Recently I was asked by a Queensland local government authority for advice about setback distances from a watercourse for an on-site domestic wastewater system. A site assessor engaged by the property owner had recommended a minimum setback distance of 5m. The Queensland Plumbing and Wastewater Code (2011) required a 50m minimum setback, but permitted an “Alternative Solution”. As it stood, the wastewater installation could not proceed, but the authority would accept my opinion as to whether the 50m limit could be reduced. Download my pdf which discusses (with an example) a defensible way to use the viral die-off method in Trench®3.0 to address this problem.