Answer first: Under Chapter 4 of State Environmental Planning Policy (Resilience and Hazards) 2021, a consent authority must not consent to development unless it has considered whether the land is contaminated and, if it is, is satisfied the land is suitable in its contaminated state (or will be suitable after remediation) for the proposed purpose. Where remediation is required, the consent authority must also be satisfied remediation will occur before that use. For many change-of-use DAs on land with a potentially contaminating history, clause 4.6 also requires a preliminary investigation report prepared in accordance with the contaminated land planning guidelines.
Author: Franz Phan, Senior Planning Consultant, giantA Pty Ltd · Updated 14 September 2026
What does SEPP (Resilience and Hazards) Chapter 4 actually do?
Former SEPP 55 — Remediation of Land is now Chapter 4 — Remediation of land in State Environmental Planning Policy (Resilience and Hazards) 2021. NSW Planning confirms the same statewide framework still guides how contamination is considered in rezoning and development decisions, alongside the EPA’s Managing Land Contamination: Planning Guidelines.
Chapter 4’s object is a statewide planning approach to remediation that reduces risk of harm to human health or the environment by:
- specifying when consent is required for remediation work
- setting contamination considerations for rezoning and DAs
- requiring remediation work to meet standards and notification requirements
Sources: NSW Planning — Contaminated lands · EPA — Role of planning authorities.
What must a consent authority decide under clause 4.6?
Clause 4.6 is the DA workhorse. A consent authority must not consent to development on land unless:
- it has considered whether the land is contaminated
- if the land is contaminated, it is satisfied the land is suitable in its contaminated state (or will be suitable after remediation) for the proposed purpose
- if remediation is needed to make the land suitable, it is satisfied the land will be remediated before that use begins
This is a suitability test for the proposed use, not a free-standing “clean to residential standards” rule for every project. A warehouse reuse, a childcare centre and a dwelling house sit on different exposure pathways — and councils expect the investigation scope to match the sensitivity of the end use.
Source: SEPP (Resilience and Hazards) 2021 — clause 4.6.
When is a Preliminary Site Investigation (PSI) mandatory for a DA?
Clause 4.6(2)–(3) require the applicant to prepare, and the consent authority to consider, a preliminary investigation report (in practice, a Preliminary Site Investigation / PSI) before determining a DA that involves a change of use on land listed in clause 4.6(4). That land includes:
- land within an investigation area under the Contaminated Land Management Act 1997
- land on which a Table 1 potentially contaminating activity (from the contaminated land planning guidelines) is being, or is known to have been, carried out
- for proposed residential, educational, recreational, childcare or hospital uses — land where knowledge of past Table 1 activities is absent or incomplete, and such activities would have been lawful during the unknown period
If the PSI findings warrant it, the consent authority may require a detailed investigation (Detailed Site Investigation / DSI) consistent with the same guidelines.
Practical giantA reading for designers: a knockdown-rebuild to a dwelling, a warehouse-to-apartment conversion, or a site with former workshop, service-station, landfill, market-garden or industrial use history is where PSI risk spikes — even when the current zoning looks “clean”.
PSI vs geotech soil testing — what is the difference?
| Report | Primary question | Typical trigger |
|---|---|---|
| Preliminary / detailed site investigation (contamination) | Is the land contaminated, and is it suitable for the proposed use (with or without remediation)? | SEPP Resilience and Hazards cl 4.6; council contaminated-land policy; change of use / sensitive use |
| Geotechnical investigation / site classification | How will the ground behave for foundations and earthworks (e.g. AS 2870 class)? | Structural design, slab/footing selection, earthworks methodology |
Both may involve drilling and sampling, but they answer different statutory questions. Do not assume a geotech borehole log substitutes for a contamination PSI. For foundation-focused testing, see giantA’s Soil testing and geotechnical investigation NSW 2026.
How do section 10.7 certificates fit the contamination picture?
Councils must record prescribed Contaminated Land Management Act matters on section 10.7(2) planning certificates (for example significant contamination declarations, management orders, voluntary management proposals, ongoing maintenance orders and site audit statements held). Section 10.7(5) certificates can carry additional council-held contamination information.
A clean-looking 10.7(2) certificate is not a warranty that no contamination exists. It mainly surfaces EPA-regulated status and prescribed notations. Due diligence still needs site history, aerials, council records and, where cl 4.6 applies, a proper PSI.
See also: Section 10.7 planning certificates NSW 2026 · EPA guidance on planning authorities and certificates.
Category 1 vs Category 2 remediation — when is DA consent required?
Chapter 4 makes remediation work permissible despite conflicting EPI provisions (subject to the Chapter’s limits) and then splits remediation into:
- Category 1 remediation work — needs development consent (section 4.8)
- Category 2 remediation work — may proceed without consent (section 4.11), still subject to notification and work standards in the Chapter
Category 1 captures higher-risk scenarios (including designated development and remediation on certain sensitive or critical land — always read the full section 4.8 list for the current instrument text). Category 2 is the residual class that is not Category 1.
