Remediation Action Plans and Site Audits in Australia

A remediation action plan (RAP) is the document that says how contaminated soil or groundwater on a site will be dealt with, to what standard, and how that will be proven afterwards. On a brownfield acquisition it is rarely the largest line in the budget, but it is very often the one that decides whether the deal proceeds at all, because in most states an independent auditor has to sign off on the outcome before the consent authority will let a sensitive use go ahead.

Before considering a remediation action plan (RAP) or a contaminated land site audit, you’ll need professional advice from an environmental lawyer, and from an environmental consultant who works in the relevant state. The reason is that the obligations here fall on you personally rather than on your consultant. Duties to notify the regulator attach to owners and occupiers, carry criminal penalties in several states, and can be triggered by what you “ought reasonably” to have known. A classification or an order can be registered against the title. Disclosure obligations on sale can hand a buyer a right to rescind. None of that sits with the consultant who wrote the report. This guide is written to make that conversation with your lawyer sharper, not to replace it, and there is a list of specific questions to take into it near the end.

Rules, section numbers and figures below were current at the time of writing in August 2026, and this area moves. Each state regulator and each Act is linked, and those are the places to confirm anything you are about to rely on.

What is a remediation action plan?

A remediation action plan (RAP) sets out the actions proposed to clean up or contain contamination on a site, the criteria the outcome will be measured against, and how compliance with those criteria will be validated. It is written by an environmental consultant, usually after a detailed site investigation has established what is present and where, and it generally has to be reviewed or approved before remediation works start.

The terminology varies. New South Wales planning law calls it a “plan of remediation”. Environment Protection Authority Victoria calls it a clean up plan, describing clean up plans as “also referred to as remediation action plans” in its guideline on creating a clean up plan for contaminated land, published 15 August 2025. Queensland folds the same function into a “draft site management plan” where contamination is being managed rather than removed. The document does the same job under each name.

What a remediation action plan (RAP) typically has to contain gives a fair sense of the work involved. Environment Protection Authority Victoria’s guideline lists fourteen content areas, including the conceptual site model, remaining data gaps, the remediation approach and the criteria to be met, risk management and contingency plans, an unexpected finds protocol, an environmental monitoring programme, validation of clean up activities, timeframes, and the permits and regulatory approvals needed.

For a developer the practical point is that a remediation action plan (RAP) is a construction document as much as an environmental one. It commits you to a method, a disposal route, a monitoring regime and a validation standard, and each of those has a price and a programme consequence.

What is a contaminated land site audit, and who can carry one out?

A contaminated land site audit is an independent review, by a person accredited or appointed by the state regulator, of the investigation and remediation work done by a consultant. The auditor does not do the investigation. The auditor forms an opinion on whether the work was adequate and whether the land is, or will be, suitable for a stated use.

The distinction matters commercially. Your consultant works for you. The auditor does not, even though you pay them. The NSW Environment Protection Authority describes accredited site auditors as people who “can be engaged to independently review contaminated land consultant reports”, and publishes the list of accredited site auditors. Environment Protection Authority Victoria puts it more bluntly, stating that it does not “recommend or engage environmental auditors” and does not “control the progress of PRSAs or environmental audits once they begin, as they are independent processes” on its page covering its role in the environmental audit system.

Accreditation is state by state. New South Wales accredits under Part 4 of the Contaminated Land Management Act 1997 (NSW). Victoria appoints environmental auditors under the Environment Protection Act 2017 (Vic). Queensland approves auditors under section 570 of the Environmental Protection Act 1994 (Qld), per its auditor applications page. Western Australia accredits under section 69 of the Contaminated Sites Act 2003 (WA), and South Australia under Division 4 of Part 10A of the Environment Protection Act 1993 (SA).

Tasmania and the Northern Territory do neither. Both recognise auditors accredited elsewhere. The Tasmanian Environment Protection Authority (EPA) states that persons on its Register of Contaminated Land Auditors “are accredited under interstate legislation, and have successfully applied to the EPA Director … to be included on the Register”. The Northern Territory Environment Protection Authority has approved persons accredited under the New South Wales, Victorian, South Australian, Western Australian and Queensland schemes “as a class of persons suitable to undertake Environmental Audits in the Northern Territory”, under section 68 of the Waste Management and Pollution Control Act 1998 (NT), per its register of qualified persons.

Two consequences follow for a developer. The pool of accredited people is small, which is a programme risk in itself. And an auditor engaged early tends to cost less than one engaged late, a point the Queensland Government makes directly on its auditor engagement page: “Auditors should be engaged at the beginning of the project to clarify the requirements. Early communication … will promote better outcomes and help avoid the potentially costly situation where works completed by a suitably qualified person are subsequently found by the auditor to be insufficient or inappropriate.”

How does contamination assessment run, from preliminary site investigation to validation?

