What should your retaining wall cost?

A ballpark from published Canberra prices, and whether your wall needs a development application or building approval under ACT rules.

1What's it made of?

2How big is it?

Its length along the ground, and its height on the low side.

Length (m)

Height (m)

3Where is it on the block?

This decides how high it can go without approval.

4What's it holding?

5Anything else?

Drainage behind the wall (recommended: without it, water pressure pushes walls over)There's an old wall to pull out firstAccess is tricky (backyard only, no machine access)

Standing by

$— – $—

ACT rules

When a retaining wall needs approval

Development application: none needed if the wall is no higher than 0.4 m in the front yard or within 1.5 m of a side or back boundary. Elsewhere, up to 1.2 m for a wall holding back a cut, or 1 m for one holding up fill, measured on the low side.
Building approval: none needed up to 1.2 m. Up to 1.5 m only if it meets the exempt building code. Above that, it needs approval, and design standards apply above 1.2 m.
The general rules still apply either way: heritage, easements, drainage clearances and protected trees can all mean you need approval.

From Planning (Exempt Development) Regulation 2023 (ACT) and ACT Planning: Check if you need a building approval (checked 17 Oct 2026). A guide, not legal advice: check the source before you rely on it.