Garden Retaining Walls SydneyLow Walls, Properly Drained

Where the 600mm Line Sits

Under the Codes SEPP, a retaining wall up to 600mm can generally be built as exempt development. Above 600mm it is not exempt at all and needs a Complying Development Certificate or a DA, with engineer certification sitting inside that pathway rather than replacing it. That single figure shapes most garden design on a Sydney block: two 500mm walls with a planted step between them will often get you the same level change as one 1.1m wall, without the engineering.

Exempt does not mean unconditional. The wall has to sit at least 1m from every lot boundary and at least 2m horizontally from any other retaining wall on the site, keep clear of easements, sewer and water mains, and connect its drainage to the site stormwater. Separately from the planning rules, we will not build an exempt-height wall under a driveway, pool or structure — that is a load an engineer needs to design for. Water is what actually kills garden walls: soil behind a wall gets heavier as it wets up, and a wall with nowhere to drain is being pushed by that load every time it rains. Every wall we build gets free-draining aggregate and an ag line behind it, on the smallest job as much as the biggest.

Garden Wall Essentials