W. Va. Code § 16-1-9B

Individual systems with surface water discharge may be considered for approval for a permit pursuant to section nine of this article under the following conditions: (1) To correct existing failures when other means of treatment and disposal have proven ineffective; (2) on a tract, lot or parcel of land that equals or exceeds two acres which cannot qualify for standard or alternative soil absorption systems; or (3) on existing lots which received approval under a prior permit where it has been determined that applicable standards cannot be met to qualify for a standard or alternate soil absorption system. Approval under these conditions are applicable only to single family residential units.

When installing a standard sewage disposal system, modified system, experimental system or other approved system, the reserve area shall consist of an area for the placement of the original system together with an area for replacement and upgrade of absorption field lines within the reserve area. Testing of the site for approval shall consist of a six foot hole and a percolation test of the soils.