycle battery sized for your pit
- Full test with power cut and float lifted
What Happens Without a Battery Backup
Pit overflows
Once the main pump stops, a busy pit can overflow in under an hour during a storm.
Finished floors and drywall
Even an inch of water ruins flooring, baseboards and the bottom of drywall.
Insurance hassle
Many policies limit water damage claims, and a claim can raise your premiums.
Mould
Water left for more than a day or two starts mould growth behind finishes.
Battery Backup Questions
What does a battery backup sump pump do?
It is a second pump on its own battery that starts automatically if the power goes out or the main pump fails, and sounds an alarm.
How much does a sump pump battery backup cost in Toronto?
A typical battery backup installation costs $1,200–$2,500. Toronto homeowners may get back up to $300 through the City subsidy.
How long does a battery backup run?
It depends on battery size and how often the pump cycles. We size the battery for your basement and can add a second battery for longer outages.
Can you add a backup to my existing sump pump?
Yes, in most pits. We check the pit size and discharge first.
How often should the battery be replaced?
Sealed AGM batteries usually last about 5–7 years, standard lead-acid about 3 years.
Can a battery backup replace my main pump?
No. It is designed for outages and emergencies, not to run all the time.
Do I still need a battery backup if I have a generator?
A generator only helps when the power is out. A battery backup also takes over when the main pump fails, sticks or cannot keep up — which is just as common.
Is a battery backup sump pump noisy?
It only runs when the main pump cannot, so most of the time it is silent. Its alarm is meant to be loud so you know it is working.
Can a battery backup replace my main sump pump?
No. Backup pumps are built for short emergency runs, not daily use. Keep a good primary pump and let the backup cover failures.
What size battery backup do I need?
It depends on how often your pit fills. We check the inflow and size the pump and deep-cycle battery so it can run through a typical outage.
Add a Battery Backup
Tell us about your sump pump. We will check the pit and quote the right backup system.
Call now — Mon–Fri 7 AM – 4 PM(416) 992-5858Office: 58 Six Point Rd, Etobicoke, ON M8Z 2X2
Email: info@leaquida.ca