A. 
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.
B. 
Under special circumstances, a variance may be granted for surface discharge.
In replacement systems, flexible corrugated perforated pipe shall not be used.