Liberty Grinder Pumps

What’s the difference between a grinder pump and a sewage pump?

Many people mix up Sewage Pumps with Grinder Pumps. They have a lot in common, but they’re made for different purposes. It’s not uncommon for someone to request a grinder pump when all they truly need is a sewage pump.

Gravity alone won’t be able to transfer the wastewater in a bathroom below the sewer lines, so you’ll need to choose between a sewage or grinder pump. If you’re looking for a new sewage pump, it may appear as simple as checking up the model number and ordering one, but what if you installed the wrong one the first time?

Although the names are frequently interchanged, knowing the distinction between sewage and grinder pumps is critical for getting the job done correctly the first time. Learn how to choose the best home sewage or grinder pump for the job, whether you’re replacing or installing new.

Septic grinder pumps and sewage ejector pump systems both pump raw sewage from your home to a separate location, but they do it in different ways. For example, unlike grinder pumps, sewage ejector pumps do not have grinding blades. Instead, raw sewage is moved through the bottom of the pump using impellers that spin. The sewage is subsequently forced into the discharge pipe using pressure.

Sewage Ejector Pumps

Raw sewage from your home is pumped into a septic tank or gravity flow sewer main by sewage ejector pumps. As a result, they can only pump to distances of less than 750 feet. Sewage ejector pumps, on the other hand, are designed to transfer up to 200 gallons of raw sewage per minute. This is substantially more than what septic grinder systems can pump. Sewage ejector pumps, in general, are designed to handle large volumes of sewage at low pressure.

The two-inch discharge is a fundamental element of the sewage pump.

Septic Grinder Pumps

Due to the cutter wheel, grinder pumps are larger, heavier, and more powerful than sewage pumps. It functions similarly to a powerful garbage disposal. Everything that is sucked into the pump will be chopped up by it. It will grind it into a slurry, which will then be pumped out in a reduced quantity. On a typical grinder pump, this discharge will be around one inch and a quarter. It chews things up because it doesn’t have to pass solids. It has a smaller exit, which is one of the most important features of a grinder.

Septic grinder pumps are low-volume, high-pressure systems. This means that they are better suited than sewage ejector pumps for transporting modest amounts of raw sewage over longer distances. A septic grinder pump can assist you transport sewage from your septic tank to your pressurised sewer main.

Blades inside the septic grinder pump are used to crush raw sewage into slurry before it is discharged. It is then carried to the pressurised sewer main from there.

Because the slurry is so finely ground, it will not separate from the liquid once inside the septic tank, septic grinder pumps should not be used with septic tank systems. 

This means it won’t be transferred to the secondary system, which could destroy your subsurface leach field.

Which pump to choose: grinder pump vs sewage pump

Consider the volume of sewage you need to pump, its destination, and how far it has to travel to get there when determining which pump is best for your home’s sewage pumping needs.

If you need to pump sewage to a pressurised sewer main, we propose installing a grinder pump. A sewage ejector pump is far superior to a sewage ejector pump when pumping to a septic tank or a gravity flow sewer line.

Septic grinder pumps may also pump ground sewage hundreds of feet, which is significantly further than sewage ejector pumps.

Grinder pumps, on the other hand, can only pump little amounts of sewage. Sewage ejector pumps, on the other hand, can transport large amounts of raw sewage over short distances (up to 200 gallons per minute).

It’s best to consult a professional sewage pump plumber when choosing a sewage pump system for your property. A certified plumber will be able to determine which pump is best for your needs.


Only use a sewage grinder pump if one of the following scenarios applies to your situation:

  • If you’re pumping into a pressurised sewer main.
  • When pumping for a long time (750 feet or more)
  • To elevate the sewage, you need a large vertical distance (typically at least twenty to thirty feet)

The following are some of the instances in which a sewage ejector pump will be most useful:

  • When sewage is discharged into a septic tank.
  • When sewage is pumped to a gravity sewer main.
  • When transporting sewage over short distances (750 feet or less)
  • To lift the sewage, you have a short vertical distance (under 70 feet)

To summarise, not all sewage treatment pumps are grinder pumps, and a sewage grinder pump is not always required to pump raw sewage. In most circumstances, a sewage ejector pump is the far superior choice. There are some situations in which you could use either type.

Exception to the Rule

Liberty ProVore Residential Grinder Pumps with 1.0 HP are speciality equipment designed to replace residential 4/10 to 1.0 HP sewage ejector pumps.

The 1.0 HP Liberty ProVore Home Grinder pumps are specialty machines designed to replace residential sewage ejector pumps ranging from 4/10 to 1.0 HP. There is no minimum head requirement for these machines, and they have the same cutting action as larger commercial grinder pumps, but with a smaller 1.0 HP motor. While this will pump sewage from a home to a public sewer, we do not recommend using it to pump sewage to a septic tank because the sewage will still grind into a slurry.

Still not clear which pump you need to use? Please contact us and we will be pleased to show you exactly which pump you need.