External drainage
Correct drainage sizing (main drain 100mm)
Grade or fall at a minimum 1.60 or 1.65% to septic tank
Approved pipe work material used - stamp visible
Correct bedding/side support - 10mm maximum hard stone / blue metal or sparged with 1 part Portland cement and 4 parts clean sand
Vented (between last and second last fixture, <8.5m from the end of drain or >10m from a gully
Gully requirements - at least 150mm below lowest fixture and 75mm above surrounding ground level
Inspection openings (at the point of connection to septic tank, immediately at or upstream of a bend, outside the building where the WC is connected, at interval lengths of <30m where WC are connected)
If back filled, is certifying certificate required from the drainer or plumber
The required cover where applicable comments
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