---
title: "PSI vs DSI vs Compliance Check: What Does Your Site Actually Need?"
description: PSI vs DSI vs a compliance check — what each does, what a PSI costs in Victoria, and which one your site actually needs. Plain-English guide.
---

[Industry Articles](https://automatedenvironmental.com.au/industry-articles)

# [PSI vs DSI vs Compliance Check: What Does Your Site Actually Need?](https://automatedenvironmental.com.au/industry-articles/psi-vs-dsi-vs-compliance-check)

 Written by [Chris Ford](https://automatedenvironmental.com.au/industry-articles/author/chris-ford) | Aug 8, 2026, 6:35:09 AM

*By Automated Environmental · For Victorian property owners, buyers and managers. Last reviewed August 2026.*

## PSI vs DSI vs a compliance check — which one does your site need?

The three are different instruments for different questions, and confusing them is expensive. A **Preliminary Site Investigation (PSI)** is a desktop-based screening that tells you whether contamination is *plausible*. A **Detailed Site Investigation (DSI)** is intrusive sampling that tells you whether contamination is *actually present* and at what levels. A **routine compliance check** is a recurring visual and documentary screening that tells you whether a site is *meeting its stated obligations* — it is not a contamination assessment at all.

Choosing the right one first is the difference between a proportionate spend and paying for a detailed investigation your site never needed.

## Preliminary Site Investigation (PSI)

A PSI is the usual starting point. It is a **desktop review plus a site inspection**: the site's history, past land uses, surrounding land, available records and a walk-over, assembled into a view of whether contamination is plausible and where it would most likely be. A PSI does not involve sampling or laboratory analysis.

You would typically commission a PSI for due diligence ahead of a purchase or lease, in response to a planning trigger, or to establish a baseline. It answers the question: *"Is there a reason to look further?"*

## Detailed Site Investigation (DSI)

A DSI is the follow-on when a PSI (or another trigger) says there is a plausible issue worth confirming. It is **intrusive**: soil, and often groundwater, is sampled and analysed, so a DSI produces hard data on what is present, at what concentration, and whether it poses a risk to human health or the environment.

A DSI is a materially larger commitment than a PSI. It is the right instrument when you genuinely need to characterise contamination — for a transaction, a clean-up decision or a regulatory requirement — and the wrong one when all you needed was a screening.

## Routine compliance check

A routine compliance check is a different category altogether. It is a **recurring, fixed-fee screening of a site against its stated obligations** — the clauses in a lease, the conditions of a licence, the duties under the Environment Protection Act 2017. It is photo-evidenced and produces a short, dated summary, with every finding traceable to its source obligation.

Two things are important to be precise about. A compliance check is **not** an intrusive contamination assessment, and it offers **no opinion on contamination status**. It does not substitute for a PSI or a DSI. What it does is give an owner or manager a **standing, documented view** across a site or portfolio — and a clear, early signal when something genuinely warrants a PSI.

## Which one does your site actually need?

The proportionate sequence, most of the time, is this:

- **Nothing suggests contamination and you just need assurance?** A routine compliance check gives you a dated, defensible record without intrusive cost.
- **Buying, leasing, refinancing, or a planning trigger?** Start with a PSI. It tells you whether there is anything to look into further.
- **A PSI or a finding flags a plausible issue?** Then a DSI is the proportionate step — now with a clear scope, not a fishing expedition.

For a portfolio, the logic scales: routine checks across every site identify the small number that genuinely need a PSI, and only findings escalate to a DSI. You stop paying for assessments you didn't need and start catching the ones you do.

## What does a PSI cost in Victoria?

Costs vary with site size, history and complexity, so any figure is indicative only. As a broad guide, a desktop-based PSI is commonly priced in the low thousands of dollars, while a DSI with sampling and laboratory analysis runs considerably higher. The point of sequencing correctly is to avoid paying DSI money where a PSI — or a simple compliance check — would have answered the real question.

## Frequently asked questions

### Is a compliance check a substitute for a PSI?

No. A compliance check is a visual and documentary screening against stated obligations. It offers no opinion on contamination status and does not replace a PSI. Where a check observes something that needs assessment, it triggers a scoped PSI proposal.

### Do I always need a DSI after a PSI?

No. Many PSIs conclude there is no plausible contamination issue, and that is the end of it. A DSI is only warranted where the PSI or another trigger identifies something that genuinely needs confirming with sampling.

### When is a PSI required in Victoria?

Common triggers are a planning application for a sensitive use, a transaction (purchase, lease or refinance), a lender or legal requirement, or an EPA interaction. It is also a sensible baseline for any industrial or legacy site.

### What is the cheapest way to keep an eye on a portfolio?

A recurring compliance check per site is the proportionate option. It keeps a dated, source-traceable record across the portfolio and escalates to a PSI only where a finding warrants it — far cheaper than periodic intrusive assessments of every site.

Related reading: [Section 39 explained](https://automatedenvironmental.com.au/industry-articles/who-is-responsible-for-contaminated-land-victoria-s39), [landlord liability for tenant contamination](https://automatedenvironmental.com.au/industry-articles/landlord-liability-tenant-contamination-victoria), and our [Preliminary Site Investigations](https://automatedenvironmental.com.au/preliminary-site-investigations/) service.

*This article is general information only, not legal advice. Costs are indicative and vary by site; confirm the right instrument for your situation with a qualified practitioner before acting.*

[View full post](https://automatedenvironmental.com.au/industry-articles/psi-vs-dsi-vs-compliance-check)

```json
{
  "@context" : "http://schema.org",
  "@type" : "BlogPosting",
  "author" : {
    "@type" : "Person",
    "name" : "Chris Ford"
  },
  "dateModified" : "2026-08-08T06:35:12.053Z",
  "datePublished" : "2026-08-08T06:35:09Z",
  "headline" : "PSI vs DSI vs Compliance Check: What Does Your Site Actually Need?",
  "image" : {
    "@type" : "ImageObject",
    "height" : 60,
    "url" : "/hs/hsstatic/content_shared_assets/static-1.4092/img/default-amp-logo.png",
    "width" : 60
  },
  "mainEntityOfPage" : "https://automatedenvironmental.com.au/industry-articles/psi-vs-dsi-vs-compliance-check",
  "publisher" : {
    "@type" : "Organization",
    "logo" : {
      "@type" : "ImageObject",
      "height" : 60.0,
      "url" : "https://47551411.fs1.hubspotusercontent-na1.net/hubfs/47551411/Logo/Automated%20Environmental%20Melbourne.png",
      "width" : 95.6448
    },
    "name" : "Industry Articles"
  }
}
```