Backup Sump Pump Installation Across the Carolinas

A backup sump pump is a second pump installed in the same pit as the main pump. It sits slightly higher, so it only runs when the water rises past the point where the main pump should have started. If the main pump has lost power, failed or simply cannot keep up, the backup takes over and keeps the pit from overflowing.

The backup does not replace a properly sized primary sump pump or the drainage that feeds the pit. It is a safety net behind them, part of a basement waterproofing system that keeps working when one part stops.

The most common reason is a power outage, and outages tend to happen during the same storms that can leave standing water in a basement. Other causes include a float switch that sticks, a pump that wears out after years of use, a tripped breaker or GFCI outlet, a clogged intake, and a discharge line that freezes or clogs.

Any of these can stop the main pump without warning, often at night or while no one is home. A backup pump covers the time between that failure and someone noticing it.

A battery backup pump draws on a dedicated battery that stays charged while the power is on. When the main pump stops, the battery pump runs until power returns or the battery runs down. The battery needs to be kept in good condition and replaced over time.

A backup that runs on water pressure uses the flow of water from the home's supply to pull water out of the pit, with no battery to maintain. It needs a dependable water supply with enough pressure, which some homes on wells may not have during an outage. We look at your water supply and outage history before recommending one.

A backup is most worth considering where a wet basement would cost the most or happen most often. That includes finished basements with flooring, drywall and furniture, basements that store belongings or mechanical equipment, and homes where the main pump runs often.

In coastal areas around Wilmington and Brunswick County, a high water table can keep the main pump busy even between storms, and coastal storms often bring heavy rain and outages together. In the Piedmont, long summer storms can saturate clay soil and keep water moving toward the basement after the power goes out.

We check the existing pit, primary pump, float switch and discharge line first, because a backup depends on the same pit and plumbing. If the main pump is worn or undersized, we tell you that, since replacing it and adding a backup are often done together.

The backup pump is then set in the pit with its own float, connected to its power source or water supply, and tied into the discharge, so it empties the same pit fed by the perimeter drain. We test the handoff by raising the water level with the main pump off, so you can see the backup start on its own.

A backup only helps if it works when it is needed. For a battery backup, that means checking that the battery holds a charge and replacing it when it no longer does. For either type, it means testing the pump by raising the water in the pit and watching it start and empty the pit.

Signs that the primary system needs attention, such as damp basement walls or water standing near the pit, are worth having checked, since the backup only covers for the main pump for a while.