The sequence is generally preliminary site investigation, then detailed site investigation if warranted, then remediation action plan (RAP), then the works, then a validation report, and then an auditor’s statement on suitability. Each stage exists to decide whether the next one is needed.

The national methodology sits in the National Environment Protection (Assessment of Site Contamination) Measure 1999, made under the National Environment Protection Council Act 1994 (Cth). The National Environment Protection Council records that it was made on 10 December 1999, commenced 22 December 1999, and was varied on 11 April 2013, with the amendment taking effect “in each jurisdiction on 16 May 2013”. It is registered federally as F2008B00713. Schedule A sets out the staged assessment process and Schedule B carries the technical guidelines, of which Schedule B1 (investigation levels for soil and groundwater) is the one most often quoted at developers.

The Measure states its own purpose as being “to establish a nationally consistent approach to the assessment of site contamination to ensure sound environmental management practices by the community which includes regulators, site assessors, environmental auditors, land owners, developers and industry”. It is a methodology rather than a set of directly enforceable duties. Each jurisdiction gives it effect through its own legislation, and Tasmania goes furthest by giving it effect as a State Policy under section 12A of the State Policies and Projects Act 1993 (Tas).

A preliminary site investigation is largely a desktop and inspection exercise. The Measure describes it as usually involving establishing a site history, inspecting the site, and interviewing representatives for the site, with any sampling “confined to areas where potentially contaminating activities have occurred”. It should “be sufficient to identify whether contamination exists on the site”, and expressly notes that “contamination may not be completely delineated at this stage”.

A detailed site investigation is triggered where that is not enough. The Measure’s own language is worth quoting, because it is what your consultant will use back at you: “A detailed investigation is required when the results of preliminary investigation are insufficient to enable site management strategies to be devised.” Indicators it names include unexpected underground structures such as fuel or chemical storage tanks, imported fill such as ash or refuse, staining of soil, and contaminants above background levels or applicable investigation levels.

It also flags something that catches developers in their programme: “Many site investigations proceed in multiple stages due to the complexity of the site and the discovery of unexpected contamination, or as investigation funds become available.” A detailed site investigation is not necessarily one round of sampling.

A validation report follows the works and demonstrates that the criteria in the remediation action plan (RAP) were met. Where contamination is left in place, a long term environmental management plan usually goes with it, imposing ongoing obligations on whoever owns the land afterwards.

When does a site audit become compulsory?

Broadly, when a sensitive use is proposed on land with a contaminating history, or when the regulator requires one. The definition of “sensitive use” is narrower than developers often assume, and the definition of a contaminating history is broader.

Victoria’s definition is the tightest drafted. Environment Protection Authority Victoria states that “sensitive use means: residential use; a childcare centre; a kindergarten; a preschool centre or primary school”, on its page on assessing potentially contaminated land for land use planning. Planning Practice Note 30 adds the words that catch people: those uses count “even if ancillary to another use”. A caretaker’s dwelling over a workshop could bring the whole trigger into play. Children’s playgrounds and secondary schools sit outside the definition in Victoria but attract the same treatment under Ministerial Direction No. 1 and the Environmental Audit Overlay.

South Australia’s is similar but not identical, covering “a residential use (including all forms of residential use such as medium and high density developments and retirement villages), a pre-school (including a childcare centre) or a primary school”, per the South Australian Environment Protection Authority’s page on assessment and remediation.

The Assessment of Site Contamination Measure states the general principle that consent authorities “should ensure a site that is being considered for development or a change in land use, and that the authorities ought reasonably know if it has a history of use that is indicative of potential contamination, is suitable for its intended use”. Every state implements that idea through different machinery, and the machinery is what determines your programme.

New South Wales: how do the contaminated land and planning regimes work together?

New South Wales runs two parallel systems. The Contaminated Land Management Act 1997 (NSW) is the regulatory arm, and Chapter 4 of the State Environmental Planning Policy (Resilience and Hazards) 2021 is the planning arm. Most developers meet the planning arm first.

Chapter 4 is the former State Environmental Planning Policy No 55, as the NSW Department of Planning confirms. Its section 4.6(1) is the clause that decides development applications on contaminated land: “A consent authority must not consent to the carrying out of any development on land unless (a) it has considered whether the land is contaminated, and (b) if the land is contaminated, it is satisfied that the land is suitable in its contaminated state (or will be suitable, after remediation) for the purpose for which the development is proposed to be carried out, and (c) if the land requires remediation to be made suitable … it is satisfied that the land will be remediated before the land is used for that purpose.”

Section 4.6(2) makes a preliminary investigation report compulsory before a change of use application is determined on specified land, and section 4.6(3) allows the consent authority to escalate: it “may require the applicant to carry out, and provide a report on, a detailed investigation … if it considers that the findings of the preliminary investigation warrant such an investigation”. The specified land in section 4.6(4) includes land within a declared investigation area, land carrying a use in Table 1 to the contaminated land planning guidelines, and land proposed for residential, educational, recreational or child care purposes.

