M5 Series

Step into the Future with the Revolutionary Wastewater System

  • Engineered Mini-Trenches provide 3-Dimensional Performance
  • Infiltrative Surface Optimization (ISO) technology significantly increases the products' effective surface area
  • Flexible sizing offers greater design and install options
  • Light-weight and easy to install
  • No filter fabric or special end caps required
  • Made in the USA from recycled content
  • Your better wastewater disposal system

When your installation requires more performance in less space, the Eljen Mantis Wastewater Leaching System delivers.  The unique design of the Mantis System provides a two-stage Bio-Matt™ pre-treatment process that increases the soil's ability to accept the effluent, resulting in a superior leaching system in a smaller footprint.

How the Eljen Mantis M5 Works

The Eljen Mantis M5 Series is a wastewater dispersal and disposal technology that applies clarified effluent to the native soil through a proprietary filtering process.  The Mantis M5 protects the native soil's long term acceptance rate by keeping the biological growth off the native soils and within the Mantis M5 units.  Each module consists of a cuspated core surround by Bio-Matt™ geotextile fabric.  The unique design of the Mantis M5 increases the available surface area within each module.


  • The perforated Support Distribution Pipe is centered within the Mantis M5 and privdes internal distribution of septic tank effluent while securing the five Filter Support Modules.
  • The Filter Support Modules filter septic tank effluent and act as individual 3-D Mini-Trenches™ within the system's footprint.  Each module consists of a cuspated core surrounded by Bio-Matt™ geotextile fabric.  The Mantis M5's unique design increases the available surface area within each module.  This is known as Infiltrative Surface Optimization (ISO) and provides a system surface area that greatly exceeds that of the Filter Support Module, a traditional gravel trench or that of gravel replacement technology.
  • Open air channels within the Filter Support Modules support and promote fixed aerobic bacterial growth on the Bio-Matt™ geotextile fabric interface.
  • Septic tank effluent migrates through the Filter Support Modules and into the Specified Sand layer which surrounds each Mantis M5 unit. The Filter Support Module clarifies septic tank effluent and assists in its delivery to the Specified Sand.  This process promotes unsaturated flow in the Specified Sand and native soils while maintaining the native soil's structure, long term acceptance rate, and its ability to effectively absorb the clarified effluent.
  • The Specified Sand layer also protects the native soil from compaction, helps maintain existing pore spaces within the native soil column, and preserves the native soil's natural infiltration capacity which is critical for long-term performance.

Mantis M5 Design

Flexible sizing offers great design and install options.  The Mantis M5 Series has four sizes to meet the individual site's needs, and standard fittings (22°, 45°, etc.) between the unit connections help to custom "shape "the system.  

The LowPro 5.1 and 5.2 models are only 8 inches tall, significantly reducing mound sizes or installation depths when there are high limiting layers. The Mantis M5 Series can be used in a variety of configurations.  Please contact us if you would like more details.

Product Length Width Height
M5.2 5' 2' 12"
M5.2 LowPro 5' 2' 8"
M5.1 5' 1' 12"
M5.1 LowPro 5' 1' 8"




Basic Installation Steps

Please refer to your state's Design and Installation Manual for more specific installation steps.

  1. Excavate trench and place first layer of ASTM C33 Specified Sand
  2. Make sure sand is level and stabilized
  3. Install units by connecting the 4" Support Distribution Pipes
  4. Cap the 4" Support Distribution Pipe at the end of each row and begin feathering in Specified Sand
  5. Continue back filling, making sure to work the Specified Sand in between each module
  6. Finish back filling with the required amount of Specified Sand (refer to manual) on either side of the units and a minimum of 1" above
  7. Finish by covering with top soil and seeding to protect from erosion


Mantis M5 Wastewater Systems logo