How Much Does a Preliminary Site Investigation Cost in NSW?

For a relatively straightforward site, a Preliminary Site Investigation (PSI) in NSW may typically cost somewhere in the order of $3,500 to $5,500, particularly where the assessment does not require soil sampling and the site has a reasonably simple history.

That should only be treated as an indicative range.

The cost of a PSI can vary considerably depending on the property, the purpose of the assessment and the amount of work required to reach a defensible conclusion.

At the other end of the spectrum, a large or complex commercial or industrial site with multiple Areas of Environmental Concern, intrusive investigation, extensive historical records, independent Site Auditor involvement and multiple rounds of technical review may cost $10,000 or considerably more.

The important point is that there is no single standard PSI price.

A PSI should be scoped to the property and the question being asked.

If you require a project-specific price, see our Preliminary Site Investigation services in NSW or send us the site address and proposed development for a quote.

What Affects the Cost of a PSI?

1. Whether Soil Sampling Is Included

Not every PSI requires soil sampling.

Where a site has a relatively straightforward history and no significant unresolved contamination issues, the assessment may primarily involve:

• historical and environmental research;

• Council and property records;

• a site inspection;

• development of a Conceptual Site Model; and

• preparation of the PSI report.

This is generally less expensive than a PSI involving intrusive investigation because there is less field time, no or limited laboratory analysis and less data to interpret in the report.

However, targeted sampling can sometimes be a cost-effective addition to the PSI.

For example, a property may contain a small area of imported fill beneath a driveway. If the origin of that material cannot be established, one or two appropriately targeted samples may provide useful evidence that the fill represents a relatively low contamination risk.

Without that information, the uncertainty may remain unresolved and require further investigation later.

The question should therefore not be:

“Does every PSI need sampling?”

It should be:

“Will targeted sampling meaningfully resolve an identified uncertainty?”

For more information, see Does a Preliminary Site Investigation Need Soil Sampling?

2. How Much Sampling Is Actually Required?

Where soil sampling is included, the cost depends heavily on the investigation scope.

A PSI with two targeted samples from a small area of fill is very different from a site containing several potential Areas of Environmental Concern requiring multiple investigation locations.

The number of samples may be influenced by:

• the size of the site;

• the number and distribution of Areas of Environmental Concern;

• the type of contamination being investigated;

• the depth of investigation required;

• accessibility;

• the sampling method;

• laboratory analytical requirements; and

• the level of confidence required from the investigation.

Field effort can therefore become one of the largest variables in the overall price.

For example, collecting shallow samples from accessible locations using a hand auger may be relatively straightforward.

Advancing several hand-auger locations to around two metres below ground level can require substantially more field time, particularly in difficult ground conditions.

Conversely, if geotechnical drilling is already being undertaken at the property, it may sometimes be possible to coordinate the environmental investigation with the same drilling programme.

Where appropriate, using the existing drill rig and mobilisation can reduce duplicated field costs and allow both investigations to be completed more efficiently.

A well-designed investigation therefore considers how the required information can be collected most efficiently, not simply how many samples can be taken.

3. The Size and Number of Lots

The size of the property affects both the desktop assessment and the time required on site.

A single-lot property may require one section 10.7 planning certificate and one chain of historical title information.

If a development site comprises multiple lots, additional planning certificates, title searches and ownership histories may be required.

There is a direct cost associated with obtaining those records, but there is also additional consultant time involved in reviewing and interpreting them.

A larger property will generally also take longer to inspect, particularly where there are multiple buildings, operational areas, stockpiles or potential contamination sources.

4. The Complexity of the Site History

Site history is often one of the biggest influences on the cost of a PSI.

A relatively simple site might involve:

• residential or low-intensity commercial use;

• a small amount of uncontrolled fill; and

• perhaps a potential asbestos-in-soil issue.

The resulting Conceptual Site Model (CSM) may be relatively straightforward.

A large commercial or industrial property may instead have:

• multiple historical owners;

• changing industrial activities;

• workshops;

• fuel infrastructure;

• chemical storage;

• waste disposal;

• historical filling; and

• several neighbouring potentially contaminating land uses.

Each potential source needs to be considered in the context of:

Source → Pathway → Receptor

The consultant then needs to determine which issues genuinely matter and which historical activities do not represent a credible risk to the proposed development.

The more complicated that history becomes, the more time is required to develop and document a defensible CSM.

For more information, see What Is a Conceptual Site Model in Contaminated Land Assessment?