The remediation work itself is then split. Section 4.7 provides that category 1 remediation work needs development consent and category 2 does not. Section 4.8 defines category 1 by reference to designated development, critical habitat, threatened species impacts, and land in conservation, environment protection, floodway, coastal protection and similar classifications, and section 4.11 makes everything else category 2. Under section 4.13, category 2 work still requires written notice to council “at least 30 days before the commencement of the work” in the ordinary case.

Section 4.14(1)(c) is where the remediation action plan (RAP) appears in the legislation. For category 1 work, remediation must be carried out in accordance with “a plan of remediation, as approved by the consent authority, prepared in accordance with the contaminated land planning guidelines”. Section 4.14(2) then requires a notice of completion to council, and section 4.15 sets out what that notice must contain, including under paragraph (m) what “must be maintained in relation to the land after the completion of the remediation work if the standard of remediation achieved is to be maintained”. A note to section 4.15 records that “a site audit statement (within the meaning of Part 4 of the Contaminated Land Management Act 1997) may be given in partial compliance with this requirement”.

On the regulatory side, the Contaminated Land Management Act 1997 (NSW) gives the NSW Environment Protection Authority power under section 11 to declare land significantly contaminated, having considered the matters in section 12. A declaration can be followed by a management order under section 14, or by an ongoing maintenance order under section 28 where contamination is being managed in place rather than removed. Section 58 requires a public record and section 59 requires the regulator to give a copy to the local council, which must then note it on the planning certificate issued under section 10.7(2) of the Environmental Planning and Assessment Act 1979 (NSW). If you are buying, the section 10.7 planning certificate is where a declaration or an order will surface.

A duty to report contamination to the regulator sits in section 60 of the Act. The NSW Planning Portal’s contamination guidance refers to “the reporting of land contamination requirements now legally required under section 60 of the Act”. The trigger conditions are specific and worth having your lawyer read to you against the current text rather than paraphrased. Statutory guidelines made under section 105 bind auditors and consultants, and the sampling design guidelines took effect on gazettal on 12 August 2022.

Victoria: what does the preliminary risk screen assessment change?

Victoria added a cheaper front gate. Since the Environment Protection Act 2017 (Vic) commenced on 1 July 2021, a preliminary risk screen assessment (PRSA) can be used to establish that a full environmental audit is not required, which on a marginal site may save both time and money.

Under section 204, the purpose of a preliminary risk screen assessment (PRSA) is “to assess the likelihood of the presence of contaminated land and determine if an environmental audit is required and if an environmental audit is required, to recommend a scope for the environmental audit”. Only an appointed environmental auditor can prepare one. Environment Protection Authority Victoria sets out the three possible outcomes: contaminated land unlikely and no audit required; contaminated land likely but no audit required because there is no risk of harm given the proposed use; or contaminated land likely and an audit required. The outcome “is only valid for the proposed land use that the auditor has specified”.

Planning Practice Note 30 is direct about when to use which route. A preliminary risk screen assessment (PRSA) “is recommended for scenarios where it is uncertain whether an audit is warranted: specifically those with lower potential for contamination (in the medium category) or for sites where the proposal is relatively minor”. Where the site is in the high contamination category and a new sensitive use is proposed, the practice note says proceeding directly to audit “is likely to provide the most efficient outcome”. That is a genuinely useful signal for programming a Victorian acquisition.

The Environmental Audit Overlay at clause 45.03 of the Victoria Planning Provisions is the planning trigger. Land carrying the overlay cannot be used or developed for a sensitive use until one of four things happens: a preliminary risk screen assessment (PRSA) states an audit is not required; an environmental audit statement concludes the land is suitable; a certificate of environmental audit was issued under the Environment Protection Act 1970 (Vic); or a statement of environmental audit was issued under that older Act stating the conditions are suitable. Note that the older Act’s certificates and statements still count. Note also that the overlay bites whether or not a planning permit is otherwise needed.

The three outcomes of a suitability audit under section 208 are that the site is suitable for the specified purposes, suitable if the recommendations in the statement are complied with, or not suitable at the time the statement was prepared. Under section 210 the statement must go to the relevant planning and responsible authority within five business days of issue, and the person in management or control must also give a copy to anyone proposing to take over that role, which includes a prospective purchaser.

Outside the planning system, two duties run continuously and both attach to whoever holds the land. Section 39(1) imposes the duty to manage contaminated land: “A person in management or control of contaminated land must minimise risks of harm to human health and the environment from the contaminated land so far as reasonably practicable.” Section 40(1) imposes the duty to notify: “A person in management or control of land must notify the Authority if the land has been contaminated by notifiable contamination as soon as practicable after the person becomes aware of, or reasonably should have become aware of, the notifiable contamination.”

