Plan Change 120: What has immediate legal effect – Natural Hazards & Flood Risk

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Auckland Council’s Plan Change 120 (PC120) signals a major shift in how natural hazard risks, particularly flooding, are managed across the region. 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.

For landowners, developers, and anyone preparing a resource consent application, this means that the new risk-based framework applies now, not later when PC120 becomes fully operative.

At Buckton Surveyors and Planners, we’ve broken down what this means in practice, what rules already apply, and how to navigate the transition.

Why immediate legal effect?

Under the RMA, some proposed plan rules take effect as soon as they are notified—specifically those that relate to the management of natural hazards. PC120 rewrites the entire E36 chapter, so the new objectives, policies, activity sensitivities, and hazard classifications are immediately relevant for all consent applications involving flood-prone land.

This includes information requirements, risk assessment obligations, and new decision-making policies.

What has immediate legal effect under PC120?

New risk-based framework (immediate effect)

PC120 shifts E36 away from assessing hazard presence to assessing risk. This framework is already active and must be considered in any resource consent.

Immediate-effect components include:

• Four flood hazard categories (Very High, High, Medium, Low) – defined in Chapter J. These replace the older, more general “flood plain” and “overland flow path” terminology.

• Three activity sensitivity groupings:

  o   Sensitive (e.g. dwellings, hospitals, marae)

  o   Potentially sensitive (e.g. schools, offices, retail)

  o   Less sensitive (e.g. carparks, open space, most rural activities)

• Risk matrices that combine hazard category + activity sensitivity.

• The requirement to avoid significant risk and mitigate where risk is potentially tolerable.

  
  

These concepts guide Council decision-making today.

Updated objectives and policies (immediate effect)

Because they relate to natural hazard management, all revised E36 objectives and policies apply immediately.

This includes the new policy direction to:

• Avoid development in areas where flood risk is significant.

• Ensure activities are compatible with the expected level of flood hazard.

• Consider depth, velocity, likelihood, and climate change impacts when assessing flooding.

• Prioritise nature-based mitigation before hard-engineering solutions.

• Distinguish between urban and non-urban contexts when assessing risk.

  
  

If you are preparing an Assessment of Environmental Effects now, these updated objectives and policies must be addressed.

Climate change requirements (immediate effect)

Climate resilience requirements also have immediate legal effect, including:

• Consideration of more intense rainfall and more frequent extreme events.

• Assessment of long-term risk exposure for all activity types.

• Demonstrating that development remains resilient over its design life.

This aligns with central government guidance and Council’s risk-avoidance approach for natural hazards.

Information requirements for flood-risk assessments (immediate effect)

Applications in flood hazard areas must demonstrate how design and mitigation measures address specific risk.

They must:

• Provide sufficient information to characterise hazard levels (depth, velocity, frequency).

• Demonstrate how design measures address the specific risk to people and property.

• Include climate change overlays using Council-approved methodologies.

• Show how development avoids or mitigates significant or potentially tolerable risk classifications.

For many sites, this will require specialist flood modelling or a risk assessment prepared by a suitably qualified expert.

Activity rules relating to natural hazards (immediate effect where they reduce risk)

Some PC120 activity rules relating to avoiding or mitigating natural hazard risk also gain immediate effect where they are more stringent.

This typically includes:

• Provisions controlling new buildings or earthworks in Very High or High flood hazard areas.

• Development triggers for risk assessment reports.

• Activity restrictions where sensitive uses are proposed in higher flood hazard categories.

What this means for your project

You may need additional technical reporting.

Even if your proposal previously required only a simple flood-plain check, the new framework may require:

• A flood risk assessment

• Revised building platform design

• Hydrological modelling

• Climate-resilient design considerations

Expect greater scrutiny of “sensitive” activities

Dwelling consents, visitor accommodation, education facilities, care facilities, and other vulnerable activities face a higher bar under PC120.

Non-urban sites face stronger avoidance requirements

PC120 directs new non-urban development away from areas where significant risk is present. This includes rural and Countryside Living land that contains overland flow paths or floodplains.

Existing development is treated differently

PC120 recognises that you can’t always move an existing house. Adaptation pathways, such as raising floor levels, reducing intensity, or shifting structures within a site, are encouraged.

How Buckton can help

At Buckton Surveyors and Planners, we work daily with subdivision, land-use, and infrastructure projects throughout Rodney and the wider Auckland region.

Our team can help you understand:

• Whether PC120 affects your site

• What hazard category applies

• Whether your activity is considered sensitive or less sensitive

• Whether a flood-risk assessment is required

• How best to design a compliant and resilient development

• How to structure your resource consent application to address the new objectives, policies and risk matrix.

  
  

Getting early advice can help you avoid costly redesigns or delays later in the process.

Make a submission on PC120

You have until 19 December 2025 to lodge a submission. See our previous Blog Have your Say on PC 120 for more information.

We can help you:

• identify the parts of PC120 that affect you

• frame your reasons

• prepare a clear, effective submission

Submissions can be simple and broad at this stage, details can be refined later.

Need advice on PC120 or Natural Hazard Risk?

If you’re unsure how the new rules affect your property, or you’re preparing a consent involving flood hazards, we’re here to help.

Get in touch with Buckton Surveyors and Planners for practical, tailored advice.

Contact the team