Sketch of a common sewage grinder pump used in a modern basementGuide to Septic Grinder & Sewage Ejector Pumps

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Sewage grinder pumps / sewage ejector pumps:

This article explains the differences between and gives installation and maintenance advice for Sump Pumps, Sewage Ejector Pumps, Septic Grinder Pumps, Sewage Pumping Stations, & Septic Pump Alarms. We discuss sewage grinder pump types, sizes, voltages, horsepower, installation and maintenance.

We also give piping size recommendations for sewage pumps and effluent pumps based on the ejector pump rate in gpm. And we include a list of manufacturers of sewage pumps, septic pumps, effluent pumps, and grinder pumps.

An Environment One Corporation grinder pump schematic sketch is shown at the top of this article.

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What is a Sewage Ejector Pump? Where are they used?

Photo of a common sewage ejector pump used in a modern basement

How to buy, install, inspect, & maintain Septic tank pumps, septic grinder pumps, septic effluent pumps

What is a Sewage Ejector? Sewage ejector pumps & What's the difference between an effluent pump, sewage ejector pump, and grinder pump? Recommended pipe diameters for sewage pump installations.

[Click to enlarge any image]

Advice is given for septic tank effluent or sewage pump selection, installation, maintenance, inspection, and use.

Septic pumps used for pumping air in aeration systems and septic pumps used to move effluent in a drip dispersion system are discussed under the appropriate septic system type which are outlined at SEPTIC SYSTEM DESIGN ALTERNATIVES.

Sewage ejector pumps, or sewage grinder pumps, are designed to pump residential or household sewage or blackwater to a destination such as an elevated septic tank or to a city sewer (for homes whose lower baths are at a depth below the level of their sewer line).

Sketch of a common sewage grinder pump used in a modern basementEven if a building is nearly at the same level as its septic tank or sewer line, if the geography of the site prevents sewage from flowing fast enough on its own (two-feet per second) then a sewage grinder or sewage ejector pump is needed.

Shown at left is an older model packaged sewage ejector pump provided by Environment One Corporation.

A typical application of a sewage ejector pump is in a home where a basement bathroom is located lower than the height of the sewer line which leaves the home. The sewage ejector pump lifts waste from the basement bathroom up to the sewer line where it flows out to a septic tank or community sewer.

A sewage or septic grinder pump, (there is more than one grinding method) reduces sewage to a finely ground slurry of waste and water which can then be pumped or forced to its destination. In the sewage grinder pump photo shown at above left, the number of wires and pipes at the tank tells us that this is a duplexed or two-pump system with two grinder pumps, two drains, and a tank alarm as well (the center wires).

If your building's drain system is at a level below a municipal sewer line, or if your septic drainfield or tank and fields are uphill from the building, you need a sewage grinder pump and a forced-main sewer system.

If your home is connected to a community sewer line which itself uses a pumping station to move wastewater and sewage from the community sewer to a public sewage main, see our discussion of commercial-type sewage grinder and pumping systems found at at SEPTIC PUMPING STATIONS.

What Does a Sewage Ejector Pump Look Like?

Small wastewater ejector pump Typical home sewage grinder pump

The photo at above left is a small pre-packaged wastewater ejector pump suitable for serving a sink or clothes washer; it's not a grinder pump. In the left hand photo at lower left in the picture you'll see a small white plastic water alarm that the office manager left on the floor in this area in order to detect a plumbing supply or drain leak.

The sewage ejector pump photograph at above right shows a typical plug-in sewage ejector pump used in a home basement.

Frankly, a consumer unfamiliar with these products may have trouble telling the difference by a simple exterior inspection - it's reliable to observe the product name and number and then inquire of the manufacturer about the pump's intended application and its installation requirements.

Environment One Sewage Pump Installed - exterior view (C) Environment One CorpBut in the cases above, the overall size, location, and nearby plumbing fixtures defined the probable application of each pump even for a novice inspector and where view of the septic pump was limited.

In their most common usage, packaged septic pump systems are sold in a plastic "can" which contains the grinder pump, a float control to turn the pump on and off, and watertight fittings that permit connection of the system to the building electrical system (to supply power to the pump) and to the building drain waste vent system.

