Gateway/Sump pump
Sump pump
How a sump pump keeps a basement dry, the ways it fails during St. Louis storms, backup options, and why sump failure is an insurance endorsement question.
| Purpose | Removes groundwater that collects in a basement sump pit |
|---|---|
| Types | Submersible, pedestal; battery or water-powered backup |
| Common failures | Power outage, stuck float switch, undersized or clogged pump, blocked discharge |
| Insurance | Usually needs a water backup endorsement |
How it works
A sump pump sits in a pit (the sump) at the lowest point of a basement or crawl space. Drain tile around or under the foundation carries groundwater to the pit. When the water rises, a float switch turns the pump on and it pushes the water through a discharge pipe to the outside, away from the foundation. Without it, groundwater and hydrostatic pressure push water through the floor and walls.
Types
- Submersible: the motor sits sealed in the pit. Quieter and common in finished basements.
- Pedestal: the motor sits on a column above the pit. Easier to service.
- Battery backup: a second pump that runs when the power goes out.
- Water-powered backup: uses municipal water pressure to pump, with no electricity needed.
Why they fail
Most sump failures we see happen during the same storm that sends the most water to the pit: the power goes out, the float switch sticks, the pump is too small for the inflow, debris clogs the intake, the check valve fails, or the discharge line is blocked or frozen. Pumps also wear out with age. A pump that runs constantly in normal weather is a sign of a high water table or a problem worth checking before the next storm.
Testing and maintenance
Pour a bucket of water slowly into the pit and confirm the float lifts, the pump starts, the water drains and the pump shuts off. Clear debris from the pit, make sure the discharge outlet outside is open and points away from the house, and test the backup by unplugging the primary pump. Do this before the spring storm season.
Insurance
Water from a failed sump pump or overflowing sump is usually excluded from a standard homeowners policy unless the policy has a water backup endorsement, and endorsement limits vary widely and are often well below the cost of restoring a finished basement. It is not flood damage, so flood insurance generally does not pay for it either. Check your declarations page for the endorsement and its limit.
Key takeaways
- Sump pumps fail most often in the storms they are needed for; a backup pump is the main protection.
- Test the pump and backup before storm season.
- Sump failure damage usually needs a water backup endorsement to be covered.
Related glossary terms
Related services and guides
- Sump pump failure cleanup
- Basement flooding cleanup
- Emergency water extraction
- Basement and storm water guide
- Basement water in Greater St. Louis: flood, sewer backup or sump failure (PDF white paper)
Identifiers
References
Reviewed by Jake Lusby, owner of Gateway Water & Mold. Part of our entity reference pages. See our editorial policy to report an error.
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