Author: Lee Bradley, Co-Founder, Retaining Walls Direct · Last verified: July 2026 · About RWD

Person measuring retained height of retaining wall with tape measure in Perth Western Australia

In WA, the 500mm threshold is measured from finished ground level on the low side to the top of the retained face — the strictest threshold of any Australian state. Get this right before starting any work.

Do You Need a Permit for a Retaining Wall in Western Australia?

Name: Retaining Walls Direct
Address: 1 Pillapai Street, Charlestown, NSW, 2290, AU
Telephone: 1800 880 124
Price range: $$

Western Australia has the strictest retaining wall threshold in Australia — any wall over 500mm in retained height may require Development Approval. This catches walls that would be fully exempt in every other state. Confirm with your local council before starting any work.

Key note: The 500mm threshold is measured from finished ground level on the low side of the wall — not total wall height. Even modest-looking walls can trigger approval in WA.

WA Thresholds at a Glance

Condition	Approval required?
Under 500mm retained height, adequate boundary setback	Generally no — confirm with your council
Over 500mm retained height	Yes — Development Approval likely required
Within 1.0m of any property boundary	Yes — setback assessment required
Any driveway or vehicle parking above the wall	Yes — engineering mandatory at any height
Within a Special Control Area or heritage area	Yes — additional requirements apply

Development Approval in WA

Development Approval is assessed by your local council under the Planning and Development Act 2005. Use the My House WA portal (myhouse.wa.gov.au) to check your property zoning and R-codes before lodging. Timeframe: 4–8 weeks. Fees: $500–$1,500 in most council areas.

Perth Soil Conditions

Swan Coastal Plain (Joondalup to Rockingham): Sandy, Class A–S. Most straightforward for engineering. Standard 40MPa spec applies.
Perth limestone (Hills face zone and eastern suburbs): Variable. Rock boring costs $150–$350/hour. Get a geotechnical assessment before committing.
Sandy coastal dunes (western suburbs): Free-draining but loose; may require deeper post embedment.

Engineering Requirements in WA

Structural engineering under AS 4678:2002 is required for any wall over 1.0m and any driveway wall at any height. Given WA’s 500mm DA threshold, engineering is often required alongside the approval for walls in the 500mm–1.0m range. Engage the engineer before lodging the DA.

Perth Council Areas

Council area	Soil	Notes
City of Perth, Subiaco, Vincent	Sandy loam/limestone	Heritage areas in some precincts
Joondalup, Wanneroo, Swan	Sandy coastal	Standard 40MPa spec; straightforward engineering
Fremantle, Cockburn, Melville	Sandy with some clay near waterways	Good drainage; confirm stormwater outlet before starting
Kalamunda, Mundaring, Armadale	Limestone and granite	Rock boring risk; get geotechnical assessment
Rockingham, Mandurah	Sandy coastal	Standard conditions; 40MPa spec generally sufficient

Supplying Perth and all of Western Australia

Interstate freight quoted at checkout before you pay. Call 1800 880 124 for a formal materials quote.

Why is WA’s threshold lower than other states?

WA’s 500mm threshold reflects the WAPC’s conservative approach to retaining structures near boundaries. The rule is strict but clear: above 500mm, confirm with your council before starting.

How long does Development Approval take in WA?

4–8 weeks for a standard residential DA with complete documentation. Submit everything on first lodgement — requests for additional information restart the clock.

Does limestone affect post boring cost in Perth?

Significantly — Perth limestone can require specialist equipment adding $800–$3,000 per post hole in extreme cases. Always disclose limestone on site to contractors before accepting a quote.