Best 1/3 HP Sump Pump

For many homeowners, water in the basement is always a concern. This becomes even more serious after heavy rainfall or snow. And when it comes to keeping your basement dry, your first line of defense is a sump pump.

The best 1/3 hp sump pump can easily handle 8′ – 10′ vertical lifts from the sump pit in most average-sized homes. You need to ensure that the pump you select is the right size for your sump pit.

Properly sized sump pumps can save you a great deal of money and hassle in the long run. Keep in mind that there is no correct size when it comes to sump pumps.

That is because choosing a sump pump depends on many things like the depth of the basement, the depth to groundwater, the area of drainage, etc.

However, it’s safe to say that most homeowners can easily rely on a 1/3 horsepower pump to keep their basement dry.

Top 4 Best Rated 1/3 HP Sump Pumps

Here are a couple of 1/3 horsepower sump pumps that are known for their reliable performance.

1. M53 – Zoeller 1/3 HP Sump Pump

Starting off our list with a professional-grade submersible sump pump from Zoeller. The M53 model is a 1/3 HP 115V pump that has a flow rate of 43 GPM. Let me tell you; this thing is built like a tank. It has a cast iron pump housing, motor, base, and cover. And the entire pump has powder-coated epoxy paint.

This paint makes the pump body corrosion resistant. Also, the engineered thermoplastic base of this pump ensures longer service life by protecting the internal components from rust. Even if the water in your basement is salty, that won’t affect the pump. It can continue pumping water for years.

The most unique feature of this pump is perhaps its vortex impeller design. This impeller creates a vortex-style centrifugal force that pushes the water against the pump. However, the impeller doesn’t come in contact with the water. The main advantage here is that the pump will never clog.

It’s a float-operated sump pump with no metal parts or sheets that will rust or corrode. The motor is housed in a casing that is hermetically sealed and oil-filled. It also has thermal overload protection to preserve the motor and increase the overall lifespan.


  • Stainless steel handle, guard, switch arm, and screws.
  • Thermal overload protected motor.
  • Cast iron base, pump housing, and switch case.
  • Glass-filled, vortex-style plastic impeller.


  • Somewhat expensive than other sump pumps.

2. CDU790 – Wayne 1/3 HP Sump Pump

If you are looking for the best-rated 1/3 hp sump pump, the WAYNE CDU790 is of the best for its price. It’s easy to install and provides solid performance. It also runs really quiet, and you can make it run even quieter by installing a silent check valve. On that note, keep in mind that it doesn’t come with any check valves.

This submersible sump pump features a durable cast-iron housing. If you have a sump pit that is 11-inch or larger and need a compact yet durable sump pump, this is the one. Although it is compactly designed, it runs surprisingly quiet for its size and has a long service life. For the price, it’s hard to beat this one.

The compact size and carry handle allow for easy handling and installation. To ensure maximum water flow, this pump has a 1-1/2-inch NPT discharge. Even in the most demanding applications, this pump will continue pumping without any issue because of the ceramic mechanical seals.

The vertical float switch on this pump is brilliantly designed and also very simple at the same time. You won’t have to worry about the float getting stuck or getting damaged either. To protect the switch from hang-ups, the CDU790 comes with a unique float guard.


  • It runs much quieter than regular 1/3 HP sump pumps.
  • A durable cast-iron base and housing.
  • Minimized clogging and reduced airlock.
  • Designed for standard plumbing installations.


  • It doesn’t come with a check valve.

3. Superior Pump 92333 – 1/3 HP Pedestal Sump Pump

Sump pumps from Superior Pump company are known for their durability and longer-lasting performance. This one is no exception. It’s a 1/3 HP pedestal sump pump that is powerful enough to move up to 3,000 gallons of water per hour. If you need a pedestal unit, pick this one for your sump pit.

This pump features tough thermoplastic construction. However, the shaft and the impeller are made out of solid steel. The solid steel drive shaft is non-corrosive, and the stainless-steel impeller is clog resistant. The float switch is automatic and also fully adjustable.

The float switch has metal arms for durability and strength. This sump pump has a 1-1/4 in. NPT discharge that is suitable for household sump pump installation. If you have a sump basin that is 12-inch or larger, this will be the best 1/3 HP pedestal sump pump you can find on the market.

The Superior Pump 92333 has a thermally protected motor that is powerful and energy-efficient for longer service life and durability. Also, this one is a continuous-duty motor as it features permanent split capacitors. The power cord is 10 ft. long and is also waterproof.


  • Top inlets for increased water flow
  • Durable thermoplastic construction
  • An automatic and adjustable float switch
  • Powerful and energy-efficient motor


  • Not suitable for 11-inch sump pits

4. WaterAce WA33SAS Sump Pump 1/3 HP

The WaterAce WA33SAS is the final product on our list. And it’s also one of the best 1/3 HP sump pumps on the market for a lot of reasons. It features a heavy-duty cast iron construction which is far better than thermoplastic pumps. And the overall design ensures you experience a problem-free operation.

