2015 Vermont Mantis M5Design & Installation Manual Page 8 www.eljen.com
1.0 General System Information
1.8 SYSTEM AREA SLOPE: The maximum ground slope shall not exceed 30% for wastewater systems on subdivided lots
in existence before June 14, 2002. The maximum ground slope shall not exceed 20% for wastewater systems on lots that
are subdivided on or after June 14, 2002. The limitation on maximum slope shall not apply to replacement systems that are
subject to the variance provisions of Section 1-806 of these Rules.
1.9 SYSTEM VENTING: Eljen mandates venting when the system has greater than 18” of cover material as measured
from the top of the unit to finished grade. This will ensure proper aeration of the units.
1.10 BACKFILL & FINISH GRADING: Complete backfill with a minimum of five inches of clean porous fill measured from
the top of one inch specified sand over the module. Backfill exceeding 18 inches measured from the top of the module
requires venting at the far end of the trench or bed. Use well graded sandy fill that is clean, porous and devoid of large
rocks. Do not use wheeled equipment over the system. A light track machine may be used. Divert surface runoff from the
soil treatment area. Finish grade to prevent surface ponding. Seed and loam system area to protect from erosion.
1.11 EFFLUENT FILTERS: Effluent filters are recommended as a means of preventing solids from leaving the tank.
1.12 DISTRIBUTION PIPE LAYOUT: No additional distribution pipe is needed to connect units to one another. The support
distribution pipe runs through the center of the units and provides distribution for all configurations. For bed systems, the
distal ends of rows may be connected with non-perforated pipe.
1.13 GARBAGE DISPOSALS: The use of a garbage disposal is not recommended as they can cause septic system
problems by generating an increased amount of suspended solids, grease and nutrients. Design drawings shall include a
note “Garbage disposals shall not be used with this system”.
State regulations require that the system is upsized by 25%
NOTE: Eljen recommends the use of septic tank outlet effluent filters on all systems, especially on those systems that a
garbage disposal is installed, even if the tanks design capacity has been increased. Filters with higher filtration are
recommended for systems with garbage disposals.
1.14 ADDITIONAL FACTORS EFFECTING RESIDENTIAL SYSTEM SIZE: Homes with expected higher than normal
water usage should consider increasing the septic tank volume as well as increasing the size and number of units in the
disposal area. For example: Homes with tubs holding more than 100 gallons or utilizing other high use fixtures and
homes with higher than normal occupancy should consider septic tank and drain field modifications.
1.15 WATER SOFTENERS OR CONDITIONERS: Discharge of water softener or conditioner backwash to Eljen Products
is not allowed. Discharge from these devices shall be into a separate disposal system meeting the requirements of State
and Local Regulations.
1.16 PLANS AND SPECIFICATIONS: Typical treatment system drawings and specifications are shown at the end of this
manual. When used in conjunction with a permit sketch, site specific specifications, and manufacturer installation criteria,
these documents will normally be sufficient to assure a system can be properly installed. In some instances where a
complex system is encountered, formal plans and specifications may be required. This determination is left to the
discretion of the District Health Department.
