Retaining walls and site works

Before starting any retaining wall or site works project, there are specific approvals you'll need to secure. Find out about requirements and how to apply.

Definitions

Retaining wall: A retaining wall is a structure specifically designed to support soil on a slope that is steeper than the natural inclination of the land, preventing subsidence. Such walls become necessary in areas where the land's differing levels require support at angles beyond its natural capacity to sustain itself.
Development (Planning) Approval: This is the City’s approval of your project's design and location, ensuring it aligns with local zoning and planning rules. It's the essential first step for any new building or significant alteration on your property.
Building Permit: A formal permission from the City for the construction, extension, or major renovation of a building, ensuring safety and compliance with building codes.
R-Codes: R-Codes, formally known as State Planning Policy 7.3 - Residential Design Codes, are a set of regulations that govern residential development in Western Australia. They detail the minimum requirements for the design and assessment of residential properties, focussing on aspects like building size, open space, setbacks, and density to ensure sustainable and community-friendly development across various residential zones.

Responsibility for constructing a retaining wall

Responsibility for constructing a retaining wall falls to the party altering the land's natural slope, whether by excavation (cutting) or by adding to it (filling). In situations where both neighbours have modified the land's elevation, each is responsible for the construction and upkeep of the retaining wall proportional to their alterations.

It's important to note that a dividing fence does not qualify to retain soil.

Find out if you need planning approval and/or a building permit below and how to apply.

Retaining walls and site works on residential properties require a development (planning) application unless they comply with the Residential Design Codes (R-Codes), the City’s Residential Development Local Planning Policy, the Development in Housing Opportunity Areas Local Planning Policy (HOALPP), or an applicable structure plan.

Single houses or grouped dwellings

Development (Planning) Approval is not required if your retaining walls and site works meet the following criteria:

Retaining, fill, or excavation between the street boundary and setback does not exceed maximum heights per your R-Code density.
Retaining and fill behind the street setback meet specified height and setback requirements.
There are no restrictions on excavation and associated retaining behind the street setback.

Additional requirements that may apply include:

Screening privacy: If retaining and fill exceeding 0.5m are within 7.5m of a side or rear boundary without existing screening, additional measures are required. Screening should be 1.6m above the finished ground level, made of durable material, and permanently affixed to prevent overlooking into neighbouring properties.
Street walls or fences: Refer to Fencing and Street Walls page.
Structure Plan areas: Properties within a structure plan area may be subject to further requirements.

Not sure of your R-Code or if your property is in a structure plan area? Insert your address into our online mapping system to view the R-Code and structure plan details. Contact the City of you need assistance.

Table 1: Retaining wall setback requirements based on R-Code density

Please note: For dual-density codes, if the property is not developed to the higher density, adhere to the R20 setback requirements.

R-Code Density	Street Setback	Maximum Height of Retaining Walls, Excavation and/or Fill in the Street Setback
R20	Street the house faces: 6m, or the setback between the street and house whichever is the lesser. Other streets (corner property): 1.5m	1m Any retaining and fill within 1.5m of where a driveway meets the street boundary shall be a maximum height of 0.75m.
R20/25	Street the house faces: 4m Other streets (corner property): 2m	0.5m
R20/30	Street the house faces: 4m Other streets (corner property): 2m	0.5m
R20/40	Street the house faces: 4m Other streets (corner property): 2m	0.5m
R20/60	Street the house faces: 2m Other streets (corner property): 2m	0.5m

Table 2: Height from Natural Ground Level – 3m+

Height from Natural Ground Level	Minimum Setback to a Property Boundary
0.5m or less	0m
1m	1m
1.5m	1.5m
2m	2m
2.5m	2.5m
3m	3m

Guidelines for building and maintaining retaining walls

Location of retaining walls

Retaining walls should ideally be constructed within the property boundaries where the works are proposed. Construction across property boundaries is permitted only with written agreement from all affected neighbours.

In instances where a retaining wall extends beyond the property boundary, a Notice and request for consent to encroach or adversely affect (BA20 form) is required. This form must accompany the building permit application. Additionally, Planning (Development) Application forms, where applicable, must be signed by both landowners involved.

Positioning of dividing fences near retaining walls

A dividing fence is to be positioned on the higher ground of a retaining wall which abuts a common boundary.

Privacy and overlooking

To safeguard privacy and prevent overlooking into adjoining properties, a fence measuring 1.8 metres in height is permitted atop a retaining wall. This applies when the wall:

Exceeds 0.5m in height
Is situated outside the front setback area of a property.
For fencing within the front setback area, adherence to the R-Codes' requirements for front fencing is mandatory. For more information refer to Fences and Street Walls.

Maintaining retaining walls

Owners are responsible for ensuring their retaining walls remain structurally sound. Should the City deem a retaining wall structurally inadequate, the owner must engage a practising structural engineer to assess the situation. Based on this assessment, the engineer will determine the necessary actions, if any, to restore the wall's structural integrity. The cost of consulting a structural engineer falls solely on the owner.

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Retaining walls and site works

Definitions

Responsibility for constructing a retaining wall

How to apply

Single houses or grouped dwellings

Table 1: Retaining wall setback requirements based on R-Code density

Table 2: Height from Natural Ground Level – 3m+

Guidelines for building and maintaining retaining walls

Location of retaining walls

Positioning of dividing fences near retaining walls

Privacy and overlooking

Maintaining retaining walls

Retaining wall disputes

Steps to resolving disputes

When land alterations impact dividing fences

Mediation for unresolved disputes

More information and contact

Retaining walls and site works

Definitions

Responsibility for constructing a retaining wall

How to apply

Step 1: Determine if Development (Planning) Approval is required open accordion

Single houses or grouped dwellings

Table 1: Retaining wall setback requirements based on R-Code density

Table 2: Height from Natural Ground Level – 3m+

Step 2: Apply for Development (Planning) Approval if required open accordion

Step 3: Determine if a Building Permit is required open accordion

Step 4: Apply for a Building Permit if required open accordion

Guidelines for building and maintaining retaining walls

Location of retaining walls

Positioning of dividing fences near retaining walls

Privacy and overlooking

Maintaining retaining walls

Retaining wall disputes

Steps to resolving disputes

Step 1: Understand the current ground levels open accordion

Step 2: Compare ground levels open accordion

Step 3: Reach an agreement open accordion

Step 4: Approval and permits open accordion

When land alterations impact dividing fences

Mediation for unresolved disputes

More information and contact