Sump Pump

A sump pump sits at the lowest point of a basement or crawlspace in a collection pit and automatically activates when water rises above a set level. The pump forces that water up and out through a discharge line that runs to daylight, a storm drain, or a dry well—anywhere except back into the foundation. Most residential units run 1/3 to 1/2 horsepower on either 115V or 230V, with a typical shutoff head of 20–25 feet.

In the field, you'll encounter two main types: pedestal models with the motor above the pit (easier to service, less reliable in heavy water), and submersible units with the motor sealed inside the pump body (better for constant duty, harder to pull for repair). The discharge pipe must have a check valve to stop backflow and a vent hole near the pump intake to prevent vacuum lock. Many jurisdictions now require a backup power source—battery pack or generator hookup—because standard sump pumps do nothing in a power failure, which is exactly when heavy rain or snowmelt hits.

Badly installed sump systems cause more callbacks than almost any other system: discharged water that pools against the foundation, inadequate slope on the discharge line, clogged intake screens, or frozen discharge lines in winter. A properly sized pump rated for the site's water load, a sealed pit cover, and a discharge line that actually drains away are the difference between a working system and a wet basement.