Blue Mountains homeowners planning a retaining wall face one of the more confusing planning environments in NSW. The state’s Codes SEPP provides a standard framework for exempt and complying development, but the Blue Mountains City Council area overlays this with heritage conservation controls, World Heritage Area buffer provisions, bushfire-prone land rules and environmental zones that can change the applicable pathway for the same type of wall depending on exactly where your property sits.
This guide is a plain-language overview of the three consent pathways, exempt, complying development, and development application, and when each applies in the Blue Mountains context.
Quick answer (BLUF)
Walls under 600mm meeting standard Codes SEPP criteria are generally exempt (no consent needed), but in the Blue Mountains this exemption is removed for heritage conservation areas, WHA buffers, and sensitive environmental zones. Walls 600mm, 1,000mm may qualify for a complying development certificate (CDC), again subject to the same overlay exceptions. Walls over 1,000mm, or any wall in a heritage or sensitive area, require a full development application (DA). When in doubt, use BMaps and your planning certificate, not a neighbour’s advice.
Pathway 1: Exempt development, no consent required
Exempt development is building work that the law says doesn’t need council consent. For retaining walls, the standard exemption under the Codes SEPP requires:
Height: Not more than 600mm above natural ground level on the lower side
Location: Not in a heritage conservation area (HCA), draft HCA, or World Heritage Area buffer zone; not in a flood control lot, critical habitat, contaminated site, or within 40m of a classified watercourse
Boundary setback: Wall is not within the applicable setback of a neighbouring property or building boundary (specific distances vary)
Drainage: Wall must not redirect stormwater onto an adjoining property
Proximity: Not within 1 metre of a swimming pool or the footings of a building
If your wall meets all these criteria, you can build without any approval from BMCC. However:
- You are still responsible for building the wall correctly, exempt development is not an exemption from structural requirements; it is only an exemption from the consent process
- Heritage overlay properties are almost always removed from exempt status, check BMaps for every Blue Mountains property before assuming the exemption applies
Pathway 2: Complying development, fast-track approval
Complying development is work that meets specified criteria and can be approved by a private certifier (rather than going through council) in 10-20 days. For retaining walls, complying development under the Codes SEPP may apply for walls between 600mm and 1,000mm.
To qualify for complying development:
- The wall is not in a heritage conservation area or individually heritage-listed
- The site is not a flood control lot, critical habitat, WHA buffer zone or contaminated site
- The site is not in a coastal management area
- An engineer’s certificate is provided with the application
- The drainage management meets the specified criteria
For many Blue Mountains properties, particularly in Springwood, Lapstone, Blaxland and lower Lawson, this is a viable and much faster alternative to a full DA.
Pathway 3: Development application, full council assessment
A development application to BMCC is required when:
- Wall height exceeds 1,000mm and complying development is not available
- Property is in a heritage conservation area (regardless of height), this includes much of Katoomba, Leura, Blackheath, Wentworth Falls and Lawson
- Property is individually heritage-listed on the State Heritage Register or LEP schedule
- Wall is within 40 metres of a classified watercourse, very common in gully-side Blue Mountains properties
- World Heritage Area buffer zone applies
- Bushfire-prone land with wall heights or materials that don’t qualify for CDC
- Slope exceeds the DCP trigger threshold for slope-related controls
- Earthworks component exceeds thresholds, significant cut and fill associated with the wall
DA assessment by BMCC typically takes 40-80 working days. Supporting documentation varies by site, at minimum you need a site plan, engineer’s drawings and a statement of environmental effects. Heritage, biodiversity and drainage assessments may be additional requirements.
The heritage overlay: the most important Blue Mountains variable
The single most common reason a Blue Mountains retaining wall requires a DA when it wouldn’t elsewhere is heritage. BMCC’s heritage conservation areas cover large portions of the major Mountain towns and include a significant percentage of residential lots in Katoomba, Leura, Blackheath, Wentworth Falls, Lawson and Springwood.
If your property is in an HCA:
- The exempt development threshold effectively doesn’t apply
- A DA is required even for low walls that are visible from public land
- A heritage impact statement is required with the DA
- Materials must be consistent with the heritage character of the area
The 10 minutes it takes to check BMaps for your property before committing to a design is the most valuable planning step you can take.
Using the pre-lodgement meeting
BMCC offers free pre-lodgement meetings with their development assessment officers. For any retaining wall project where the consent pathway is unclear, or where the site has multiple overlays, this meeting is an excellent investment of time. The officer will:
- Confirm which consent pathway applies
- Identify any unusual requirements for your specific property
- Advise on the supporting documentation needed
- Potentially identify issues with a proposed design before it is finalised
Book through BMCC’s website or planning counter. It requires a brief project description and site address.
FAQs
Can my contractor apply for the DA on my behalf?
Yes. Either the property owner or the contractor (or a nominated agent such as a town planner) can lodge a DA on behalf of the applicant. The property owner is the applicant and bears ultimate responsibility for compliance.
If my wall qualifies for exempt development, can council still object?
BMCC cannot prevent exempt development, if the criteria are met, the work is lawful. However, if there is a question about whether the criteria are met (e.g., heritage overlay status is ambiguous), BMCC can investigate and issue a stop-work order if they believe development consent is required.
How do I confirm whether my property is in a heritage conservation area?
Check your Section 10.7 Planning Certificate (attached to your Certificate of Title or obtainable from BMCC) and overlay the heritage conservation area layer on BMaps. The DP and LEP schedule can also be checked, Heritage Conservation Areas are mapped in the BMCC LEP 2015 heritage maps.
What if I’m replacing an existing retaining wall in an HCA?
Demolition and rebuilding of an existing retaining wall in an HCA typically requires consent, even if the work is like-for-like. BMCC may treat it as a new wall proposal, a heritage impact statement will need to address the demolition of any heritage-era wall as well as the new construction.