Best 1/3 HP Sump Pumps for Average Basements: Top 8 Picks (October 2026)
The best 1/3 HP sump pumps for basements include the Zoeller M53 Mighty-Mate 1/3 HP Sump Pump for a proven all-round fit, the Superior Pump 92341 1/3 HP Cast Iron Sump Pump for a vertical float switch, and the Wayne CDU790 1/3 HP Sump Pump for top-suction design.
On this page (4 sections)
The Zoeller M53 is the best 1/3 hp sump pump for many average basements, with an automatic float switch, vortex impeller and cast iron motor and pump housing. If you want a vertical float, compare the Superior Pump 92341 or Wayne CDU790; if you need a different switch style, consider the Little Giant 6-CIA.
A 1/3 HP label alone can't tell you whether a pump fits your basement. Pit diameter, discharge height, water inflow and float clearance all affect the match, so check the pump's instructions and your current setup before replacing a unit.
For sizing context, read our guide to determining sump pump size. If your basement has frequent water or a high water table, compare the assumptions in our 1/3 or 1/2 HP sump pump guide.
Our picks at a glance
-
1
Best for a proven all-round fitZoeller M53 Mighty-Mate 1/3 HP Sump Pump
9.2/10 our score
See it on Amazon -
2
Best for a vertical float switchSuperior Pump 92341 1/3 HP Cast Iron Sump Pump
8.9/10 our score
See it on Amazon -
3
- 4
Check itLittle Giant 1/3 HP Cast Iron Sump Pump
Best for a pressure-activated switch - 5
Check itLiberty Pumps 237 1/3 HP Sump Pump
Best for a magnetic float - 6
Check itSuperior Pump 92372 1/3 HP Thermoplastic Sump Pump
Best for thermoplastic construction - 7
Check itWayne SPF33 1/3 HP Thermoplastic Sump Pump
Best for a top-suction plastic pump - 8
Check itAcquaer 1/3 HP Automatic Sump Pump
Best for shallow water removal
How we chose 1/3 HP sump pumps for average basements
We compared the listed motor class, switch style, housing materials, discharge connections and stated lift or flow details. Our score weighs specs, features and buyer feedback against what you're shopping for.
A useful average-basement pump should match the basin and plumbing already in place, then turn on automatically as water rises. A top-suction intake, vortex impeller or different switch can be useful depending on debris, float movement and pit layout.
Manufacturer numbers aren't directly interchangeable when they use different test conditions. For example, a maximum lift describes a different operating point from a gallons-per-hour figure at zero lift, so use your actual discharge height and the pump curve when comparing capacity.
The models below are ordered by score, with each one matched to a distinct installation or preference. For a wider overview of housing choices, see our guide to cast iron sump pumps.
| Product | Best for | Switch | Construction | Maximum lift | Our score |
|---|---|---|---|---|---|
| Zoeller M53 Mighty-Mate 1/3 HP Sump Pump | a proven all-round fit | Automatic float-activated | Cast iron housing, motor and switch case; plastic base | 19.25 ft | 9.2 |
| Superior Pump 92341 1/3 HP Cast Iron Sump Pump | a vertical float switch | Vertical float; on at 6 in and off at 2 in | Cast iron | 25 ft stated in product bullets | 8.9 |
| Wayne CDU790 1/3 HP Sump Pump | top-suction design | Integrated vertical float | Cast iron volute, coated steel motor housing | 20 ft | 8.8 |
| Little Giant 1/3 HP Cast Iron Sump Pump | a pressure-activated switch | Pressure activated; on at 7–10 in, off at 1–4 in | Epoxy-coated cast iron housing | 18 ft | 8.1 |
| Liberty Pumps 237 1/3 HP Sump Pump | a magnetic float | Vertical magnetic float | Aluminum motor housing; polypropylene base | 21 ft | 8.0 |
| Superior Pump 92372 1/3 HP Thermoplastic Sump Pump | thermoplastic construction | Vertical float | Thermoplastic | 25 ft stated in product bullets | 7.8 |
| Wayne SPF33 1/3 HP Thermoplastic Sump Pump | a top-suction plastic pump | Automatic vertical float | Coated steel and thermoplastic | 15 ft | 7.5 |
| Acquaer 1/3 HP Automatic Sump Pump | shallow water removal | Electronic water-level sensor | Thermoplastic | 7.4 |
Which 1/3 HP sump pump fits your basement?
