Do I need a permit for a retaining wall in WA?

The 500 mm rule

Under the WA Building Regulations 2012, a retaining wall that retains more than 500 mm of soil needs a building permit from your local council, and the application must include an engineer-certified design. Walls retaining 500 mm or less are generally exempt — unless they're adding height to an existing wall, are part of other building work, or are needed to protect adjoining land.

City of Mandurah

Walls over 500 mm need a building permit with engineer's details and a contour survey. Fill over 500 mm can also need planning approval and neighbour consultation. Excavating closer to a boundary than the depth of the excavation needs the neighbour's consent (a BA20 form) or engineer certification. Walls within 6 m of a canal wall are often exempt from planning but still need the building permit.

Retaining walls Mandurah — terraced limestone block retaining wall with steps

City of Rockingham

The same state rule applies: building permit and engineer's design over 500 mm. Rockingham also limits what you can do on the verge, and estate design guidelines in Baldivis, Golden Bay and Secret Harbour sometimes specify wall materials and heights on front boundaries.

Shire of Murray (Pinjarra, Yunderup, Ravenswood)

Any wall over 500 mm needs a permit with an engineer's design, and the wall plus its footing must stay inside your boundary. On Canal-zoned lots — South Yunderup, North Yunderup — planning approval is always required for retaining walls, regardless of height.

What it costs and how long it takes

In the Perth market, council approval for a wall over a metre typically costs around $945 and the engineer's certificate around $1,050, though simple designs are cheaper. Allow two to four weeks for approval. We organise the engineer, lodge the application and build to the certified design, so you don't have to chase anyone.

Related services

Price ranges are Perth–Mandurah market guides at the time of writing, not quotes. Rules summarised from Water Corporation, WA Building Regulations 2012 and council guidance — confirm with your council.