Conversion of an existing single-family dwelling to a duplex may or may not be permissible depending on the size of the lot. See the Section titled “Is my lot size large enough to permit a septic system?†above for more details.
If the lot size is adequate to accommodate two dwelling units (for example, within the aquifer: 19,200 square feet x 2 = 38,400 square feet), conversion to a duplex may be permitted using a single septic system. The septic system must be large enough to accommodate the full occupancy of the proposed duplex, which is very likely to require construction of a new septic tank and leaching field.
Conversion of a single family home to a duplex on a lot that is sized only for a single family dwelling will not be approved by GEPA pursuant to 22 GAR §12105(e) & (f).
