The allowable height for a retaining wall without requiring engineering or council approval in Australia varies across different regions.
As a general guideline, retaining walls under 600mm to 1,000mm in height is often considered low-risk and may not require approval.
However, this threshold can differ based on local regulations, soil conditions, and proximity to other structures or boundaries.
It is crucial to check with the local council or building authority to confirm the specific height limitations and any associated requirements.