Two things about section 39 matter to a buyer. It applies regardless of fault, as Environment Protection Authority Victoria states plainly on its duty to manage page: “You have a duty to manage contamination on your land even if you did not cause the contamination.” And section 39(2)(e) requires you to give adequate information to anyone reasonably expected to take over management or control, which reaches into your sale process. Section 39(3) runs the other way, allowing recovery of reasonable compliance costs “against any person responsible for causing or contributing to contamination of the land”.

What counts as notifiable contamination is set by Part 2.1 of the Environment Protection Regulations 2021, and it is a substance, concentration and circumstance test rather than a cost threshold. Environment Protection Authority Victoria’s page on notifying contaminated land sets out each limb, including health investigation levels and health screening levels for soil and vapour, and for friable asbestos “airborne asbestos fibre levels in excess of 0.01 fibres/mL by means of inhalation”.

Queensland: what do the Environmental Management Register and the Contaminated Land Register do to a site?

Queensland runs two public registers, and being on the first one is far less serious than being on the second. The Queensland Government explains that land goes on the Environmental Management Register (EMR) if a notifiable activity has been or is being carried out on it, or if it is contaminated land, and that “when land is listed on the EMR for a notifiable activity, it is an indication that the land is likely to be contaminated but it does not mean it needs to be cleaned up or is not suitable for its current land use”.

Land moves to the Contaminated Land Register only “where it is necessary to take action to remediate the land to prevent serious environmental harm and protect human health or other aspects of the environment”. Listing follows a show cause notice, with 20 business days for the landowner to make a submission, and a decision notice issued within five business days, with a copy to any registered mortgagee where the listing is on the Contaminated Land Register.

Notification duties sit in section 320A of the Environmental Protection Act 1994 (Qld). The Queensland Government’s notifications page sets out two clocks: 20 business days for becoming aware that a notifiable activity under Schedule 3 has been or is being carried out, and 24 hours in all other circumstances, including a change in the condition of already-registered contaminated land that is causing or is reasonably likely to cause serious or material environmental harm. The duty falls on owners, occupiers, local government officers and auditors alike.

The Queensland equivalents of the reporting suite are grouped as a “contaminated land investigation document”, defined as “a site investigation report; a validation report; a draft site management plan (or draft amended site management plan)”. Each “must be prepared by a suitably qualified person and then certified by an auditor”, and the department aims to process one within 20 business days. Approval of a site management plan comes with a certificate of approval and a site suitability statement.

Two Queensland features deserve attention on any acquisition.

The first is that a clean register search is not a clean site. The Queensland Government states on its register search page that search results “will not include: contaminated land where we have not been notified of the contamination; land on which a notifiable activity is being, or has been, undertaken but where we have not been notified of the activity”. The register records what has been reported, not what is there.

The second is disclosure on sale. A landowner must give the buyer written notice before agreeing to sell or dispose of registered land, and must also disclose show cause notices, environmental evaluations requiring site investigation, notices requiring a site management plan, clean-up notices and orders under section 458. If the owner does not comply, “the buyer may rescind the agreement by giving the owner written notice” before completion or possession, whichever comes first. Since 1 August 2025, this disclosure has formed part of the Seller Disclosure Statement under the Property Law Act 2023 (Qld), per the Queensland Government’s buying and selling page. Leases carry their own version: 20 business days to notify a lessee of a Contaminated Land Register listing, and 10 business days for the lessee to terminate if that notice is missed.

Getting off the registers requires a contaminated land investigation document, certified by an auditor, demonstrating that no ongoing notifiable activity is being carried out and that the land “is not contaminated land and is suitable for any land use”.

Western Australia: what does a memorial on title do to a development?

Western Australia is the jurisdiction where contamination shows up on the certificate of title, and where it can stop a subdivision. That makes the Contaminated Sites Act 2003 (WA) the one to read before you commit.

Section 11(3) requires an owner, occupier, a person who knows or suspects they caused or contributed to contamination, or an auditor engaged for a report under the Act, to report a site they know is contaminated “within 21 days after the day on which the person first knew that the site was contaminated”, and a site they suspect is contaminated “as soon as it is reasonably practicable to do so”. The stated penalty is $250,000 with a daily penalty of $50,000.

The Department of Water and Environmental Regulation then classifies the site. It states on its page on assessing and classifying contaminated sites that it “can allocate one of seven classifications to sites”. The ones that most affect a development include “possibly contaminated - investigation required”, “contaminated - remediation required”, “contaminated - restricted use”, “remediated for restricted use”, “decontaminated” and “not contaminated - unrestricted use”. Section 23 draws a sharp line that is easy to miss: “The only sites that are required to be remediated under this Act are sites classified as contaminated - remediation required.”

