The four checks that matter
Most stormwater concepts are refused for the same reasons: an unproven discharge point, missing overland flow assessment, detention storage that does not match the adopted policy, and water quality targets that were never modelled.
Resolving all four before lodgement is almost always faster than defending a partially complete submission through the request-for-information process.
Discharge point first
The legal point of discharge governs the entire design. Where a site cannot drain to the street, an inter-allotment easement or a charged system may be required, and both change the levels strategy substantially.
Confirm the discharge point in writing before the layout is fixed. It is the single most common cause of late redesign.
Overland flow is not optional
Councils expect the 1% AEP overland flow path to be demonstrated, including what happens when the piped system blocks. Freeboard to habitable floor levels must be shown on the plans, not merely asserted in the report.