Sizes And Types Of Septic Pumps

Submersible Pumps

The size, shape, and capabilities of a submersible pump can vary greatly from application to application. We will discuss the differences between the many different styles of submersible pumps to help you decide which pump is right for your septic system.

Submersible pumps can be broken down into four different types:

High Head Effluent

Primarily used behind an aerobic system, high head effluent pumps output to either a spray system or drip system.


Sump/Effluent submersible pumps are designed to pump relatively clean water, usually behind an aerobic system or septic tank.

Sewage Ejector and Sewage Grinder

Both of these pumps are used to pump raw sewage. We will explain each one of these categories in much more detail below.

Questions You Need To Ask To Choose The Correct Pump

To make a decision on which type of pump will work best for your situation, you should ask yourself these questions:

-What is the application?

-What is the pump’s primary job?

-What kind of material will the pump be asked to relocate?

-Am I pumping clear water or raw sewage?

-What kind of head pressure will the pump be pushing against?

-95% of all homes using a spray or drip irrigation system shouldn’t need more than a 20 GPM high head pump.

-What are the minimum and maximum capacities your pump should handle?

Most homes need a pump within the range of 10-20 GPM (gallons permutes). 20 GPM pumps are more widely used in homes as they are more cost-effective than their 10 GMP counterparts. While 10 GPM pumps have higher head pressure, this feature is both unnecessary and more expensive

Head Pressure Explained

Head Pressure is simply the force that the pump must be vertical lift (static head) along with pipe size.

High Head Effluent Submersible Pumps

High Head Effluent submersible pumps, also known as turbine pumps or deep water well pumps, are high-pressure submersible pumps. They are primarily used in the septic system industry for spray irrigation or drip irrigation systems. These pumps are only designed to handle clear water or treated wastewater, so they are normally only installed behind an Aerobic Treatment System.

The high head effluent pumps used across the Aerobic Septic System industry are all fairly standard. You will see most of them rated 10-20 GPM and will be dimensionally very similar. There are two different pumps in this category: bottom suction pumps and mid suction pumps. It is imperative with these pumps that you clean/pump the system out before putting them in. You don’t want to put a brand-new pump in a tank that hasn’t been cleaned in 5 years. Also, if the pump went down or broke, the system likely flooded trash from the trash tank to the aerobic chamber and into the pump tank.

Mid Suction Pumps

Franklin Electric/Schaefer E-Series/Sta-Rite STEP 20

The Franklin Electric/ E-series and Sta-Rite step 20 high head effluent pump are mid-suction pumps. This means the pump will take in water at the center of the unit. Generally, this is the best design in an aerobic system because it allows any solid material that makes it to the pump tank to settle on the bottom of the tank. This prevents debris from clogging up the pump’s intake screen which would eventually cause the pump to fail prematurely.  The Franklin Electric and Sta-Rite are available in 20 GPM models and 10 GPM, however, the 20 GPM model is by far the most commonly used and less expensive.

Sta-Rite STEP 20

The State-Rite STEP 20 has been around for about 15 years. Originally, Franklin designed the motor and Sta-Rite made the pump. However, the companies split and Sta-Rite had to manufacture their own motor. In the early years, they had lots of issues with the new motors across the whole line of pumps. This has since been fixed and they make a top-notch, high-quality product that is more affordable than Franklin by a couple dollars and also has an extra year of warranty when installed by a professional. They also don’t have issues with floats, as the motor pulls 9.5 amps compared to Franklin’s 11.5-12 amps. The Sta-Rite, in our view, is tailor-made for septic applications.

Franklin Electric/Schaefer E-Series/FPS

Franklin Electric pumps will require a higher-rated float switch as they pull more amps than the Sta-Rite step 20. A Sie-Pump master float is recommended for Franklin mid-suction pumps. All Franklin pumps (Little Giant, Schaefer, and FPS models) are the same pump. The only difference is the name on the sticker. The motor and the pump end are the same things. Franklin Electric is known for their motors and used to manufacture all the pump motors for Sta-Rite and many other manufacturers. They have the motors down to a science and make arguably the best pump on the market. Some Franklin pumps have even been in operation for over 15 years. The one weakness is the type of float switch used on them. For any other pump, you can use a standard 13 amp-rated mercury float and it will give you years and years of trouble-free operation. If you put a mercury float on a Franklin and power is coming through the float as well you’re asking for problems. The pump will cause the float to fail and get stuck in the “on” position, making the pump run nonstop. With no water running through, the pump will overheat and shut down automatically. Once it cools back down, however, it’ll turn back on. The pump can do this for about 21 days and it will then completely fail. You’ll notice this is happening when your sprinkler heads are not coming up all the way and barely squirting water out.