Two provisions then do the commercial damage.

Section 58 requires a memorial to be lodged with the Registrar of Titles for land classified “contaminated - remediation required”, “contaminated - restricted use”, “remediated for restricted use” or “possibly contaminated - investigation required”. That last one is the trap: a memorial attaches before anything is proven, on suspicion alone. Section 58(6) then provides that where such a memorial is registered, the Western Australian Planning Commission “is not to approve under section 135 of the Planning and Development Act 2005 the subdivision of that land, or the amalgamation of that land with any other land”, and a responsible authority is not to grant development approval under a scheme, “without seeking, and taking into account, the advice of the CEO as to the suitability of the land”, the CEO being the chief executive officer of the department administering the Act. Section 58(5) goes further on the worst class, allowing the regulator to specify that instruments affecting the land are not to be registered without its written consent.

Section 68 requires written disclosure “at least 14 days before the completion of a transaction” that would make another person an owner, mortgagee or lessee of land in the three worst classifications, with a copy to the regulator. The stated penalty is $125,000 with a daily penalty of $25,000, and section 68(2) makes a failure to disclose “a breach of statutory duty that … is actionable at the suit of a person who should have been given the disclosure and who has sustained loss or damage in consequence of that breach”.

The searching trap runs the other way from Queensland’s. Section 19 requires the free public contaminated sites database to list only the three worst classifications. Sites classified “possibly contaminated - investigation required” are not on it, even though they carry a memorial. Reaching those records requires a paid summary of records request under section 21, using the department’s Form 2. A free search that comes back empty is not a clean bill of health in Western Australia.

The clean bill of health is a certificate of contamination audit under sections 62 and 63, which the regulator may give “if satisfied, on reasonable grounds, that all contamination on the land that can be identified has been identified”, generally within 45 days of the request or of receiving further information.

South Australia: who carries the liability, and what does a section 7 statement show?

South Australia is the clearest jurisdiction on where liability lands, and it is worth understanding before you negotiate a price on a site with an industrial history.

The South Australian Environment Protection Authority states on its page on site contamination legislation and liable persons that “the original polluter has liability for contamination caused on and off the source site regardless of when it was caused”. Only if that person or company cannot be found does liability pass to the site owner, and even then “the site owner’s liability may be limited to only the owner’s site itself (not off site) and liability is dependent on the owner’s knowledge of the site contamination at the time of purchase”. The owner assumes responsibility where they knew or ought reasonably to have known that chemical substances were present or likely to be present, or that a potentially contaminating activity prescribed by regulations had been or was being carried on.

That knowledge test cuts both ways for a developer. A thorough preliminary site investigation before exchange gives you a price argument. It may also give you the knowledge that engages the test.

Liability can be shifted by agreement under section 103E of the Environment Protection Act 1993 (SA), with agreements entered into after commencement required to be lodged with the regulator. Assessment orders sit in section 103H and remediation orders in section 103J, and both can be registered in relation to the land under section 103O. Section 103P provides for notation of a site contamination audit report in relation to land. The duty to notify sits in section 83A and is narrower than most: the regulator describes it as requiring “a site owner, occupier, auditor or consultant to notify the EPA in writing of the existence of site contamination that affects or threatens underground water, as soon as possible after becoming aware of the site contamination”.

South Australia also splits the professional roles more formally than other states. A “site contamination consultant” assesses the contamination and is expected or recommended to be a certified practitioner assessed by a recognised certification body. An accredited site contamination auditor then reviews that work. Eighteen accredited auditors were listed on the regulator’s audit system page as at 4 August 2026.

On acquisition, the mechanism to know is the section 7 statement. Under the Land and Business (Sale and Conveyancing) Act 1994 (SA) and the Land and Business (Sale and Conveyancing) Regulations 2025 (SA), a vendor must give a prospective purchaser a statement of government interests on Form 1 or Form 2. The regulator’s property interests page records that its statement “answers 33 questions” covering charges and encumbrances, current and historical licences and exemptions, and “various site contamination records”, that statements cost $23.00 per current certificate of title, and and that it works to a statutory timeframe of eight business days to provide one.

Tasmania, the ACT and the Northern Territory

These three are lighter to describe, but each has a feature that could bite.

Tasmania. The definition of a contaminated site is in section 74A(2) of the Environmental Management and Pollution Control Act 1994 (Tas), and section 74B requires owners and occupiers to promptly inform the Director of the Environment Protection Authority when they become aware of contamination. The Tasmanian regulator’s notification page sets the trigger as knowing, reasonably believing, or where the owner or occupier “should in the circumstances reasonably believe that the area of land is or is likely to be a contaminated site”. Part 5A notices, covering investigation, remediation and site management, are the enforcement tools.

