General note ... there are dozens - maybe hundreds - of different on-site wastewater system system types, from basic "conventional" septic systems with a septic tank and gravity driven leach lines to complete package treatment systems (like a miniature municipal wastewater treatment plant).

The idea behind this preferential tax treatment is to not penalize an individual with higher taxes if they had to sell their home to move for a job or other outstanding circumstances.

The young woman applicant works in Melbourne at a treatment center, makes decent money but also has documented trust fund income.