It might save you the cost of a high maintenance, high power consumption, high service cost, high component replacement cost, high analysis cost system that still needs desludging every three years or so. The savings on this alone on many sites could save you the cost of the land capability assessment within a few years.
A good land capability assessment may save you a considerable amount of money on materials, materials handling with heavy earthmoving equipment and soil disturbance, retainment or assistance with the establishment of vegetation.
It will also place wastewater in logical locations for reuse by vegetation or be available for diversion in times of drought. All of these details save you money in the long term and add value to your property.
Some land capability assessments are better than others and it is worth shopping around and asking reasonable questions of prospective assessors. Some sites require more expensive up front works for long term benefit and awareness of land purchasers about the issues associated with onsite wastewater management is about to rise significantly.
What are the hard questions you should ask prospective land capability assessors?