Explaining Lift Stations

Date Published: July 1, 2024

Lift stations can be found in many residential homes, and play an integral part in managing wastewater flow. They are typically located on the lowest level of the building, such as a basement. We will often have clients wondering what they are, sometimes confusing them with sump pumps.

While a lift station does function similarly to a sump pump, it certainly serves a different purpose. We wanted to set the record straight about lift stations. So naturally, we decided to write a blog about them!

What Is A Lift Station?

A lift station (also know as a pump station or sewage ejector pump) is an electronically powered pump that is designed to transport liquid (sewage) from a lower elevation to a higher elevation. These devices are implemented in scenarios where wastewater cannot drain toward the main city line or septic tank through gravity and slope alone.

How Does It Work?

Wastewater is drained into the tank of the lift station, commonly referred to as a wet well. The pump, which is either located at the bottom of the wet well or just outside of it, is attached to a float switch. As the wet well fills and the water level rises, the float will rise until it reaches a pre-determined threshold. Upon reaching this point, the float will activate a switch that tells the pump to turn on and begin moving the water out of the tank.

The wastewater is pumped out of the tank and up into the main residential waste line, which subsequently travels to the main city sewer line or a septic tank.  The pump will continue to work until the float reaches a desired point below the threshold.

lift station diagram

Why Are Lift Stations Used?

One of the common scenarios that will call for lift stations is when the main drain line is located above certain drainage elements in a home. This is especially common with basements.

Say you are renovating your basement and want to add a bathroom. Since there was no prior drainage lines located in the basement, there will be nowhere to channel the basement wastewater by natural flow. This is a job for the lift station! All the basement drainage can be directed into a wet well and then lifted up to the main drainage line on the floor above.

A lift station is a great alternative to costly excavation projects. Instead of having to dig down far enough to allow basement drainage to successfully leave a home through natural flow, many builders will utilize a lift station. That way they will not not have to dig as deep, thus saving time and money.

Lift stations are also used when the city sewer main is higher than the drain lines in the lower parts of a home. When building a home, contractors obviously can’t adjust the depth of the city sewer line. So instead, they must make sure that the main line leaving the home is at a higher elevation than the city line. Lift stations will help to move any wastewater up to that optimal elevation. This is really common to see in older neighborhoods where city pipes were installed years before basement finishes were popularized.

You also see lift stations in homes where septic systems are present. Because septic systems are generally installed close to the surface, there isn’t always a big elevation change between the home and the septic tank. Because you need a certain amount of “fall” in your pipe, often times a lift station is needed if a basement is present.

Lift Stations Vs. Sump Pumps

As stated above, lift stations do bear certain similarities with sump pumps – both are pits in the ground, usually located in basements. However, there are several defining characteristics that separate the two.

The main difference between these two devices is their respective functions. We have already talked about a lift station’s purpose – it is meant to move sewage from a low point to a high point. The sump pump’s function is to collect and remove any water that makes its way into the home underground. In other words, it protects your basement from flooding rain or ground water.

lift station

Lift Station

Sump Pump. Image sourced from https://drycretewp.com

They also both have several physical features that set them apart. First, lift stations usually have bolted lids in order to keep hazardous sewage fumes from entering the living space. On the contrary, sump pumps generally will have removable lids and you can usually view into the pit through some type of hole or a clear lid.

Additionally, a sump pump will usually only have one pipe coming out of its top (as shown above) – the discharge pipe, while a lift station has two pipes. One pipe is to allow for ventilation and the other is the discharge pipe.

Finally, the devices differ based off of where they discharge their respective liquids. A sump pump’s discharge pipe will normally run through the foundational wall and expel excess liquid somewhere outside of the home. The lift station, on the other hand, ejects wastewater from its tank directly into the main sewer line of the home.

Inspecting Lift Stations

While our inspectors do not physically open a lift station to inspect its inside, they can take several other steps to evaluate its condition and functionality.

They can, of course, conduct a visual inspection to ensure there are no leaks and that all visible parts are intact and in good condition. They also test the outlet from which the lift station is powered to make sure it is operational. Finally, they will run water to make sure that the pump is kicking on properly. Keep in mind that it’s always a good idea to have your lift station periodically inspected and tested by a plumbing specialist.

We hope that this article has given you more insight into the functions and uses of lift stations. If you have any questions, you can feel free to reach out to us through our Ask Your Inspector program.

If you are based in Colorado and are in need of home inspection services, we hope you consider Scott Home Services. Visit us online for more information or contact us to book your services today!

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About the Author: Chris Kimmel

Chris Kimmel worked as an Associate Home Inspector for two years, handling numerous services including sewer scope inspections, pest inspections, mold air sample testing, radon testing, and water quality testing. Chris now works with Scott Home Inspection as a Content Writing Specialist.

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