Contaminated land in Western Sydney DAs: former farms, market gardens and fill

When a NSW council assesses a DA, Chapter 4 of State Environmental Planning Policy (Resilience and Hazards) 2021 requires it to consider whether the land is contaminated and, if it is, whether it is or can be made suitable for the proposed use. That is why councils in Western Sydney regularly ask for a preliminary site investigation on duplex, townhouse and subdivision sites that were once market gardens, orchards, poultry farms or rural properties, or that contain imported fill. The guidance behind this, the Managing Land Contamination Planning Guidelines, lists agricultural and horticultural activities among the land uses that can leave contamination from fertilisers, pesticides and herbicides. For developers, the cheapest point to answer the question is before purchase, not after the council’s first request for information.

Who this is for: developers and investors buying former rural or semi-rural land in Blacktown, the Hills, Camden, Liverpool, Penrith and the Hawkesbury for dual occupancies, townhouses or small subdivisions, who want to understand when contamination reporting will be required and how it affects cost and program.

Why does the council care about contamination on a house or duplex site?

Because the council is the planning authority that permits a more sensitive use. Residential development, particularly with gardens where children play, is among the most sensitive uses. The NSW Department of Planning’s contaminated lands page explains that the former State Environmental Planning Policy No 55 now sits in Chapter 4 of the Resilience and Hazards SEPP, and that it provides a statewide framework for the remediation of contaminated land and to minimise the risk of harm. The Department’s fact sheet confirms the consolidation took effect on 1 March 2022 with the provisions largely unchanged.

Under the SEPP, the consent authority must not grant consent unless it has considered whether the land is contaminated and, if so, is satisfied the land is suitable in its contaminated state, or will be after remediation, for the proposed purpose. Where the proposal involves a change of use on land that may have been used for a contaminating activity, the council will usually want a preliminary investigation before it can be satisfied.

Which past uses trigger a contamination report?

The Managing Land Contamination Planning Guidelines include a list of industries and activities that may cause contamination, with the chemicals associated with each. Agricultural and horticultural activities are on that list, linked to fertilisers, insecticides, fungicides and herbicides. On residential sites, the triggers we see most often are:

Aerial photographs (historical imagery back to the 1940s and 1950s is often available), the section 10.7 planning certificate, council records and a site walkover usually tell the story. A planning certificate notation about contamination is a strong signal, but the absence of one does not mean the land is clean.

What is the difference between a preliminary and detailed investigation?

The Planning Guidelines describe a staged process. A preliminary investigation aims to identify past or present potentially contaminating activities, provide a preliminary assessment of any contamination and, if required, a basis for a more detailed investigation. The Guidelines are explicit that a preliminary investigation is not necessary where contamination is not an issue. A detailed investigation is only necessary when the preliminary investigation indicates that the land is contaminated or may be.

In practice, for a duplex on a former farm lot, a preliminary site investigation (often called a PSI) by a qualified environmental consultant reviews history, inspects the site and may include limited soil sampling. If results are clean, the PSI concludes the site is suitable. If not, a detailed site investigation, a remediation action plan and validation follow. On larger or more complex sites, some councils ask for a site audit statement from a NSW EPA accredited site auditor.

Category 1 or Category 2 remediation: what is the difference?

Remediation work under Chapter 4 falls into two categories. Category 1 remediation needs development consent, often as part of the main DA. Category 2 remediation can be carried out without consent, but the Guidelines’ process requires the council to be notified of the proposed remediation, the work carried out in line with the submitted information, validation obtained from a qualified expert at completion, and the council notified of the validation within a month. For most small residential sites with localised contamination (a hotspot of asbestos fragments, for example), Category 2 is common. Where remediation is extensive or the site sits in a sensitive area, Category 1 is more likely. The SEPP sets out which applies.

The due diligence sequence we recommend

1. Before exchange, review historical aerial imagery for orchards, sheds, dams, fill and buildings that have since gone.
2. Read the section 10.7 certificate for contamination notations and check council records.
3. If the history is rural or unclear, commission a preliminary site investigation before buying, or make the contract conditional on one.
4. If the PSI recommends sampling or a detailed investigation, price it and the likely remediation into the purchase.
5. Lodge the DA with the PSI (and any detailed investigation or remediation plan) so the council can be satisfied under Chapter 4 at the start.
6. Carry out remediation in the right category, keep the validation report and give it to the council.
7. Keep all reports with the title documents. Buyers of the finished dwellings will ask.

Where projects lose time and money

The expensive pattern is buying a former rural lot at a residential price, designing four townhouses and then receiving an RFI asking for a PSI. If sampling finds pesticide residues or asbestos, the program slips by months and remediation costs come straight out of the margin. The second pattern is demolition without a plan. Knocking down an old fibro cottage carelessly can contaminate a clean site with asbestos fragments, turning a clean preliminary report into a remediation job. The third is fill. Lots with a former dam or a low corner that has been filled are worth testing, because uncontrolled fill is where unknowns hide.

Contamination also matters earlier, at rezoning. Ministerial Direction 4.4 under section 9.1 of the EP&A Act requires contamination to be considered when land is rezoned, which is why growth area precincts usually carry precinct-wide contamination studies. Those studies are general; they do not clear your individual lot.

Definitions

Preliminary site investigation (PSI)

A first-stage investigation that identifies past and present potentially contaminating activities and gives a preliminary assessment of contamination.

Detailed site investigation

A sampling-based investigation that defines the type, extent and level of contamination, needed when a PSI shows contamination is likely.

Remediation action plan (RAP)

A document setting out how contamination will be removed, treated or managed so the land is suitable for its intended use.

Validation

Confirmation by a qualified expert, after remediation, that the land meets the clean-up objectives.

Site audit statement

An independent review and statement by a NSW EPA accredited site auditor about the suitability of land for a specified use.

Contamination history is one of the first things we check in a development due diligence report on former rural land in the Western Sydney growth areas, and we coordinate the consultant’s findings into the planning case for the DA. If you are looking at a former farm or market garden lot, request a fee proposal before you exchange.