Sump Pumps: Why They Fail When You Need Them

A sump pump can sit quietly for months, then face its biggest job during a heavy storm. That is exactly when many pumps fail, and a failed pump can mean a wet basement. Understanding why pumps fail helps you prevent it.

How a sump pump works

Water collects in a pit, called a sump basin, usually in the lowest part of a basement or crawl space. When the water rises, a float switch turns on the pump. The pump pushes water out through a discharge pipe, away from the house. A check valve keeps water from flowing back into the pit.

There are two main types:

• Submersible pumps sit inside the pit, underwater.
• Pedestal pumps have the motor above the pit on a column.

Why pumps fail during storms

Storms bring several risks at once:

1. Power outages. A standard pump runs on household electricity. If the power goes out during a storm, the pump stops.
2. Overwhelming inflow. During heavy rain, water may come in faster than the pump can move it.
3. Continuous running. A pump that runs for hours can overheat, especially if it is undersized.
4. Discharge problems. A frozen, clogged or crushed discharge line can stop water from leaving.

Other common causes of failure

Even in good weather, these problems build up:

• Stuck float switch. The float can get caught on the pit wall, the pump body or debris, so it never triggers or never shuts off.
• Clogged intake. Dirt, gravel and debris can block the pump's intake or screen.
• Failed check valve. If it fails, water flows back into the pit, making the pump work harder.
• Age. Pumps have a limited service life, and motors and switches wear out.
• Improper installation, such as a pit without a lid, a pump sitting directly on dirt, or a missing check valve.
• Tripped GFCI or breaker. If the pump's outlet loses power, the pump will not run.

How to test your sump pump

Test it a few times a year, and before rainy seasons:

• Make sure the pump is plugged in and the outlet has power.
• Slowly pour a bucket of water into the pit until the float rises.
• Watch the pump turn on, empty the pit and shut off.
• Go outside and confirm water is leaving the discharge pipe.
• Listen for grinding or rattling, which can signal wear.

If the pump does not start, shuts off too soon or runs without moving water, have it checked.

Adding backup protection

Many homeowners add a second layer of protection:

• Battery backup pumps run when the power goes out or the main pump fails.
• Water-powered backup pumps use municipal water pressure to remove water, where local rules allow.
• A second primary pump can share the load during heavy rain.
• High water alarms alert you when water is rising in the pit.
• Generators can keep the main pump running during outages.

Backup systems need maintenance too. Batteries wear out and should be checked.

Simple maintenance tips

• Keep the pit clean and covered.
• Make sure the float moves freely.
• Clean the intake screen.
• Keep the discharge line clear and pointed away from the foundation.
• Protect discharge lines from freezing in winter.
• Replace aging pumps before they fail.

How home warranties treat sump pumps

Some home warranty plans include sump pump coverage, sometimes as part of plumbing and sometimes as an add-on. Coverage often applies to the pump itself and may exclude battery backups, alarms, discharge lines or water damage caused by a failure. Caps may apply.

A home warranty generally does not cover flood or water damage to the home. That is typically a matter for homeowners or flood insurance, depending on the cause. Check your policies. If you have a well pump as well, its coverage is usually listed separately. Our covered items page explains common inclusions.

How Warranty Wizards can help

We help you compare home warranty plans from third-party providers and explain what each covers for sump pumps before you buy. Request a free quote at /get-a-quote/.