The Zoeller M53 is the strongest general choice here, while Wayne CDU790 and Superior Pump 92341 stand out for specific intake and switch preferences. The right pick depends on the details of your pit and discharge line.
Zoeller M53 Mighty-Mate 1/3 HP Sump Pump: Best for a proven all-round fit
- Automatic float-activated switch
- Non-clogging vortex impeller
- Cast iron motor, switch case and housing
The automatic float switch and vortex impeller make the M53 a strong fit for routine basement sump duty. Its cast iron motor and pump housing suit buyers who want a substantial submersible pump.
Pros
- Automatic float switch
- Vortex impeller
- Cast iron motor and housing
Cons
- Plastic base
- Confirm pit fit and discharge requirements
The Zoeller M53 is a good starting point when you want an automatic pump with a conventional float switch. The vortex impeller is designed to reduce clogging, and the cast iron motor and pump housing add a substantial housing around the pump's main components.
Zoeller describes the M53 as a submersible sump pump, and its product details identify an automatic float-activated switch. The pump has a plastic base, so it isn't entirely cast iron.
Its stated maximum lifting height is 19.25 ft. Check the lift requirement for your discharge route, and make sure the switch has room to move freely in the basin.
Choose the M53 for a standard sump application where its housing, impeller and float arrangement fit your needs. For a broader view of material tradeoffs, see cast iron vs plastic sump pumps.
Superior Pump 92341 1/3 HP Cast Iron Sump Pump: Best for a vertical float switch
- Vertical float switch
- Cast iron construction
- 1-1/2 in NPT discharge
A vertical float switch and cast iron body make this a straightforward automatic replacement option. The 1-1/2 in NPT discharge is a common connection size, but check your existing plumbing.
Pros
- Automatic vertical float
- Cast iron construction
- 3-year limited warranty
Cons
- Check float clearance in your pit
- Confirm lift and flow for your discharge setup
The Superior Pump 92341 is a cast iron option with a vertical float switch for automatic on and off operation. Its specified switch points are 6 in on and 2 in off, so confirm that water levels and basin space work with your installation.
The pump uses a 1-1/2 in NPT discharge and has a 10 ft cord. Superior Pump states up to 2,760 gallons per hour and a 25 ft vertical lift in its product bullets; compare those values with your discharge height and the pump curve.
This model may suit a replacement where a vertical float fits better than a tethered float. Check for obstructions that could catch or restrict the float, and compare it with our guide to vertical and tethered float switches.
Wayne CDU790 1/3 HP Sump Pump: Best for top-suction design
- Top suction design
- Integrated vertical float switch
- Cast iron volute
The CDU790's top-suction intake is designed to reduce clogging from debris at the bottom of a sump pit and to avoid air lock. Its vertical float switch supports automatic operation.
Pros
- Top-suction intake
- Integrated automatic float
- 3-year limited warranty
Cons
- Designed for an 11 in or larger basin
- Indoor use only
The Wayne CDU790 suits buyers who want a top-suction design with an integrated vertical float switch. Wayne says the intake design helps reduce air lock and clogging from debris at the bottom of a sump pit.
Its stated maximum lift is 20 ft, and Wayne gives a 4,600 GPH figure at 0 ft in its product details. The manufacturer specifies an 11 in or larger basin and indoor use, so measure the pit before choosing this pump.
The coated steel motor housing and cast iron volute offer a mixed-material construction. Choose it when those features and basin dimensions fit your setup, and review our sump pump buying guide for installation factors to compare.