Do not self-classify remediation from a marketing brochure. Contaminated-land consultants and, where required, site auditors frame the Remedial Action Plan (RAP), validation and any site audit statement the consent authority needs to reach the clause 4.6 satisfaction tests.
Source: SEPP (Resilience and Hazards) 2021 — sections 4.7–4.11.
What documentation sequence works for a NSW residential or mixed-use DA?
- Pull the section 10.7 certificate early — both (2) and, where risk warrants, (5).
- Rebuild site history — titles, aerial photography, council files, EPA List of Notified Sites / Record of Notices checks, and any known workshop, fuel, orchard, landfill or industrial uses.
- Decide whether cl 4.6(2) is triggered — change of use + clause 4.6(4) land categories.
- Commission a PSI to the contaminated land planning guidelines / NEPM assessment framework used by competent consultants — not a one-page “visual only” note unless the guidelines genuinely support that scope.
- Escalate to DSI / RAP / validation only when findings require it; keep design options flexible until suitability is clear.
- Coordinate architecture with remediation constraints — slab levels, basement extent, landscaping, OSD tanks and play areas often move when capping, excavation or validation sampling is required.
- Use pre-DA to confirm council’s contaminated-land policy expectations and whether a site audit will be conditioned. See Pre-DA meetings in NSW 2026.
- Keep pathway honesty — contamination issues are rarely solved by switching to CDC if the land fails SEPP suitability logic; start with Exempt vs CDC vs DA.
What site history red flags should architects and owners watch for?
- Former service stations, mechanic workshops, dry cleaners, printeries or panel beaters
- Market gardens / orchards with historic pesticide or herbicide use
- Fill platforms, former tips, demolition rubble or asbestos-containing building fabric
- Rail corridors, timber treatment, metal finishing, foundries or gasworks legacy sites
- Incomplete knowledge on an older industrial or mixed-use lot proposed for housing, education or childcare
These map closely to the guideline Table 1 concept behind clause 4.6(4). They are risk signals for investigation scoping — not automatic proof of contamination.
How does EPA regulation differ from the planning pathway?
The planning pathway (SEPP Chapter 4 + EP&A Act assessment) manages contamination through rezoning and DA suitability decisions for land that is not necessarily “significantly contaminated” under the Contaminated Land Management Act 1997. Separately, the EPA can declare and regulate significantly contaminated land under that Act. Both systems can touch the same lot, but a DA consultant report does not replace an EPA management order — and an absence of EPA notation does not remove clause 4.6 duties for the consent authority.
Frequently asked questions
Do I need a PSI for every house renovation DA?
Not automatically. Clause 4.6 always requires the consent authority to consider contamination, but the mandatory preliminary investigation report is tied to change-of-use proposals on the land categories in clause 4.6(4). Many alteration DAs still attract council requests where site history is uncertain or a sensitive use intensifies exposure. Check the council’s contaminated-land policy and DCP documentation schedule before assuming a waiver.
Can remediation be conditioned after DA approval?
Clause 4.6 requires the consent authority to be satisfied about suitability and, where needed, that remediation will occur before the land is used for the approved purpose. Councils commonly use staged conditions (RAP approval, validation, site audit) — but they still need enough investigation at determination to be lawfully satisfied. Lodging a DA with zero contamination information on a high-risk site usually produces requests for information, not a clever deferral.
Is SEPP 55 still the correct citation in 2026?
Use SEPP (Resilience and Hazards) 2021 Chapter 4. SEPP 55’s remediation framework was consolidated into that Chapter. Older reports may still say “SEPP 55”; translate them to the current instrument when you write new SEE / planning statements.
Who should prepare the PSI?
A suitably qualified contaminated-land consultant following the contaminated land planning guidelines and current EPA reporting expectations. Architects coordinate; they should not author contamination conclusions outside their competence.
Does flood or bushfire mapping remove contamination duties?
No. Other hazard layers (for example flood planning levels) are additional considerations. Contamination remains a separate Chapter 4 / clause 4.6 question.
Key takeaways for NSW DA teams in 2026
- Cite SEPP (Resilience and Hazards) 2021 Chapter 4, not retired SEPP 55 branding, in fresh documentation.
- Clause 4.6 is a hard consent precondition: consider contamination, confirm suitability, and lock in remediation timing where required.
- Change-of-use proposals on clause 4.6(4) land need a guidelines-compliant preliminary investigation — budget and programme it before design freeze.
- Section 10.7 certificates are necessary due diligence, not a substitute for site history or a PSI.
- Remediation consent depends on Category 1 vs Category 2 classification under the Chapter — get specialist advice early.
If you are scoping a knockdown-rebuild, warehouse conversion or sensitive-use DA and need the architectural package coordinated with contamination constraints, giantA can help structure the DA pathway and consultant brief around clause 4.6 — without pretending a drawing set replaces a PSI.