The planning trigger is the C14.0 Potentially Contaminated Land Code in the State Planning Provisions, and the Tasmanian regulator notes that the Code “has no practical effect until a Local Provisions Schedule (LPS) is in effect for a Municipal area”. Whether the Code applies to your site is therefore a council-by-council question. Tasmania also differs on lodgement: the regulator states that audits conducted to satisfy planning requirements “should not be submitted to the EPA”, which is the opposite of the South Australian position where audit reports go onto a public index.

Australian Capital Territory. The register of contaminated sites under the Environment Protection Act 1997 (ACT) is deliberately partial. Access Canberra states on its contaminated sites page that the register “does not include all contaminated sites recorded by the EPA. It only records those sites subject to an audit by an Environment Protection Authority (EPA) approved auditor as required under subsection 76(2), 76A(1), 91C(1), 91D(1), 125(2) or 125(3)”. The pathway most developers meet is section 76A(1), where a condition of development approval under the Planning Act 2023 (ACT) requires an auditor to verify assessment and remediation, with the redevelopment of former service station sites for residential use given as the worked example.

Residual obligations attach to the Crown lease rather than a freehold title, through a condition or annotation. A site comes off the register once it has been assessed, remediated if necessary, and independently audited as suitable for the proposed land use with no ongoing management required, and Access Canberra sets out the sixty day windows within which a remediation order or an environment protection agreement must follow an audit assessment if the site is to stay on. Otherwise, “a site entered in the register will remain on it indefinitely”.

Northern Territory. Section 12 of the Waste Management and Pollution Control Act 1998 (NT) requires notification by anyone whose activities have resulted in, spread or enhanced contamination, and by an owner of contaminated land. The Northern Territory Environment Protection Authority’s contaminated land duties page ties the trigger to a numeric exceedance plus a pathway: notification is expected where a contaminant is at or above a level in Schedule B1 of the Assessment of Site Contamination Measure “with respect to a current or approved use of the land, and people have been, or foreseeably will be, exposed”, or where it has entered or will foreseeably enter neighbouring land, the atmosphere, groundwater or surface water above those levels.

The regulator may require an environmental audit under section 48 or issue a pollution abatement notice under section 77. On the planning side, the territory planning department may request an assessment of site contamination or a site audit statement as a condition of a development permit under the Planning Act 1999 (NT) where a more sensitive use or a sensitive use subdivision is proposed. Those pages were last updated in 2022, so departmental names and practice are worth confirming directly.

New Zealand: how does the soil contaminants standard work?

New Zealand runs a single national instrument rather than eight state regimes, which makes it easier to describe and easier to trip over. The Resource Management (National Environmental Standard for Assessing and Managing Contaminants in Soil to Protect Human Health) Regulations 2011 have been in force since 1 January 2012, and the Ministry for the Environment describes them on its standard overview page as “a nationally consistent set of planning controls and soil contaminant values”.

The standard applies to land used, or more likely than not used, for one of 53 activities on the Hazardous Activities and Industries List (HAIL), published by the Ministry for the Environment in 2011. Five activities are then controlled on that land: removing or replacing an underground fuel storage system or its parts, sampling soil, disturbing soil, subdividing land, and changing the use of the land.

Two numeric thresholds decide whether earthworks stay permitted. The Ministry describes small-scale and temporary soil disturbance as “no greater than 25 cubic metres per 500 square metres of affected land” and “no more than two months’ duration” in its guidance for landowners and developers. Exceed either and the permitted pathway closes.

Where the permitted requirements cannot be met, the Ministry states plainly that “your application must include a report of the results of a detailed site investigation, including the results of soil sampling”. Reporting must be done by a suitably qualified and experienced practitioner (SQEP), and the technical standards are the Contaminated Land Management Guidelines, of which No. 1 (reporting) and No. 5 (site investigation and analysis of soils) were both revised in 2021. Anything citing the older editions is out of date.

The exclusions matter as much as the triggers. The standard does not apply to existing uses on listed land, to subdivision of production land that stays production land, to land where a detailed site investigation shows contaminants at or below background concentrations, to a change of use that is not reasonably likely to harm human health, or to areas within a property that were never used for a listed purpose. That last one is worth reading twice: the standard applies only to the actual affected area, not automatically to the whole title.

Regional councils maintain their own registers under different names, such as the Selected Land Use Register (SLUR) in the Wellington region and the Listed Land Use Register (LLUR) in Canterbury. Greater Wellington Regional Council is candid about the limits of its own register, noting that it “is not a final copy of all HAIL sites within the region”, and that “while most registered sites have a verified history of a hazardous activity having taken place, they are not actually contaminated”. Both statements are useful when a lender or a buyer treats a register entry as a finding of contamination.