Little Giant 1/3 HP Cast Iron Sump Pump: Best for a pressure-activated switch
- Built-in diaphragm switch
- Epoxy-coated cast iron housing
- Non-clog vortex impeller
The built-in diaphragm switch uses water pressure rather than a float arm, which may suit pits where float movement is a concern. Little Giant says the pump is for sump systems, not general dewatering or emergency water removal.
Pros
- Diaphragm switch has no float arm
- Cast iron housing
- Designed for continuous duty
Cons
- Switch is non-adjustable
- Not recommended for emergency water removal
The Little Giant 6-CIA uses a pressure-activated diaphragm switch instead of a float arm. It turns on at a stated water level of 7–10 in and off at 1–4 in, which can be useful where you want to avoid a moving float in the pit.
Its epoxy-coated cast iron housing and non-clog vortex impeller suit a fixed sump system. The stated maximum lift is 18 ft, and the product details specify a 1-1/2 in FNPT discharge and a 10 ft cord.
Little Giant says this pump is not recommended for general dewatering or emergency water removal. Keep that limitation in mind if you need a pump for occasional cleanup rather than normal sump operation.
Liberty Pumps 237 1/3 HP Sump Pump: Best for a magnetic float
- Vertical magnetic float switch
- Vortex-style impeller
- Deep-finned powder-coated aluminum motor housing
The 237 combines automatic vertical switching with a vortex-style impeller. Its aluminum motor housing gives buyers an alternative to cast iron models.
Pros
- Automatic vertical magnetic float
- Vortex-style impeller
- Handles 3/8 in solids
Cons
- Requires a sump pit at least 10 in in diameter
- Check basin and discharge fit
The Liberty Pumps 237 combines an automatic vertical magnetic float with a vortex-style impeller. Its motor housing is powder-coated aluminum, and the product details state that it handles 3/8 in solids.
The pump is designed for a sump pit at least 10 in in diameter. It has a 1-1/2 in discharge, so compare the outlet with your existing pipe and check room for the float to rise.
The 237 is a useful choice if you prefer a magnetic vertical float and want an alternative to a cast iron housing. Its stated maximum lift is 21 ft, but match that figure to your installed height and flow needs.
Superior Pump 92372 1/3 HP Thermoplastic Sump Pump: Best for thermoplastic construction
- Thermoplastic construction
- Vertical float switch
- 1-1/2 in NPT discharge
This automatic model pairs a vertical float with a thermoplastic body. Its discharge size matches the 92341, while the lighter material choice may suit buyers comparing pump construction.
Pros
- Automatic vertical float
- Thermoplastic body
- 1-1/2 in NPT discharge
Cons
- 1-year limited warranty
- Verify the listed lift against your installation needs
The Superior Pump 92372 offers a thermoplastic body and vertical float switch. It shares a 1-1/2 in NPT discharge size with the 92341, while using a different housing material.
Superior Pump states up to 2,880 gallons per hour and a 25 ft vertical lift in its product bullets. Its product details state a 1-year limited warranty, shorter than the 92341's 3-year limited warranty.
Choose it when thermoplastic construction is your preference and the switch and outlet suit your pit. Verify the lift and flow that apply to your discharge setup before relying on a maximum figure.
Wayne SPF33 1/3 HP Thermoplastic Sump Pump: Best for a top-suction plastic pump
- Top-suction design
- Automatic vertical float switch
- Coated steel and thermoplastic construction
The SPF33 brings Wayne's top-suction approach to a coated steel and thermoplastic build. Its automatic vertical float supports routine basement water removal.
Pros
- Top-suction design
- Automatic vertical float
- 1-1/2 in NPT discharge
Cons
- Indoor use only
- 1-year limited warranty
The Wayne SPF33 pairs top suction with a vertical float switch in coated steel and thermoplastic construction. Wayne says the intake design helps prevent debris clogs and air lock without a traditional weep hole.
