Sump Pump Guide: Types, Backup & When to Replace
If your basement relies on interior drainage to stay dry, the **sump pump** is what makes it work — and what fails first. It is the device that takes all the groundwater your [interior drainage system](/blog/how-waterstop-interior-drainage-protects-basement) collects and pumps it out of the house. When it stops, the basement floods. This guide covers the types, the backup that matters most, and how to keep yours running.
What a Sump Pump Does
Water that reaches your foundation is collected by weeping tile and channeled to a **sump pit** — the lowest point in the basement floor. As water rises in the pit, a float switch turns the pump on, and the pump ejects the water through a discharge pipe to the outside, away from the house. When the level drops, it shuts off. It is the active heart of a drainage system that otherwise works by gravity.
Types of Sump Pump
Both are *primary* pumps. The more important decision is what backs them up.
The Battery Backup Is Not Optional
Here is the problem that catches homeowners out: **the storms that flood basements are the same storms that knock out power.** A primary pump with no backup is useless during the exact event it exists for.
Options:
A backup turns a power outage from a flooded basement into a non-event.
Don't Ignore the Discharge
Where the pump sends water matters as much as the pump:
Maintenance & When to Replace
A sump pump is a consumable. To keep it reliable:
Signs Yours Is Failing
Catch Failures Before They Flood
Because a pump usually fails silently — you find out when the basement is already wet — a connected sensor that watches the pit and alerts you to high water, pump failure, or lost power is the cheapest insurance there is. See [smart waterproofing with 24/7 sump pump monitoring](/smart-waterproofing).
What It Costs
| Item | Typical Cost (2026) |
|---|---|
| Sump pump (supply + install) | $500–$3,000 |
| Battery backup pump | $400–$1,200 |
| Full pit + pump as part of interior drainage | Included in system ($7,000–$15,000 perimeter) |
In Toronto, the [Basement Flooding Protection Subsidy](/blog/backwater-valve-toronto-basement-flooding-subsidy) covers up to 80% of a sump pump (to $2,250) plus $300 for a battery backup as of 2026.
Frequently Asked Questions
How long does a sump pump last?
Typically 7–10 years. Replace it proactively at that age rather than waiting for it to fail during a storm. Test it seasonally, and replace the backup battery every 3–5 years.
Do I really need a battery backup?
Yes, if you depend on the pump to keep the basement dry. The heavy storms that overwhelm a sump are the same ones that cut power, so a primary pump alone often fails exactly when needed. A battery backup runs through the outage — and Toronto subsidizes it.
Submersible or pedestal — which is better?
Submersible pumps are quieter, hidden in the pit, and usually higher capacity — best for finished basements. Pedestal pumps are easier to service and often last longer but are louder and visible. The right choice depends on your pit size and how the basement is used.
Why does my sump pump run constantly?
Constant running or rapid short-cycling points to a problem — a stuck float, an undersized pump, a high water table, or a failed check valve letting water drain back into the pit. It wears the pump out fast, so have it diagnosed before it fails.
What happens to my basement in a power outage?
Without a backup, the primary pump stops and the pit fills until it overflows. With a battery backup pump (or water-powered backup), pumping continues through the outage. This is the single most important upgrade for a pump-dependent basement.
Next Steps
[See Waterproofing Costs by City](/costs/waterproofing) | [Sump Pump vs French Drain](/blog/sump-pump-vs-french-drain-basement) | [Book Your Walkthrough](/start-project)
