Home » 4 Best Grinder Pumps & A Detailed Buying Guide

4 Best Grinder Pumps & A Detailed Buying Guide

Grinder pumps are an upgraded version of sewage ejector pumps. They are basically sewage ejector pumps with a grinder. Using this grinder, a grinder pump can grind up the solids in the wastewater from the house to prevent it from clogging the discharge pipes.

A grinder pump works similarly to sewage ejector pumps. It is used to send sewage from toilets and other in-house pipes from a house to the main sewage line. In some houses, there are toilets and other pipes located below the level of the main sewage line. In such cases, the wastewater from these sources won’t drain by gravity. So it needs to be pumped up into the sewers. This is accomplished with the help of grinder pumps.

Choosing the right grinder pump can be a challenging task since there are many models to choose from. Therefore, I am listing here the most popular grinder pumps proven to be reliable and long-lasting.

Grinder pump model Max. Flow Rate Max. Head Ideal for
Zoeller 803 35 gallons per minute 35 ft 25 ft head, 15 GPM
Liberty PRG101A 46 gallons per minute 50 ft 35 ft head, 20 GPM
Zoeller M805 40 gallons per minute 45 ft 30 ft head, 20 GPM
BURCAM 400416T 70 gallons per minute 25 ft 20 ft head, 20 GPM
A table comparing the best grinder pumps with each other

Technical terms

  • GPM: Gallons per minute = a unit that shows the flow rate of sewage
  • Head of a pump: the total height to which the pump can eject sewage water.

1. Zoeller 803

Zoeller-803

Highlights

  • 1/2 HP pump
  • Maximum head of 35 feet
  • The maximum flow rate is 35 gallons per minute
  • 3-year warranty

Zoeller is a family-owned water pump manufacturers in the USA boasting many decades of successful operation. Zoella 803 is one of their most popular grinder pumps.

It is a 1/2 HP pump that can pump sewage up to a height of 35 feet. It offers a maximum flow rate of 35 gallons per minute. This is grinder pump is ideal for houses that need a flow rate of 15 GPM and a total head of 25 ft. Zoeller also offers more powerful models like Z-805 and Z-807 which can deliver more flow rate and head. Given below are their performance curves to help you select the right model.

The Zoeller grinder pump comes with an oil-filled, single-phase motor that runs at 3400 RPM. Its grinder uses a technology called ‘Tri-Slice,’ which has three independent cutting channels to deliver 250,000 cuts per minute. That’s huge considering the speed of the motor.

This grinder pump has cast iron construction with stainless steel grinding components. However, the motor’s impeller is made of high-quality plastic. Plastic has the advantage of being non-corrosive with water.

This grinder pump is suitable for both 115 v and 230-volt operations. It has an internal capacitor eliminating the need for a control panel. The motor has Class B insulation and is fully immersed in oil to withstand temperatures up to 105 degree Celcius (reference).

The discharge of Zoeller 803 is 1.25 inches, and the unit comes with a 15-foot long power cord. The power cord is wet rated and is perfectly safe to be kept underwater.

This unit is covered under a 3-year warranty.

Pros

  • Ideal performance at a total head of 25 feet with a flow rate of 15 gallons per minute.
  • Stainless steel cutter and plate
  • Can handle all flushable solids

Cons

  • The rotor is made of plastic which is not as durable as cast iron

2. Liberty PRG101A

Liberty PRG101A

Highlights

  • 1 HP pump
  • The maximum flow rate is 46 gallons per minute
  • The maximum head is 50 feet
  • 3-year warranty
  • Excellent cutter system

Liberty Pumps is another family-owned business that is located in NY, USA. They have a large number of products, and most of them are manufactured in America.

The PRG101A is a popular grinder pump model of theirs. It is a 1 HP pump with an oil-filled motor to withstand high temperatures (105 C). It has a maximum head of 50 feet and a maximum flow rate of 46 gallons per minute. This grinder pump is an ideal choice for houses that need a total head of 35 feet and a flow rate of around 20 GPM. The company also has a 2 HP pump (amazon link) if you need something more powerful.

It has a patented V-Slice® cutter system that cuts through feminine hygiene products, rags, paper towels, and wipes with ease. This cutter system is useful for residential as well as commercial installations. The two blades of the rotary cutter are specially designed with a recessed area behind the cutting edge and designed to avoid like materials from binding. The stationary cutter has orifices that enable slurry to flow through at equalized pressure and velocity. The V-shape designs in the cutter, which is its highlight, helps to improve the cutting action enabling the pump to grind tougher solids.