Sta-Rite Dominator

The STa-Rite Dominator High Head Effluent pump is a bottom suction unit. This means the pump will take in the water at the bottom of the unit. Primarily used in cisterns and in applications where water pressure to the house needs to be boosted, they’ve gained popularity due to costing less than mid suction pumps.  Aerobic septic systems that use the bottom suction units should be elevated off of the bottom of the tank using a PVC pipe. Elevate them to be the same level as a mid—suction pump. If this is the kind of set up you are replacing, the Sta-Rite Dominator is going to be your best choice.

Sump/Effluent Submersible Pumps

Sump and effluent pumps are designed to handle wastewater with minimal solids or clear water. Most of our effluent pumps have a 1 1/2 NPT discharge and some of the large units even have a 2” discharge. These pumps can handle smaller solids up to 3/4” in size. These units are normally used to pump discharge from a septic tank or an aerobic system to a drain field, secondary treatment system, or surface distribution point.

There are many high-quality brands of Sump/Effluent Pumps which include Little Giant, Zoller, Ashland Pump, and Champion pump. Each of these brands manufacturers very high quality yet low maintenance units. Pumps range from 1/3 HP all the way to 2 HP. The larger the horsepower rating of a unit, the higher the head pressure and volumes of water it can handle. There are less expensive pumps at places like Home Depot or Lower, but they‘re usually made of lower quality materials like plastic. It may be more cost-effective to purchase a higher quality pump that will last 4 times as long.

Sewage Ejector Pumps

Sewage Ejector submersible pumps can handle raw sewage pumping applications. These pumps are designed to pump raw sewage wastewater, usually from a pump/lift station located in a basement or just outside of the house, over to your septic tank or aerobic septic system. Sewage ejector pumps can handle up to 12” solids and have a 2” up to a 12” discharge. Home sewer ejector pumps will be up to 3” discharge with 2” 1/2HP being the most common. Sewage Ejector pumps are great for most low pressure pumping jobs.

Sewage pumps also come from Little Giant, Zoller, Ashland Pump, and Champion pump. They range in horsepower from 4/10 up to 2 HP. Again, which unit you ultimately need depends completely on the answers to Questions 2 and 3 stated in the introduction above.

Sewage Grinder Pumps

Sewage grinder pumps are also designed to handle raw sewage pumping jobs, much like the Sewage Ejector pumps. Sewage grinder pumps, however, are much more powerful. These pumps can grind sewage into a slurry and pump it at a very high pressure to its destination. There are a couple of applications common for these pumps. The first is to pump from a residence into a shared sewer main. The second application is to pump over long distances or up and over high elevation changes.

All of our grinder pumps are 2 HP units and have 1-1/4” NPT discharges. They are also available from Little Giant, Zoller, Ashland Pump, and Champion pump. Each model comes in two forms: one with internal capacitors and one without internal capacitors. The most commonly used forms are with internet capacitors. These require no control panel for operation. The units without internet capacitors require a special control panel with built-in capacitors to operate the pump. Most manufacturers have two versions: a high volume lower head and another low volume high head. You can see these denoted by the specs and the model number either ends in HHS for High Head or HVS for High Volume. Once again, the model you choose really comes down to how you answer the questions listed above.

Important Warning: Grinder pumps must be used in situations where there will be at least a minimum of 30 feet of head pressure put on them. If they aren’t required to pump against a minimum of this much back pressure, the motor will begin to spin at an extremely high number of revolutions per minute, causing it to burn up fairly quickly. Therefore, if you are not pumping into a shared sewer main or have less than 30 feet of head, you want a Sewage Ejector pump and not a Sewage grinder pump.

With this information, you are now ready to take on the task of purchasing a new submersible pump. We have the ability to get different versions of the pump as they are listed on the website.

0 0 votes
Article Rating
f 17th 2018

Johnathan McGuire

Notify of
Newest Most Voted
Inline Feedbacks
View all comments
Jenny Watson
Jenny Watson
5 years ago

What sje pump master float do you recommend for a Schaefer? A 15 amp? Any specific model? The are many options. Thanks in advance!

4 years ago

[…] handle raw sewage like ejector pumps but are more powerful compared to the latter. They can be used to grind sewage into a slurry before […]

Aerobic Septic System Logo
Aerobic Septic System© 2024
Aerobic Septic System is your go-to source for all septic repair and installation information. Whether you're looking for advice, support or tutorials - you've come to the right place!
Would love your thoughts, please comment.x