How to Choose a Sump Pump

Most residential primary pumps run between 1/4 HP and 1 HP. A 1/3 HP pump covers the typical basement with moderate inflow, while 1/2 HP and up makes sense for high water tables, deep pits, or long discharge runs. More horsepower is not automatically better: an oversized pump short-cycles, turning on and off constantly, which wears the motor and switch out faster. Match the horsepower to how much water actually enters your pit during a hard storm, not to the biggest number on the shelf.

The big gallons-per-hour figure in marketing copy is usually measured at zero lift — basically a pump sitting in a puddle. Your pump has to push water up out of the pit and out of the house, and every foot of vertical lift (head) cuts real output. The honest comparison number is flow at a 10-foot head, which approximates a typical basement discharge. Two pumps with similar headline GPH can be hundreds of gallons per hour apart at 10 feet, so compare flow at head height across every pump on your shortlist.

The float switch — not the motor — is the most common failure point on a sump pump. Vertical float switches ride in a guide and work in narrow pits; tethered floats swing in an arc and need a wider pit but let you adjust the on/off spread; electronic switches have no moving parts but depend on clean water and consistent power. Know your pit diameter before you choose, because the wrong switch style can hang up on the pit wall or the pump itself and either never start or never stop.

Cast iron housings dissipate heat and survive decades of duty; thermoplastic housings cost less and resist corrosion but typically come with shorter service expectations. Check the power cord length against where your outlet actually sits, confirm the discharge size matches your plumbing (1-1/2 inch is the residential standard), and read the warranty term — a longer warranty is the manufacturer's own estimate of how long the pump should last. The pumps below are the primary models we compare on exactly these specs.