The pump manufacturer will provide a table of pumping capacity needed to overcome specific head or lift requirements and length or pipe run from the pumping station to its destination.

An Environment One Corporation grinder pump outdoor installation is shown at left while a sewage grinder pump schematic sketch is shown at page top.

Separately at SEPTIC PUMP ALARM SYSTEMS we illustrate an outdoor-mounted sewage pump alarm system provided by the same manufacturer.

Sewage Ejector Pump Maintenance

Not much maintenance is required for these pumps other than clearing a blockage if you ignore our "Don't Flush" list given below. While at least some ejector pump models can tolerate being run "dry" for some time without damage, the manufacturer(s) recommend adjusting the pump float so that the liquid level in the receiving chamber never drops below the body of the pump motor.

If your sewage grinder pump or sump pump is not turning on and off correctly, check the holding tank for clogging debris and check the operation of the sewage pump float control switch - see details at the Q&A section
of Sewage Pump Clog Damage
at Septic Pump Installation Guide.

Watch out: even a sewage grinder pump is not immune from becoming blocked or damaged by mineral debris, septic tank or holding tank debris, or solids that people may flush down a drain such as condoms, wipes, even cotton swabs or perhaps dental floss. We elaborate these trouble sources
at SEWAGE PUMP CLOG DAMAGE. Quoting Weinman [1]

Sewage Ejector Pump Piping Recommendations

Most of the sewage ejector pump installations we've inspected in residential properties use 2-inch waste piping to connect the pump outlet to the building sewer line. However the pipe diameter selection is guided by the anticipated flow rate - a figure that you can find in your ejector pump's installation and operations manual. Below we quote from Hyromatic [3].

Table of Sewage Pump Pipe Sizes & Flow Rates
Pipe Diameter in Inches Ejector Pump Flow Rate in GPM
1 1/2"
2 1/2"

Ejector Pump Preventive Maintenance

As the motor is oil filled, no lubrication or other maintenance is required, and generally will give very reliable service and can be expected to operate for years on normal sewage pumping without failing. However as with any mechanical piece of equipment a preventive maintenance program is recommended and suggested to include the following checks:

1) Inspect motor chamber for oil level and contamination and repair ...

2) Inspect impeller and body for excessive build-up or clogging and repair ...

3) Inspect motor and bearings and replace as required ...

4) Inspect seal for wear or leakage and repair as required ... [see reference [1]]

Watch out: when removing a grinder pump of sewage ejector pump from its station, do not lift the pump by its electrical wiring. Doing so risks damaging the wiring and voiding the pump warranty. Lift the pump by the steel handle or attachment intended for that purpose.

Septic & Sewage Pump Manufacturers class their pumps into these categories

    • Grinder pumps, such as Zoeller's 810/815 Turnkey Grinder Systems, 800-series Grinder Pumps, Cold-Climate grinder pumps, Simplex prepackaged grinder pump systems, and Simplex and Duplex (two pumps) grinder systems including four outdoor use.
    • Utility, pedestal, & gas engine pumps. These are portable gas-engine powered pumps used typically in construction, service, or emergencies
    • Sewage & Dewatering pumps, such as certain Aqua-Mate Models and Waste-Mate models, and Sewage-Waste 600-series pumps
    • Sump, Effluent, Dewatering pumps, such as Water Ridd'r , Mighty-Mate, Aqua-Mate, Flow-Mate, and High Head Flow-Mate pumps - of certain models - be sure to read the manufacturer's intended use for a pump model before purchasing it

Technical review by industry experts has been performed and is ongoing - reviewers welcomed and are listed at "References." This article is part of our series: SEPTIC SYSTEM INSPECTION & MAINTENANCE COURSE an online book on septic systems. Sketches are from the Environment One Low Pressure Sewer Systems Grinder Pump catalog.

Septic Pump Articles


Continue reading at FREE-STANDING GRINDER PUMPS or select a topic from the More Reading links shown below.

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SEWAGE EJECTOR / GRINDER PUMPS at - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.

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