The unit comes with a 10 foot long, UL-rated power cord that is safe to be immersed in water. You can also opt for a 25-foot power cord if necessary. With its cast-iron construction and powder-coated components, the unit is designed to prevent corrosion and rust from ruining your machine prematurely. Unlike the Zoeller model discussed above, the impeller of this Liberty grinder pump is made of cast iron.

This grinder pump is available in automatic and manual modes. Just like the Zoeller pump, this one also can be operated on 115 and 230-volt power supplies.

The discharge of this grinder pump is 2 inches. This makes it easy to replace your existing sewage ejector pump. The unit comes with a warranty of 3-years.

Pros

  • Optional 25-foot long power cord
  • Ideal for a total head of 35 feet
  • The 2-inch discharge pipe helps to easily replace the existing sewage pump.
  • Stainless steel cutter and plate
  • Cuts all sorts of flushable items including feminine hygiene products

Cons

Pricey compared to the other models listed here

3. Zoeller M805

Zoeller 805

Highlights

  • 3/4 HP motor
  • Up to 40 gallons per minute flow rate
  • Has up to 45 feet of head
  • A 3-year warranty
  • Extra fins for heat dissipation

This is an improved and slightly more powerful version of the Zoeller 803 listed above. It uses a 3/4 Hp motor to lift up wastewater to the main sewage. It can lift the water up to a height of 45 feet, and it has a maximum flow rate of 40 gallons per minute at a flow rate of 5 GPM.

This grinder pump is ideal for situations where the total head required is 30 feet. At this head, it can grind and eject 20 gallons of wastewater per minute.

As you can see in the above picture, Zoeller 805 grinder pump comes with a number of fins all over its body. These fins are for easily dissipating the heat generated by the running motor. However, as per the company, its maximum operating temperature is still the same 105 degree Celcius.

It uses a high-speed cutter that cuts 250,000 times a minute. The cutter and plate are made of stainless steel which is more resistant to corrosion than cast iron. This cutter is capable of grinding any flushable solid wastes including flushable wipes.

The impeller is this grinder pump is made of engineered plastic which is specially designed to resist corrosion. The body of the pump is made of cast iron and is powder-coated to increases its corrosion resistance.

This unit operates at both 115 volts and 230 volts. It operates automatically with the help of a piggyback float switch. Its discharge pipe is 1.25 inches in diameter which helps to increase the total dynamic head of the motor.

This grinder pump is an excellent choice for most houses. It is also covered under a 3-year warranty.

Pros

  • A good choice for a head requirement of 30 feet.
  • 3-year warranty
  • Stainless steel cutting components
  • Handles all flushable items

Cons

  • A cast iron impeller would have been better

4. BURCAM 400416T

BURCAM 400416T

Highlights

  • Dual blade grinding system
  • Cast iron and stainless steel body
  • The maximum flow rate of 70 GPM
  • The total head is 25 feet

The BURCAM grinder pump offers the highest flow rate on this list. Its 3/4 HP motor gives a maximum flow rate of 70 gallons per minute at a head of 5 feet. It can be used in houses where the maximum heads needed are below 25 feet.

This grinder pump is best used for a discharge height of 20 feet, where it can eject 20 gallons of sewage per minute.

The body of the grinder pump is made of stainless steel and cast iron. The cutter and the impeller are made of cast iron. Unlike the other models listed here, the cutting mechanism of this grinder pump is not apt for handling solids like baby wipes and sanitary pads.

However, this is the cheapest grinder pump on the list. This is apt for residential uses but not recommended for industrial applications because of its limited grinding ability.

This pump comes with a 20-foot long power cord that is wet-rated. Its motor is oil-cooled, just like the other pumps listed here, which helps to run it continuously.

The discharge pipe of this grinder pump can be fitted to any 2 inch PVC pipings. This makes it easy to replace your existing sewage pump with this model. This unit is covered under a 2-year warranty.

Pros

  • High flow rate
  • Pocket-friendly price
  • 2-year warranty

Cons

  • Cannot handle sanitary pads and such solids

Things to look for when buying a grinder pump

Grinder pumps are not one size fits all. Also, more money doesn’t mean a better pump. So before buying a grinder pump, it is important that you do due diligence. Here are the things you should know;

Flow rate

The first thing you need to find out is the flow rate requirement. The flow rate of a grinder pump is measured in gallons per minute (GPM), it is the amount of water discharged from your house per hour. The more wastewater you discharge the more should be the pumping capacity of the grinder pump.