The model has a 1-1/2 in NPT discharge and is intended for indoor use. Wayne states up to 3,750 GPH at 0 ft and 2,718 GPH at 10 ft, a useful reminder that flow changes as the pump lifts water.
Choose the SPF33 if you want Wayne's intake design in a lighter mixed-material pump. Its 1-year limited warranty and 15 ft stated maximum lift are worth comparing with the CDU790.
Acquaer 1/3 HP Automatic Sump Pump: Best for shallow water removal
- Electronic automatic sensor
- Turns on at 1-1/2 in and off below 1/4 in
- Thermoplastic construction
The electronic sensor starts at a low water level and the bottom-suction design can remove water down to 1/4 in. Its 1 in NPT discharge and hose adapter make it different from standard 1-1/2 in sump-pump connections.
Pros
- Automatic electronic sensor
- Removes water to a shallow level
- Includes a 3/4 in garden hose adapter
Cons
- 1 in NPT discharge differs from common sump-pump piping
- Confirm it suits your fixed sump installation
The Acquaer AUP is best suited to shallow water removal, with an electronic sensor that starts at 1-1/2 in and stops below 1/4 in. Its bottom-suction design is intended to remove water down to 1/4 in.
This pump differs from the other picks in outlet size and use. It has a 1 in NPT discharge and includes a 3/4 in garden hose adapter, so confirm the connection and whether it fits a fixed sump basin before buying.
Acquaer also describes the pump for pools, hot tubs and flooded areas. That versatility may help with occasional water removal, but don't assume the included hose adapter matches your existing sump discharge piping.
What should you check before buying a 1/3 HP sump pump?
Check the pit diameter, discharge connection, vertical lift, switch clearance and the pump's intended use before choosing a model. These details can matter as much as the horsepower rating.
How should you compare lift and flow?
Compare a pump's flow at the head height your system requires, rather than treating a maximum figure as its normal output. A discharge line that rises higher or runs farther can reduce delivered flow.
Some products give a flow figure at zero lift, while others emphasize maximum lift. Look for a pump curve or ask the manufacturer for flow at your actual lift if you need a direct comparison.
Which switch style works in a sump pit?
A vertical float needs clear space to move up and down, while a diaphragm switch senses pressure and doesn't use a float arm. An electronic sensor may start at a shallow level, but connection style and intended use still matter.
Inspect your basin for pipes, cords or walls that could interfere with a float. If you're replacing a pump, compare its switch points with the water level you need to maintain.
Does a cast iron pump always make a better choice?
Cast iron can be a useful preference for a pump housing, but it doesn't guarantee a better fit or longer service in every installation. Some models combine cast iron with steel, aluminum or plastic components.
Compare the complete construction, warranty, switch arrangement and discharge connection. Our guide to cast iron sump pump picks covers more options in that category.
Is 1/3 HP enough for an average basement?
A 1/3 HP pump can be suitable when its flow at your discharge height handles the water entering the pit. The horsepower label by itself doesn't account for basin size, pipe layout, lift or heavy inflow.
If your current pump runs often or struggles during storms, use the 1/3 vs 1/2 HP comparison and check the system with a plumber before moving to a larger motor.
Which 1/3 HP sump pump should you choose?
Choose the Zoeller M53 for a balanced combination of automatic float operation, vortex impeller and cast iron motor and pump housing. Pick the Wayne CDU790 if its top-suction design and 11 in basin requirement match your pit, or the Superior Pump 92341 if you prefer a vertical float and cast iron construction.
For a pressure-activated switch, consider the Little Giant 6-CIA. For shallow water removal, Acquaer's sensor starts at a lower level, but its 1 in outlet makes it a different fit from a standard sump-pump connection.
Our top 3 picks at a glance
-
1
Best for a proven all-round fit
Zoeller M53 Mighty-Mate 1/3 HP Sump Pump
9.2/10 our score
See it on Amazon -
2
Best for a vertical float switch
Superior Pump 92341 1/3 HP Cast Iron Sump Pump
8.9/10 our score
See it on Amazon -
3
