The Board of Health, after written application therefor, hearing
thereon and good cause shown, shall, by formal resolution, grant exemptions
from the requirement for connection to the public sewer provided for
under paragraph a above, if, due to physical conditions upon the property,
including but not limited to subsurface formations or topography,
connection to the public sewer would be impracticable and result in
substantial hardship to the owner, provided, however, that the conditions
set forth in paragraph d., below shall have been met.