Guide

Sump pump guide: testing, backup power and discharge

A sump pump is easy to forget until the night it fails. A few minutes a season keeps it ready.

Calls are answered by a referral service that connects you with a local plumbing provider. How this works

How the system works

Diagram How a typical sump system moves groundwater out of a basement. This is groundwater, not sewage — a different system from sewer backflow protection.

Drain tile collects groundwater around the foundation.
Primary pump runs on household power.
Battery backup pump can run during an outage, for a limited time.
Check valve keeps discharged water from falling back into the pit.
Discharge outlet — local rules may say where it can discharge.

Simplified schematic, not to scale. Actual layouts vary by building.

Sump pump discharge pipe draining onto a lawn away from a brick house — Illustration

Testing safely

Safety first Do not reach into the pit while the pump is plugged in.

Slowly pour a bucket of water into the pit.
Watch the float rise and the pump start.
Confirm the water level drops and the pump shuts off.
Listen for water falling back after it stops (a failing check valve).
Check the outside discharge for flow.

Backup options

Backup approaches
Option	How it works	Consider
Battery backup pump	Second pump on a battery	Runtime is limited; batteries age
Water-powered backup	Uses municipal water pressure	Depends on pressure and local rules
Generator	Powers the primary pump	Safe connection and fuel
High-water alarm	Alerts you before flooding	Low cost; no pumping

Seasonal checklist

Sump checklist
When	What
Late winter	Test before thaw; clear ice from the discharge outlet
Spring	Expect frequent cycling; confirm backup is charged
Summer storms	Check alarms and backup
Fall	Clear leaves from the discharge; test again

Discharge rules

Sump water should discharge outdoors, away from the foundation. Many municipalities prohibit sump pumps or footing drains connected to the sanitary sewer — Elmhurst’s overhead sewer program, for example, requires stormwater to be disconnected from it.

Frequently asked questions

How old is too old for a sump pump?

We don’t give a number — condition and testing matter. Noisy, slow or frequently tripping pumps should be checked.

Is a backup pump worth it?

Storms that bring heavy rain often bring outages. Many owners in flood-prone areas consider some form of backup.

Sources

City of Elmhurst — Overhead Sewer Program (2023 PDF) Official / primary
City of Des Plaines — Flood Rebate Program Official / primary

Information can change; official sources control.