5. The Purpose of the PSI

The reason the PSI is being prepared can also materially affect the scope and cost.

A relatively straightforward PSI supporting a Development Application may have different reporting requirements to an investigation forming part of a major project under independent EPA-accredited Site Auditor review.

Auditor-reviewed projects can require substantially more detailed documentation of:

• historical evidence;

• Areas of Environmental Concern;

• data gaps and uncertainty;

• the Conceptual Site Model;

• investigation rationale;

• limitations; and

• the basis for the consultant's conclusions.

They may also involve additional technical review and responses to auditor comments.

For a complex site containing multiple Areas of Environmental Concern, the PSI may involve substantial fieldwork, reporting and review.

In those circumstances, a PSI costing more than $10,000 would not be unusual.

The scope needs to reflect what the report is actually expected to achieve.

6. How Quickly the Report Is Required

Timeframe can also affect the price.

Where the project can be scheduled within a normal programme, the investigation can generally be completed using standard resourcing and review processes.

A significantly compressed timeframe may require:

• reprioritising other work;

• additional staff resources;

• overtime;

• expedited searches;

• expedited laboratory turnaround; and

• accelerated technical review.

An urgent PSI can therefore cost more than the same investigation delivered under a standard timeframe.

If programme is important, it is useful to raise this when requesting a proposal rather than after the investigation has commenced.

For more information, see How Long Does a Preliminary Site Investigation Take?

7. Time Required on Site

The amount of field time required can have a significant influence on the cost of a PSI.

A small and uncomplicated property may only require a relatively short site walkover.

A larger industrial, commercial or rural site may require considerably more time to inspect and understand, particularly where there are multiple buildings, operational areas or potential contamination sources.

Where sampling is required, field time can increase further depending on:

• the number of investigation locations;

• sampling depth;

• ground conditions;

• access;

• drilling or excavation requirements;

• decontamination requirements; and

• the amount of material that needs to be logged and sampled.

This is why two sites of a similar area can have very different investigation costs.

The site that can be efficiently inspected and sampled using existing access or a concurrent geotechnical investigation may require substantially less field effort than a site requiring multiple standalone mobilisations or difficult manual sampling.

So, What Should You Budget for a PSI?

As a broad indication, a relatively straightforward PSI without soil sampling may fall somewhere around $3,500 to $5,500.

Where targeted soil sampling, additional historical searches or more extensive fieldwork are required, the cost will generally increase above that range.

For large or complex commercial and industrial sites, particularly where there are multiple Areas of Environmental Concern, substantial intrusive investigation or independent Site Auditor involvement, the PSI may cost more than $10,000.

These figures are general indications only.

A small site can still be complex, while a relatively large property with a simple and well-documented history may require less work than expected.

The actual price comes down to how much work is reasonably required to answer the contamination question for that particular property.

Does a Cheaper PSI Mean a Worse PSI?

Not necessarily.

A simple site should not require an unnecessarily complicated investigation.

Likewise, reducing the scope of a complex investigation purely to achieve the lowest fee can create problems if important uncertainties remain unresolved.

When comparing PSI proposals, it is worth looking beyond the total price and asking:

• What historical searches are included?

• Are Council records being reviewed?

• Is a site inspection included?

• Is a Conceptual Site Model being developed?

• Is soil sampling included, and if so, why?

• How much fieldwork is proposed?

• Is specialist technical review required?

• What question is the PSI intended to answer?

Two consultants may therefore quote different amounts because they are proposing different scopes, not necessarily because one simply charges more than the other.

How Confluence Approaches PSI Pricing

Our approach is to keep the investigation proportionate to the property and the purpose of the assessment.

We do not automatically include soil sampling simply because a PSI is being undertaken.

Equally, where a small amount of targeted investigation can efficiently resolve an important uncertainty, it may be more economical to address it during the PSI rather than require a separate mobilisation and report later.

Where environmental sampling can sensibly be coordinated with other site work, such as a geotechnical investigation, we also consider whether the field programme can be combined to reduce duplication and improve efficiency.

The objective is not to undertake the smallest investigation possible or the largest.

It is to undertake the right investigation for the question being asked.

Get a Project-Specific PSI Quote

The quickest way for us to provide an appropriate scope and fee is to send us:

• the property address;

• proposed development or reason for the assessment;

• Council correspondence, if available;

• relevant plans; and

• previous environmental reports.

We can review the available information and determine what is actually required for the property.

Learn more about our Preliminary Site Investigation services in NSW or contact Confluence Environmental for a project-specific quote.