Section 19-13-B100a of the Public Health Code requires that a CODE COMPLIANT AREA remain available on the same lot as the structure served; and, that conforms to the requirements concerning leaching area, system spread, and separating distances of the regulations and Technical Standards in effect at the time of application. The calculation of the system area required may be derived from existing soil test data for the original system, if available. If this is not available, the applicant must arrange for soil tests to be conducted.