A mound septic system is one of the most common alternatives to a conventional drain field when site conditions make standard installation impossible.
A mound system is an above-grade septic drain field built on a raised mound of engineered fill soil. Instead of burying the drain field below grade, the field is elevated to create the necessary separation between the effluent dispersal area and the seasonal high water table or bedrock.
Effluent from the septic tank is pumped to distribution pipes buried within the mound. The effluent percolates downward through the imported fill soil (typically sand), receives treatment, and ultimately reaches the native soil — but now with adequate vertical separation from groundwater.
Mound systems are more expensive than conventional systems due to fill material, pump chamber, pump, and engineering. Typical costs range from $15,000 to $35,000 installed, compared to $10,000–$20,000 for a conventional system.
Use our free calculator to get the right tank size for your home in under 2 minutes.
Use the Free Calculator →A properly designed and maintained mound system typically lasts 20–30 years. The pump and mechanical components will need servicing or replacement over time.
No. The mound and a designated setback area must remain clear of structures, vehicles, and deep-rooted vegetation.
Yes — when properly designed and maintained. Mound systems are often required precisely because they provide better protection for groundwater than poorly sited conventional systems.
More than a conventional system. In addition to standard tank pumping, the dose pump needs annual servicing and the mound surface needs regular mowing. Many counties require a maintenance contract.