For rural projects with stand-alone effluent treatment system, the design and detailing of the system should be carried out at ‘Design’ stage in order to demonstrate compliance with part H of the building regulations. For varies reasons it may become problematic for projects if the design & detailing are not address at this stage.
Crucial to this is the accuracy of the site suitability report, submitted at planning stage. The report submitted is typically for planning purposes only and lacks detailed construction information. Thus should not be relied upon by the designer certifier or assigned certifier. A qualified & experienced site assessor should be engaged to finalise design & compile the construction information. It is the view of the author, the assessor should revisit the site to supplement the initial report and confirm its accuracy as he/she will be taking responsibility for the system being signed off on as part of the ancillary certification.
It is an area fraught with danger, not just for the ancillary certifier, but also the assigned certifier and ultimately the home owner, who will be relying on the competencies of the ancillary certifier to protect their interests.