One structural change is worth watching. The Ministry for the Environment’s resource management reforms page records that the Planning Bill and the Natural Environment Bill were introduced on 9 December 2025, that “Parliament’s Environment Committee completed its scrutiny of the Bills in July 2026”, and that the Government aims to pass them in 2026, with each Bill carrying “its own set of national instruments”. No amendment to the soil contaminants standard has been announced, but the statute it sits under is being replaced, so its long-term form is unsettled.

How long could a site audit take, and what drives the cost?

Timing is the part developers most often underestimate. Environment Protection Authority Victoria puts it directly on its environmental audits page: “An audit of a simple site can take a few months to a year. Big or complex sites often take more than a year to audit.” A preliminary risk screen assessment (PRSA) is faster, and Environment Protection Authority Victoria states on its preliminary risk screen assessment page that one can take several weeks or months to complete, depending on the size and history of the site.

That is the audit alone. It sits on top of the investigation work, the drafting and approval of the remediation action plan (RAP), the works themselves, and validation. On a former service station or a former industrial yard, an eighteen month path from first investigation to a suitability statement would not be unusual, and it is largely serial rather than parallel.

Cost is harder to generalise honestly, and there is no government-published schedule for what a consultant, an auditor or a remediation contractor charges. Rather than quote a range with nothing behind it, it is more useful to know what drives the number, because those are the variables you can test in a fee proposal:

• The remediation strategy. Excavate and dispose off site tends to be the most expensive and the most certain. Containment or capping in place tends to be cheaper up front but leaves you with a long term environmental management plan, ongoing monitoring, and an encumbrance that a future buyer will discount for.
• Waste classification and disposal distance. The classification of the material, the availability of a licensed receiving facility, and the cartage distance can move the number more than the volume does.
• Groundwater. Contamination confined to soil is a construction problem. Contamination in groundwater is a monitoring problem that can run for years and can extend off site, which brings third party liability into view.
• Asbestos and unexpected finds. These tend to drive variations rather than base cost, which is why the unexpected finds protocol in the remediation action plan (RAP) is worth reading closely before you sign the building contract.
• The number of audit iterations. An auditor engaged late who disagrees with the sampling design can send you back to the field.

Where costs are known with reasonable confidence, they belong in the total development cost rather than being buried in a general allowance. Where they are not yet known, the honest place for them is a specific, separately identified provisional sum, kept distinct from the construction contingency so that one does not quietly consume the other.

One number is published. In South Australia, an Environment Protection Authority statement for the section 7 disclosure costs $23.00 per current certificate of title and takes up to 8 clear business days.

How does contamination flow through a feasibility?

It generally comes out of the land price. On a site where the target return is fixed and the end value is set by the market, additional remediation cost and delay have nowhere else to go.

Take a residential infill site in New South Wales, on land that was previously a service station.

The figures below exclude Goods and Services Tax (GST) and are illustrative. They are chosen to show how the arithmetic behaves when remediation lands on a fixed-price acquisition, not as benchmarks for what remediation costs, which as set out above is not a number anyone publishes.

Base case, before any contamination is confirmed:

Second case: the detailed site investigation finds a hydrocarbon plume. Only three inputs change. Remediation, being excavation, disposal and validation, adds $1,100,000. Additional consultant and site auditor fees add $180,000. A six month delay to the programme adds $420,000 in holding and finance costs. Nothing else moves, and the land price stays at the contracted $2,540,000.

Total development cost rises to $21,700,000. Profit falls to $2,300,000. Margin on total development cost falls from 20.0% to 10.6%.

To restore the original 20% margin on total development cost at the same gross realisation, the land would have to be bought for $840,000 instead of $2,540,000. The land price absorbs the full $1,700,000, because at a fixed target margin there is nowhere else for it to sit.

That arithmetic is why the sequencing of due diligence and the sequencing of price agreement matter so much on brownfield land. If the detailed site investigation happens after exchange at a fixed price, the $1,700,000 comes out of profit. If it happens before price is agreed, or under a structure that lets price adjust, it comes out of the land. A put and call option is one of the structures developers use to hold a site while investigation runs, though the duty and tax treatment of options is its own topic and one for your lawyer and accountant.

The delay component is often larger than developers expect. Six months of additional land holding costs and capitalised interest, on a site already carrying acquisition debt, tends to show up in the development cashflow as a step change in peak debt rather than a rounding difference.

What are the traps that catch developers?

A clean register search is not a clean site. Queensland states outright that its register will not show contamination that was never notified. Western Australia’s free database omits the “possibly contaminated - investigation required” class entirely, even though those sites carry a memorial on title. Greater Wellington Regional Council says its register “is not a final copy of all HAIL sites within the region”. Registers record what has been reported.

The trigger is the use, not the works. In Victoria the Environmental Audit Overlay bites on the sensitive use whether or not a planning permit is needed, and a sensitive use counts “even if ancillary to another use”. A caretaker’s flat or a childcare tenancy in a mixed-use podium could bring an audit into a project that was otherwise clear.

