First allow me to echo most of the VOWRA comments.
However requiring further nitrogen reduction on AOSS's in the Chesapeake Bay watershed while still allowing conventional septic systems seems a little counterintuitive. Furthermore requiring the reduction in the entire watershed is somewhat overreaching given the relatively low percentage of nitrogen which enters the bay from onsite sewage disposal systems. Especially when these numbers are from all onsite systems including ones installed prior to more stringent VDH regulations. A more reasonable proposal would be to require nitrogen removal on properties impacted by a CBPA Resource Protection Area (RPA) or Resource Management Area (RMA). Finally if the intent is to reduce nitrogen loading into the bay from onsite system. A program could be developed to allow owners to voluntary upgrade their systems with funds from a moderate permit fee increase.