Retaining Wall Permits and Rules in WA

This guide explains, in plain English, when a retaining wall in Perth or Peel needs approval. It is general information, not legal advice. Rules change and every council has its own process, so always confirm with your local government before you build. Your local specialist can also advise on what your wall is likely to need.

Limestone block retaining wall with palms in coastal Western Australia

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The 0.5 m rule: when you don’t need a building permit

Under the Building Regulations 2012 (WA), Schedule 4, a retaining wall does not need a building permit only if all of these apply:

  • it retains ground no more than 0.5 m in height; and
  • it is not associated with other building work or with protecting land next door; and
  • it is not work covered by sections 76 to 79 of the Building Act 2011 (encroaching onto, or adversely affecting, neighbouring land, protecting structures beyond the boundary, or party walls).

If any one of those fails, you need a building permit. So a 0.6 m garden wall, a low wall supporting a new patio, or a low wall that changes drainage onto the neighbour’s lot can all need one.

Building permit vs planning (development) approval

These are two different things. A building permit is about structural safety and is issued by the council’s permit authority. Development (planning) approval is about where and how high the wall and fill sit. Where planning approval is needed, it must usually come first.

For houses, the R-Codes (State Planning Policy 7.3, Volume 1, clause 5.3.7) set the deemed-to-comply rules. If your wall meets them (and any local policy or structure plan), you generally don’t need planning approval:

  • Between the street boundary and the street setback (the front yard), retaining, fill and excavation not more than 0.5 m above or below natural ground level, except for access, drainage or light.
  • Behind the street setback, setbacks from the lot boundary per Table 4: 0.5 m or less, 0 m setback; 1 m high, 1 m; 1.5 m, 1.5 m; 2 m, 2 m; 2.5 m, 2.5 m; 3 m, 3 m (take the nearest higher value, measured from natural ground at the boundary).
  • Within 1 m of a lot boundary, fill no more than 0.5 m above natural ground level at the boundary, unless a scheme, policy, structure plan or local development plan says otherwise.

Many new estates have local development plans (LDPs) with their own retaining rules. Check yours.

Engineers

Walls needing a permit are typically lodged with an engineer’s design, and several councils require engineering generally. The City of Fremantle says all retaining walls regardless of height must be designed by a practising structural engineer; the City of Kalamunda’s policy says all retaining walls must be designed by a suitably qualified structural engineer; the City of Rockingham says a practising structural engineer may be required to certify the wall.

Boundaries, neighbours and the Dividing Fences Act

  • Who builds it: generally the owner who changes the lie of the land (cut or fill) is responsible for retaining it (Legal Aid WA; City of South Perth).
  • Both changed levels: each owner is responsible to the extent of their own alteration (City of Kwinana; City of South Perth). A licensed surveyor may be needed to work out original levels.
  • Repairs to a shared boundary wall: under Building Act 2011 s89, unless otherwise agreed, owners on each side of a boundary retaining wall that is wholly or partly on the boundary contribute equally to maintenance and repair.
  • Dividing Fences Act 1961: covers dividing fences, not retaining walls. A dividing fence is not considered suitable for retaining soil (City of South Perth). The fence on top is a separate matter under the Act.
  • Encroachment: walls and footings should generally sit wholly within the lot. Encroaching requires the neighbour’s written consent, usually using form BA20 (Notice and request for consent to encroach or adversely affect); affected owners have 28 days to consider it.

Council-by-council notes

Summarised from each council’s published information as at October 2026. Always check the current page.

City of Rockingham (Baldivis, Rockingham, Port Kennedy, Secret Harbour)

All retaining walls greater than 500 mm need a building permit before work starts. Walls under 500 mm also need one if they encroach, reduce the bearing capacity of adjoining land, damage structures, or change natural site drainage. Walls should be built wholly within the lot, and boundary walls should be designed around the fence planned on top.

City of Wanneroo (Wanneroo, Clarkson, Alkimos, Yanchep and more)

A building permit is required where a wall exceeds 500 mm, is an addition to an existing wall, or tiered walls exceed 500 mm in total height. Planning approval is required in the Residential zone where walls don’t comply with the R-Codes, and in any other zone; it must be obtained before a building permit is issued.

City of Joondalup

No building permit is needed only where the wall is 0.5 m or less, isn’t part of or doesn’t require building work to protect adjoining land, and doesn’t adversely affect neighbours. Planning approval is needed unless walls comply with the R-Codes and City policies. Certified (BA1 + BA3) and uncertified (BA2) permit applications are accepted. (BA1, BA2, BA3 and BA20 are the Building Commissioner’s approved forms, published by Building and Energy on wa.gov.au.)

City of Kwinana

A building permit is needed for any wall 500 mm or greater; the City’s note also says planning approval is required for a total change of 500 mm or more above natural ground level. Walls on or next to a boundary must be masonry (brick, limestone or granite block, or concrete post and panel); timber sleepers, metal sheeting and fibre-cement won’t be approved there.

City of Mandurah

The City’s retaining walls information sheet (2022) says a “minor” wall not exceeding 0.5 m generally doesn’t need a building permit, excluding additions that increase the retained height. Walls higher than 0.5 m need a building permit and in some instances planning approval. Walls that raise ground levels by more than 0.5 m will generally need planning approval, usually with consultation of affected neighbours. Canal-front lots have their own retaining rules under the City’s Local Planning Policy No. 1, so check with the City before working near a canal wall.

Shire of Serpentine Jarrahdale (Byford, Mundijong)

All retaining walls greater than 500 mm high need a building permit before work starts. Walls under 500 mm also need one if they encroach, reduce the bearing capacity of adjoining land, damage structures, or change natural site drainage. Planning approval is needed where a wall exceeds 500 mm and doesn’t meet the R-Code side and rear setbacks, or exceeds 500 mm within the front setback. Walls must be built entirely within one property and are not permitted to straddle the boundary, and a fence must not be used to retain soil unless designed to do so.

City of Armadale

The City’s retaining wall information sheet (February 2025) says a building permit is required for walls over 0.5 m, and that a wall built on the boundary between properties may need a building permit regardless of height. Walls must be set back per the R-Codes, planning approval may be needed before a permit can be issued, and the application checklist includes a structural engineer’s certification.

City of Swan (Ellenbrook)

The City of Swan treats retaining walls as Class 10b structures: check the City’s exemption list first, obtain any planning approval before applying, and lodge the building permit application online. Uncertified applications (form BA2) are assessed within up to 25 business days. Contact the City for site-specific requirements.

City of Gosnells and City of Canning (Canning Vale)

Canning Vale is split between the City of Canning (west of Nicholson Road) and the City of Gosnells (east). The City of Gosnells says a building permit is required for any wall retaining more than 0.5 m, and regardless of height where the wall is associated with other building work, encroaches, affects or protects adjoining land, or affects a party wall, substantial dividing fence or existing boundary retaining wall. Development approval may also be needed for walls over 0.5 m or less than 1.5 m from the boundary. The City of Canning publishes a Retaining Walls information sheet (BIS-10); contact its Building Services for current requirements.

Building without approval

Councils can require unapproved walls to be certified or removed, and an unapproved wall can cause problems when you sell. The City of Wanneroo, for example, has a separate unauthorised works process. It is much cheaper to do it right first time.

Call 0485 557 649 for a free, no-obligation quote from a local, insured Perth retaining wall specialist.

Sources

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