Best 1/3 HP Sump Pumps (2026)

The M53 is the benchmark for a 1/3 HP pit pump. The motor, switch case and pump housing are all cast iron, which turns the whole body into a heat sink that carries motor heat into the pit water. Heat is what kills small submersibles, so this is the reason it lasts.

A non-clogging vortex impeller sits recessed from the flow path and passes small solids without wearing against them. The switch is float activated and sealed in the iron case, so the part most likely to fail in a cheaper pump is better protected here. It costs noticeably more than the Wayne CDU790 at the same horsepower.

The tradeoff is that you pay for a name and a build, not for a bigger motor or a higher published flow. On a pit with modest inflow that is a fair trade. Check the float travel annually, clear the screen, replace the check valve before it fails, and expect long service. Year-three reality is mostly about the switch and the check valve, not the motor. If the pump has been cycling a few times a week, expect it to look and sound the same as day one.

The SPF33 publishes two flow figures: 3,750 GPH at zero lift and 2,718 GPH at a stated height. That is a 28 percent drop, and having both numbers is more useful than a single maximum. The coated steel and thermoplastic body resists corrosion without the weight of cast iron.

The vertical float switch fits narrow pits and turns the pump on automatically as the water rises. Compared with the Zoeller M53, the Wayne gives you a higher zero-lift rating and a lower price in exchange for a lighter body and shorter pedigree. Compared with the Superior 92372 at 2,880 GPH, it moves more water on paper.

Treat it as the value pick for a standard pit. Test the float twice a year, keep the screen clear and replace the check valve in step with the pump. If you buy it, also buy a spare check valve. The pump will outlast the valve more than once, and a valve swap takes ten minutes with a pipe wrench.

The CDU790 is the straightforward 1/3 HP pump for a normal basement. Top suction keeps the intake above the silt on the pit floor and avoids air lock, and the cast iron volute holds its shape where wear concentrates. Stainless fasteners and an epoxy-coated steel motor housing round out a durable build.

A three-year warranty and US assembly give it more support than the generic utility pumps in this group. The weakness of top suction is that the pump quits above the pit floor and leaves a few inches of water behind.

Against the Wayne SPF33 it trades a vertical float for a top-suction intake, and against the Zoeller M53 it trades an all-iron body for a lower cost. It is a sound default. Clear the pit of gravel, inspect the cord and check the valve yearly. Parts and service are easy to find, and a competent plumber can swap one in under an hour.

The Liberty 237 uses a deep-finned, powder coated aluminum motor housing. Aluminum conducts heat quickly and the fins add surface area, so the motor sheds heat into the pit water efficiently while weighing far less than cast iron. A vortex-style impeller reduces clogging and improves flow.

It is a good pick when you want metal cooling without the weight of iron, for instance in a pit where you lift the pump out regularly. Aluminum is lighter and corrosion resistant, though it can be less rigid than iron in rough handling.

Against the Zoeller M53, the Liberty offers a different cooling design at a similar class of price. Expect the same service routine: a bucket test each quarter, screen cleaning and a check-valve inspection yearly. The powder coat can chip if the pump is dragged across concrete, so lift it by the handle or the discharge pipe rather than the cord.

The Superior 92372 is a thermoplastic 1/3 HP pump rated for 2,880 GPH, with a 25 foot maximum lift and a 10 foot cord. A vertical float switch controls it automatically and fits narrower pits.

Its plastic body is light and corrosion proof but does not shed heat like iron or aluminum, so it suits pits with moderate duty. The 25 foot lift figure is a shutoff head, not a working flow, so do not read it as a promise at height.

Compared with the Wayne SPF33's 3,750 GPH, it moves less on paper. It is a good lower-cost pit pump or a spare. Check the float and rinse the screen each spring. It shares a 1/3 HP motor with the Zoeller M53, but the price gap is the price of the housing, not the horsepower.

The Cleartide takes a different approach: an electronic water sensor instead of a float. In auto mode it starts at about 1-1/5 inches of water and stops at about 1/5 inch, and a manual mode lets you run it dry-ish for a final pass. A 100 percent copper-wound motor is claimed to run cooler and last longer.

The sensor means no float to tangle on a cord, which is a real advantage, but it is also a newer technology with less long-term history than a mechanical float. It is a utility pump first, suited to flooded floors and cellars.

Against the Zoeller M53 it is a very different machine: lighter, cheaper and more flexible, but not designed to sit in a pit for ten years. Use it as a spare or for flood work. Keep the sensor probes clean, because a film of silt can make the electronic sensor misjudge the water level.