Zoeller M98 1/2 HP Submersible Sump Pump

Zoeller M98 -- high-capacity residential sump protection

The Zoeller M98 steps up to 1/2 HP for basements with high groundwater inflow rates, larger pit volumes, or elevated discharge heads above 10 feet. At 0-foot head it delivers 5,700 gallons per hour -- 40 percent more than the M53. At 10-foot head the M98 sustains 4,500 GPH, making it suitable for basement configurations where the discharge line exits high on an exterior wall or runs to a remote dry well 15 feet above the pit. The stainless steel motor shaft resists corrosion in continuous-duty applications where the pump cycles frequently enough to keep the shaft in perpetual contact with process water.

Vertical float and narrow pit compatibility

The M98 uses a vertical float switch rated for pits as narrow as 11 inches in diameter -- the same pit clearance specification as the M53. This consistency across the Zoeller line means that any homeowner upgrading from an M53 to an M98 can do so without pit modification. The float activates at approximately 5.5 inches and shuts off at 2 inches, providing a 3.5-inch working range that limits cycling frequency to protect the motor.

When to choose M98 over M53

Calculate your peak inflow rate: fill the pit with a garden hose and time how fast the water level rises to determine gallons per hour of natural inflow during a storm. Add 25 percent safety margin. If that number exceeds 3,500 GPH at your head height, the M98 is the appropriate pump. For most standard residential basements in moderate-rainfall climates, the M53 is adequate; the M98 is the right choice for flood-prone regions, basements with large interior square footage, or homes adjacent to high groundwater tables.