Relevant rules in the Regulation:

  • Schedule 1, Part 1.4, Division 1.4.2, Section 1.50.

Different rules apply depending on the type of retaining wall (fill or cut) you're building:

  • fill retaining walls – above ground level
  • cut-in retaining walls – below ground level, and
  • combination retaining walls.

All retaining walls must meet the relevant general exemption criteria.

Fill retaining wall – above ground level

A fill retaining wall is a wall, or part of a wall, that keeps soil above datum ground level. They don't need DA approval if:

  • the retaining wall is:
    • between a front boundary and a building line for the block and/or if it is within 1.5m of a side boundary or rear boundary, and
    • is not higher than 0.4m above datum ground level.
  • for any other part of the wall, it isn't more than 1m above datum ground level on the lowest side of the wall, and
  • it's the only class 10 building or structure (other than a boundary fence) built within 1.5m of the boundary. Otherwise, the second exempt building or structure within boundary clearance area exemption applies. See the second building clearance area exemptions

Diagram of a fill retaining wall.

Cut-in retaining wall – below ground level

A cut-in retaining wall keeps an embankment cut below datum ground level. It doesn't need DA approval if the retaining wall is:

  • between a front boundary and a building line for the block (and/or within 1.5m of a side boundary or rear boundary), and
  • isn't higher than 0.4m above datum ground level
  • for any other part of the wall, it isn't more than 1.2m above datum ground level on the lowest side of the wall, and
  • it's the only class 10 building or structure (other than a boundary fence) built within 1.5m of the boundary. Otherwise, the second exempt building or structure within boundary clearance area exemption applies. See second building clearance area exemptions.

Diagram of a cut in retaining wall.

Combination retaining wall

This type of retaining wall is both a cut-in retaining wall and a fill retaining wall. These need to meet all the above requirements.

Diagram of a combination retaining wall.

Also see: retaining wall BA exemptions.