PC120 and Landslide Hazard Risk: What homeowners need to know for new builds and renovations in Auckland
- admin529303
- Dec 3, 2025
- 4 min read
We're so glad you're here - happy reading!
Got questions? Don't hesitate to get in touch
Auckland Council’s Proposed Plan Change 120 – Housing Intensification & Resilience (PC120) marks one of the most significant shifts in natural hazard management since the Auckland Unitary Plan (AUP) became operative. While 2023’s storms placed a spotlight on flooding, landslide risk is equally central to the new framework, especially for properties located on sloping ground, cliff edges, coastal bluffs, or hill-country suburbs.
From 3 November 2025, several components of the rewritten E36 Natural Hazards and Flooding chapter gained immediate legal effect under section 86B of the RMA. If you’re planning a new home, a dwelling replacement, or even a renovation involving earthworks or additions, PC120 may significantly change what you need to provide with your building or resource consent, and it’s operative now.
This blog outlines what PC120 proposes, why landslide risk is now treated differently, and what homeowners, developers and designers should expect.
Why PC120 changes landslide hazard management
PC120 introduces a new region-wide risk framework that assesses natural hazards, including landslides, based on:
Likelihood of the hazard occurring, and
Consequences of the hazard for people, property and infrastructure.
This replaces the older, simpler “avoid/not increase risk” approach in the AUP.
Auckland Council’s aim is to use the best available data to guide where development can safely occur, particularly following the landslides during the 2023 storms.
Updated mapping and definitions
PC120 strengthens how landslide-prone areas are identified. This includes:
New and updated landslide susceptibility mapping
Clearer identification of medium and high susceptibility areas
Integration of deep-seated and shallow landslide hazard layers
Stronger links between mapping and the rules in E36 Natural Hazards
This means many sloping or hillside properties, some of which previously had no hazard annotations on LIMs, may now be captured by the new rules.
NEW: Appendix 24 Landslide risk assessment methodology
PC120 introduces Appendix 24 – Landslide Hazard Risk Assessment Methodology, which sets out exactly how geotechnical specialists must assess landslide risk for development. This method is now the mandatory approach for new dwellings, major renovations, subdivisions and even some infrastructure on sloping sites. It requires a structured assessment of the likelihood and consequences of slope failure, and the outcome directly determines whether consent is straightforward, requires careful mitigation, or may not be possible.
Homeowners should be aware that geotechnical reporting will become more detailed and may be required for projects that previously did not trigger a full hazard assessment.
How landslide risk affects development
New Builds: Expect mandatory geotechnical hazard assessments
Under PC120, any new dwelling proposed within mapped medium or high landslide susceptibility areas will require a Landslide Hazard Risk Assessment prepared by a suitably qualified and experienced practitioner (SQEP).
Geotechnical reports will now need to:
Confirm whether a building platform is safe and stable
Demonstrate how the design either avoids or reduces landslide risk
Address “cascading hazards” (e.g., stormwater runoff triggering slope movement)
Show that risk is reduced to a “tolerable or acceptable” level under PC120’s new framework.
If risk is high, the default policy direction is to avoid development.
Renovations & alterations
Even modest renovations may now require specialist landslide assessment if:
Earthworks are proposed near a slope
Additions alter loading on a slope
Retaining walls, pools or excavation are involved
The property lies in a “run-out zone” downslope of a mapped susceptibility area
If permitted activity standards are not met, consent becomes restricted discretionary, with landslide risk the key matter of discretion.
3. Subdivision & boundary adjustments
Subdivision rules now require that:
Building platforms must be located outside high-risk areas
Access and private services must also be located safely
New lots must be able to achieve acceptable or tolerable landslide risk
This may limit infill development or require alternative layouts for sloping sites.
PC120 also updates the Special Information Requirements for subdivision. These now require:
Geotechnical risk assessments using Appendix 24 methodology
Consideration of slope stability, run-out, drainage and infrastructure vulnerability
Full assessment of consequences—not simply slope stability certification
Without these inputs, Council will not approve new lots or building platforms.
What this means for homeowners and developers
If you’re planning a new home:
Budget for a detailed geotechnical assessment early.
Design may need to adapt to avoid higher-risk areas on the site.
If you’re renovating:
Earthworks, pools, garages, decks and additions may now trigger landslide assessment.
Sites in run-out zones may face the same requirements as those on steep slopes.
If you’re subdividing:
New building platforms must be future proofed against risk.
High-risk locations may reduce yield or prevent subdivision.
If you’re rebuilding after storm damage:
Expect more rigorous geotechnical requirements before consent is granted.
How Buckton Surveyors & Planners can help
Our planning and surveying team works closely with geotechnical specialists to help clients navigate the new PC120 framework. We can:
Check your site against PC120 hazard layers
Coordinate geotechnical investigations
Prepare planning and subdivision applications that respond to the new risk-based rules
Design subdivision layouts that avoid high-risk areas
Provide a complete resource consent package for Council
We have also created a handy checklist which you can download here and check to see how your property may be affected.
If you’d like tailored advice on how PC120 affects your property, or whether your site is captured by the new landslide hazard provisions, contact our planning team today.