Updated October 2026
Mundaring is the Shire's main town, strung along Great Eastern Highway on the plateau, and the Shire's own strategy describes its aim of keeping the hills as a series of discreet villages separated by rural buffers. Blocks here range from town lots to rural residential. We connect you with retaining wall builders who cover the 6073 area.
Common wall situations in Mundaring
The jobs split by block type. Town lots want terracing, driveway edges and replacement of walls built decades ago without drainage. Rural residential blocks want driveway cuttings, shed pads and batters. The Shire's standing planning policy is to maintain rural residential zoning over steep, well vegetated sloping land to limit erosion, which tells you what the ground is doing.
Mundaring is also the one sewered part of the Shire's hills. The Shire's strategy records that in the hills portion of the Shire only the Mundaring town centre has access to reticulated sewerage, and that it is likely most of the Shire will not be able to connect. If you are outside the town centre, the property's own system is part of your site plan.
The ground under Mundaring
Perth is a sand city. Up here it is not. The ground is ironstone and laterite gravel over weathered granite, and the City of Kalamunda records in its Local Planning Strategy that reticulated sewerage is constrained in the Hills because hard granite sits close to the surface and is costly to dig through. That same rock is what a post hole has to get through, so ask any builder how the quote prices a hole that hits it.
Drainage is the thing that actually matters. Water that cannot soak away through rock travels sideways and arrives behind the wall, and the Shire of Mundaring names heavy soils and perched water tables as Hills constraints for that reason. Ag-pipe, free draining gravel, geotextile fabric and a lawful discharge point are not optional line items.
The Shire of Mundaring also records that much of the Darling Range within its district is gazetted public water supply catchment, taking in the Mundaring Weir, Lower Helena, Victoria Reservoir and Kangaroo Gully catchments. In a catchment, earthworks and drainage carry closer scrutiny, and your builder confirms the position before the wall is designed.
What a wall costs in Mundaring
As a rough guide, most residential walls run from around $200 to $700 or more per metre for a wall about a metre high, depending on material, height, access and engineering. Those are published Australian guide figures rather than a quote, and rock is the reason a Hills number can sit above them. Read the retaining wall cost guide and then get a price for your block.
Approval, and who to ask in Mundaring
In WA a retaining wall is exempt from needing a building permit only where it retains no more than 500mm of ground, is not tied to other building work or to holding up the land next door, and is not work of a kind that affects adjoining land. The measurement is the ground the wall retains, not the height of the wall, which catches a lot of people out. All three conditions have to be met, so a wall on or near a boundary needs a permit whatever its height. Development approval under the local planning scheme can be a separate question again, and the rules change, so confirm your wall with the Shire of Mundaring before you build.
Who is allowed to build it is a statutory question in WA, and it turns on how the work is classified under the building legislation rather than on a figure you can look up and apply yourself. We are not going to settle that on a web page. What is worth doing is simple: ask the builder what registration or licence they hold, check it with Building and Energy, and ask your permit authority what your particular wall requires before you sign anything. Before any digging, your builder should lodge a free Before You Dig Australia (BYDA) enquiry so underground services are located.
Frequently asked questions
Is Mundaring on sewer?
The town centre is. The Shire of Mundaring's strategy records that in the hills portion of the Shire only the Mundaring town centre has access to reticulated sewerage, and that most of the Shire is unlikely ever to connect. Outside the centre, plan on an on-site system.
Does a big rural block escape the permit rules?
Do not assume it does. The WA exemption turns on retained ground and the two conditions beside it, not on how big your block is. The Shire of Mundaring is the permit authority across the district, acreage included, so ask them about your wall.
Who do I ask about my wall?
The Shire of Mundaring, because the local government is the permit authority. They will tell you whether your wall needs a building permit, whether development approval applies, and what engineering they expect.
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We also cover nearby Sawyers Valley and Stoneville.