You can calculate the minimum flow rate required based on the number of fixtures from which the wastewater is generated. The flow rate is estimated from a value called Total Fixture Units. It assigns a fixture unit value to a fixture for eg: a bathtub has a fixture unit value of 3. Using the table listed here, calculate the Total Fixture Unit value.

fixture unit value calculation
Source

Based on the Total Fixture Value you can find the corresponding minimum flow rate requirement from the graph below;

Head requirement

Sewage pumps and grinder pumps are used to move wastewater from a low level to a higher level. So to choose the right grinder pump for your home, it is important that you know to what height the sewage needs to be moved. This height is called the head of a pump. The maximum heads of grinder pumps differ with models. The more horsepower a pump has the more is its head.

The maximum head given in the specification sheet of a grinder pump is its dynamic head which is a total of its static head and friction head. The static head of a pump is the physical height to which the sewage need to be pumped and the friction head is the extra head required to overcome the friction in the pipe. Head calculation can be very confusing, so here is a great guide to calculate the total dynamic head required for your grinder pump – http://www.sspma.org/uploads/8/3/9/2/8392851/sspmasewagepumpsizing.pdf

Once you have the minimum head and flow rate values, you can decide what grinder pump you need by inspecting its performance curve. A performance curve is a graph that comes in the specification sheet of a grinder pump which shows its relation between the head and flow rate. Flow rate and head are inversely proportional ie, the more height you need to pump the wastewater the less flow rate a grinder pump can deliver.

But the flow rate and head of the pump shouldn’t fall below the minimum values you calculated. By going through the performance graph, you can easily find out whether a grinder pump model can deliver the required flow rate for the head you need.

Flow rate and head requirement are the most important things you should consider before buying a grinder pump.

Residential or commercial application

Another thing to consider before buying a grinder pump is whether it is for residential or commercial applications. This is because grinder pumps cannot grind everything that comes to it. In a residential setup, you have control over what reaches the grinder pump. However, in a commercial space, this control is much limited. So for a commercial application, more importance should be given to the grinding ability of the pump.

Dual cutter design vs bladed cutter design

The grinders of some grinder pumps have a dual cutter design while others use a bladed design. The former design provides more surface area for cutting. Since the cutting torque is distributed throughout the whole area it may not be able to handle tough solid wastes. A bladed design offers a smaller cutting area which helps to concentrate all the torque to but tougher wastes. For this reason, the former type is suitable for residential application and the latter for commercial purposes.

Build quality

The build quality of a grinder pump is important as it is kept underwater. Most grinder pumps are made of cast iron which is great for dissipating the heat it generates. The casings are often powder-coated to prevent them from rusting.

It is also important that the grinder pump has a reliable O-ring to prevent water and moisture from getting into its motor.

Some grinder pumps use hollow floats while some use solid ones. Both types of floats work the same. However, over the course of time, water can leak into the hollow floats making them lose their buoyancy. This doesn’t happen if the float is solid.

Cutting ability

Grinder pumps are installed in situations where the wastewater coming from the house has solids that need to be ground. A grinder pump grinds solids using a cutter installed at its entry point. The design of this cutter and what it can cut varies with models. But they are generally expected to handle sanitary pads and flushable wipes once in a while.

What types of wastes can a grinder pump handle?

Grinder pumps are used to handle the following types of wastes:

  • Human waste
  • Liquid waste from toilets and urinals
  • Solid waste like garbage, paper, cloth etc.
  • Sewage sludge from septic system.
A video showing a grinder pump grinding solids

Do you really need a grinder pump?

When looking for a grinder pump, you have to be sure that you need one. Because there are many scenarios where people want to replace their sewage pumps solely because they think grinder pumps are better.

This mentallity cannot be more wrong. Grinder pumps are not a better replacement of sewage pumps. You should buy a grinder pump only if;

  • You have a high-pressure sewage main so you need a pump that can exert more force
  • You have a high head requirement

In any other cases, opt for a regular sewage pump. This is because even though grinder pumps can grind solids, it comes with many disadvantages.

Cons of grinder pumps

  • Grinder pumps are prone to clogging
  • They are costly
  • They have high energy expenditure
  • Their life expectancy is short.

If you decide that you need a grinder pump, the ones I listed above are the ones proven to be the best.