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How to Select a Sewage Pump


A properly working sewage pump is a necessity for homeowners with basement toilets. Sewage pumps lift flushable waste into the sewer line or a septic tank. Many people often replace their pump with same model as before. To see if that is the right case for you, consider how long the pump lasted. Check out the blog: How Long Should My Pump Last?

I will answer some of the common questions as a guide to help you size a sewage pump for your system.

How much flow do I need?

Knowing what type of flow rate is needed is a function of how many drains and the number of users that will be feeding your sewage basin. A good rule of thumb for residential use is 50 gallons per day per person.

What is the distance of the vertical lift?

Those that are familiar with the pumping industry will commonly ask “What is the Head?”, “What is the Total Dynamic Head?” or something similar. These are all questions asked to help determine the amount of pressure or force required to “push” the liquid up to where it needs to go. It is also important to consider whether the system is lifting to a septic tank without any back pressure or to a sewer system that has pressure pushing back. To learn more about calculating head check out our video on the RC Worst YouTube Channel titled “Pump Head: Simple Explanation”.

What are the solids-handling requirements?

Solids-handling requirements may be determined by local codes. Unless otherwise stated, a sewage pump should be able to handle spherical solids up to 2” in diameter.

What size pump basin do I need?

The flow rate will normally determine the size of basin required. A basin that is properly sized would allow the pump to run longer on each cycle and also to cycle less times per day. The larger the motor, the longer the run time generally needs to be and the less cycles per day that are recommended. Generally speaking the owners manual will indicate the maximum number of cycles in a 24 hour period; so take that into account along with the flow rate to determine what is right for you. The diameter of the basin required will increase with higher flow rates. Basin depth should normally be at least 24”, and deeper where greater pumping differentials are anticipated.

Do I need a Simplex (one pump) or or Duplex (two pumps) System?

A Simplex System is adequate in most residential uses. For commercial or municipal uses a Duplex System is essential. A duplex system should be considered for residential uses with high flow rates or when having a second pump gives an owner greater peace of mind.

Once you know what the flow and vertical lift requirements pump performance tables are consulted to help with final selection.

Should I buy a pump with more horsepower or a higher flow rate?

When evaluating performance curves, pumps will be more efficient in the middle of the curve, away from the maximum head or flow. Therefore, higher horsepower or flow is not always better as short cycling may reduce the life of the pump.

Looking for that peace of mind of knowing that you have the right sewage pump for your system? Call us today at RC Worst & Company for any of your pumping system questions.



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