The heavy-duty float switch uses a stainless-steel arm and is connected to the sump pump’s top and the bottom. Even the internal connection of the switch is protected by a cast-iron housing and gasket and is also properly sealed. The float switch is the most reliable in its class.

The motor on this pump uses a permanent split capacitor that allows the pump to run for as long as the situation demands. It can also be dubbed as a continuous-duty motor, but there is no fixed time frame for how long this motor can last. Since the motor uses a PSC, it creates less heat and draws fewer amps.

In addition to its efficient and longer-lasting motor, this sump pump also features a vortex-style impeller that allows up to ½-inch solids to pass through. This non-clogging impeller is only found on a handful of sump pumps. You can easily use this sump pump if you have an 11-inch diameter sump basin.


  • The most reliable and the strongest float switch system.
  • Thermal overload protected, PSC motor.
  • Heavy-duty cast-iron construction.
  • Thermoplastic, vortex impeller.


  • Nothing to nitpick about.

1/3 HP Sump Pump Vs 1/2 HP

As I’ve said before, there is no correct size sump pump for every home. That is because the size of the pump largely depends on the size of your sump basin, the volume of water you need to pump out of your basement, and the size of your sump pit.

What Really Matters

There is a certain rate at which the ground passes water, regardless of rainfall rates. The sump pit should not experience any real difference in how much water is running.

It will be fine to use a 1/3 HP motor. To prevent the line from backing up into the sump, use a 1-1/2″ line and a check valve just above the waterline.

Don’t get too caught up in horsepower. Instead, you should look at the vertical lift and flow rate. Those are what really matters in a sump pump.


Also, apart from the horsepower rating, there isn’t that much of a difference between a 1/3 HP sump pump and a 1/2 HP sump pump. Also, the drainage area that you have will also determine what size of sump pump you will need.

For most houses, a 1/3 HP should be enough. However, 1/2 HP sump pumps don’t cost that much, and sometimes, having a powerful pump will be worth it in the long run.


A 1/2 horsepower pump will be more powerful than a 1/3 horsepower. And a powerful motor means it will be able to lift water higher. In almost all cases, the instructions or packaging will have a diagram or chart that shows the lift or flow versus height for both sizes.

Check the vertical lift rating of the sump pump, which is given in feet. This is the height that the motor can lift water from your sump pit. As for the flow rate, you will see something like GPM or GPH.

Which One To Choose?

For most household applications, the 1/2 HP pump shouldn’t cause any problems. You would not benefit from using the larger pump in situations where the water flows into the pit is slow.

Nonetheless, the 3/4 hp pump will not be able to keep up with the flow in situations where there is rapid water flow.

Frequently Asked Questions

How many gallons of water does a 1/3 hp sump pump push out?

On average, a 1/3 HP has a GPM of 50. In an hour, this means the pump can pump approximately 3000 gallons of water. A pump that has a 1/3 HP motor can easily handle around 9 ft. vertical lifts. If you have to push water higher, the GPM will decrease.

At a given lift, all sump pumps are rated in gallons per hour. Make sure to check the specification of your sump pump.

How many amps does a 1/3 hp sump pump draw?

A 1/3 hp motor that operating at 120 volts will draw 8 – 9 amps on average. Since we are on this topic, make sure to install the pump on a dedicated circuit. When you’re installing a pump or working with electrical wires, make sure to hire a professional.

How far can a 1/3 hp sump pump push water?

It should be possible to pump water uphill 40 feet by using a 1/3 horsepower pump. It does not matter how far it pumps. The deepness of the well is more important than its diameter. A 1/3 pump can easily pull water up the well pipe if the well is shallow.

The pump cannot function properly in a deep well due to physics. Surface-mounted pumps cannot be used on wells deeper than 34 feet. So, in a nutshell, your sump basin will determine the correct number.

Do I need a 1/3 or 1/2 hp sump pump?

It depends on a lot of things. In short, go with a 1/3 HP unit if you experience normal water flow during storms. Also, if you are replacing your existing sump pump, make sure to use the same motor that you were using before.

If your previous unit got damaged due to motor burnout, there is a good chance that the motor wasn’t capable of handling the volume of water coming into the pit. This is a good indication that you will need to increase the motor capacity.

If your 1/3 HP motor wasn’t able to handle the large volume of water, increase the horsepower. It is as simple as that.


Finally, here are some questions that you should ask yourself. What is the rate at which your sump fills up? In most cases, if the water flow is normal, a 1/3 HP sump pump will suffice.

Is a high pump capacity necessary to prevent an overflow of the sump? Not really.

Having a large pump will cause it to turn on and off too often. A smaller pump will have to work harder to keep up with the flow.

Go with the best 1/3 HP sump pump and keep your basement dry for your peace of mind.

About the Author Juan Williams

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