What is a Mound Septic System?

In certain areas the soil will not absorb liquid at a sufficient rate to allow a conventional septic system. In these areas a mound system is the most common alternative. While efficient, a mound system is far more complex and costly than a standard septic system.

Septic Tank

A mound system will use a standard septic tank. Generally made of concrete, these tanks will have an inlet and outlet port as well as front and rear interior baffles. Most codes require the tank to be placed a minimum of 10 feet from the foundation of the home.

Holding Tank

In addition to the septic tank, a mound system will also have a holding tank. This tank is located lower than the septic tank and holds the waste water that is discharged by the septic tank. Unlike the septic tank, the holding tank should not accumulate any sludge.

Pump

Because the mound is on top of the ground the system cannot be a gravity system. A mound system will require a pump to be located inside the holding tank to move the water from the tank to the mound.

Mound

The mound is constructed of a series of pipes, sand fill, fabric, gravel and soil. The pipes criss-cross the top layer with gravel beneath them and sand separating the gravel from the soil. A layer of construction fabric lays atop the pipes to separate them from the dirt covering the mound.

Slope

A mound septic system will only be functional and allowable on slopes of 15 degrees or less. Like a conventional septic system, a mound system is not intended to be installed on a steep slope or incline.

References

• Mound Septic System