Notification duties are personal and time-limited. Western Australia sets 21 days from knowing. Queensland sets 20 business days for a Schedule 3 notifiable activity and 24 hours for harm events. Victoria and Tasmania both use an “ought reasonably to have known” formulation, which means a report sitting unread in a data room may already have started the clock.

Auditors are independent, and that includes being independent of your programme. No regulator will accelerate an audit for you.

Contamination left in place is a permanent obligation. An ongoing maintenance order under section 28 of the Contaminated Land Management Act 1997 (NSW), a long term environmental management plan, a Queensland site management plan, or an ACT Crown lease annotation all follow the land. They restrict what can be done later, and they tend to be priced in by the next buyer.

Disclosure obligations can unwind a sale. A Queensland buyer may rescind where the seller failed to disclose a register listing. A Western Australian buyer, mortgagee or lessee who should have received a section 68 disclosure has a statutory right of action for loss. These are seller-side risks on your exit as much as buyer-side risks on your entry.

Investigation is iterative. The Assessment of Site Contamination Measure notes that many investigations proceed in multiple stages because of complexity or unexpected finds. A due diligence period built around one round of sampling may be too short.

What is changing in 2026?

Auditor accreditation is going national. A National Harmonised Auditor Accreditation Process (NHAAP) is being introduced to give a single national route to initial accreditation. The South Australian Environment Protection Authority states that the inaugural round commences in September 2026, “with applications open from Tuesday 1 September to Thursday 15 October 2026”. The Queensland Government confirms the same dates and now requires “evidence of a favourable report from the National Harmonised Auditor Accreditation Process (NHAAP)” for new applications. The Western Australian regulator records that the inaugural round “commenced in August 2026”.

Victoria is sitting out the first round. Environment Protection Authority Victoria states that it is “not participating in the first accreditation round, as Victoria recently completed an initial contaminated land auditor appointment process in 2024-25”, and intends to participate in the second.

For a developer this is mostly a supply question rather than a compliance one. Accreditation moving to a common process may widen the pool over time. In the short term, the same small number of accredited people are doing the work, and the auditor’s availability may be the binding constraint on your programme rather than the consultant’s.

What to ask your environmental lawyer, environmental consultant and site auditor

The questions below are the ones that decide the topic on your own facts. They are deliberately not answered here, because the answers turn on the site, the jurisdiction, the proposed use and the contract.

For your environmental lawyer

• On this title, in this state, has any notification duty already been triggered by what is in the data room, and if so, when did the clock start and who does it fall on?
• If we exchange before the detailed site investigation is complete, do we acquire a notification duty, a duty to manage, or both, and from what moment?
• What exactly does the vendor have to disclose to us here, what have they disclosed, and what remedy would we have if it turns out to be incomplete?
• If we sell before the audit is finalised, what must we disclose to our buyer, and could a failure give them a right to rescind or a statutory claim?
• Can liability for pre-existing contamination be transferred or apportioned by agreement in this state, and if so, what has to be lodged with the regulator for that to hold?
• Is there a memorial, notation, order or lease annotation on or foreshadowed against this land, and what does it prevent us doing without the regulator’s consent?
• If contamination is left in place under a management plan, what obligations bind us afterwards, and what do they do to a future sale or to a subdivision?
• Can we structure the acquisition so price adjusts if the detailed site investigation finds more than the preliminary site investigation suggested, and what does that structure cost in duty terms?

For your environmental consultant

• Based on the site history, what is your assessment of the likelihood that a detailed site investigation is required, and what would move that assessment either way?
• What contaminants of potential concern do you expect here, and which of them could reach groundwater?
• What sampling density and which investigation levels do you propose, and has the auditor agreed the sampling design before we start?
• What is the realistic range of remediation strategies for this contamination and this proposed use, and what does each do to programme, disposal cost and residual obligations?
• What would trigger a further stage of investigation, and how many stages should we budget for?
• What is your view on the split between what should sit as a firm cost and what should sit as a provisional sum in our cost plan?
• Which permits or approvals does the remediation itself need, and how long do those take in this council area?

For your site auditor

• What is your current availability, and what turnaround should we programme for review at each stage?
• What would you need to see before you could form a view on suitability for the proposed use, and what would cause you to send work back?
• Is a preliminary risk screen assessment (PRSA) or the equivalent front-end step available and sensible here, or should we go straight to audit?
• Would you accept the sampling design and the criteria in the draft remediation action plan (RAP), or would you want them changed before the works start?
• If contamination is left in place, what would the ongoing management requirements look like, and what would go into a long term environmental management plan?
• Who receives your statement, on what timeframe, and does it go onto a public register or a planning certificate?