Zoeller 540 FLEX Water-Powered Backup Sump Pump System

When you have flooding risk in your basement or crawlspace, your primary sump pump might get the job done — but what happens when the power goes out? Enter the Zoeller 540 FLEX Water-Powered Backup Sump Pump System, engineered to give you true once-and-done protection. Unlike traditional battery-backed systems, the 540 FLEX uses your home’s municipal water supply pressure (typically 40–80 psi) to power a venturi-type pump mechanism with no battery to maintain, no charger to monitor and no downtime when the lights go out. It removes up to 2 gallons of water from your sump pit for every 1 gallon of water used, offering high-efficiency emergency performance. Installation versatility is built in — the unit supports both horizontal and vertical mounting and is designed to fit compact sump pits (18″ × 22″) making it an ideal choice for tight mechanical spaces. Whether you mount it overhead in the joists or beside your existing sump pump, the 540 FLEX is ready to partner with your system. Furthermore, compatibility is plug-and-play: the 540 FLEX works with any brand of existing sump pump, giving you the flexibility to choose your primary pump and add reliable backup without changing everything else.