Where a subsurface seepage field is installed as a component part
of a private sewage system, the seepage area provided shall be in
accordance with the Private Sewage Disposal Licensing Act and Code,
225 ILCS 225/1 et seq. A minimum of 200 square feet of seepage area
shall be provided, and unless serial trenches are used, a minimum
of two individual seepage lines are required. The minimum depth of
suitable soils for a private sewage system shall be five feet, with
four feet of suitable soils under the bottom of the septic trench
or bed.