Check Your Groundwater (CYG) areas

Understand how Check Your Groundwater areas can help you locate and manage contaminated groundwater.

On this page

A Check Your Groundwater (CYG) area is an area or precinct where we know groundwater has been contaminated by:

  • an activity
  • waste
  • pollution
  • contaminated land.

We identify CYG areas by assessing if contaminants are above the standards in the Environment Reference Standard. CYG areas are where contaminant levels threaten one or more environmental values.

The groundwater in a CYG area may not be suitable for some uses. It may be harmful to human health and the environment.

Knowing that an area is a CYG area is helpful if you:

  • want to use groundwater in the area
  • live in or near the area
  • manage or control a site in the area.

It can also help environmental consultants and government authorities to understand the environmental condition of groundwater.

It's important for anyone who wants to use groundwater in these areas to test it to make sure it's safe to use.

If you want to develop groundwater at your site, you can check for a CYG area. Knowing if your site is within – or close to – a CYG area lets you know if there are potential water quality issues or restrictions on how you can use the groundwater.

You should test the groundwater before you use it, so you know what it can be safely used for.

To learn more about your obligations, visit Manage a Check Your Groundwater area.

Groundwater Quality Restricted Use Zones

Under the old Environment Protection Act 1970, areas of contaminated groundwater were identified as Groundwater Quality Restricted Use Zones (GQRUZs).

GQRUZs are sites that are considered to have been cleaned up as far as reasonably practicable, as determined by an environmental auditor. Restrictions still apply to how the water in these areas can be used without further treatment.

Areas that were GQRUZs are now described as CYGs at post remediation status.

Unlike GQRUZs, CYG areas can be identified without an environmental audit.

How we identify a CYG area

As well as assessing if contaminant levels are above the standards in the Environment Reference Standard, we may also use information from environmental audits – for example, a suitability of land use audit. We may do this where:

  • groundwater has been cleaned up but contamination remains
  • groundwater has been assessed as part of the environmental audit
  • a historical environmental audit recommended a GQRUZ.

If you're in management or control of land, we contact you when we're assessing a potential CYG area on your site.

CYG area status

The CYG area status helps you understand how much investigation and clean-up of the groundwater has been done.

We assign a CYG area one of 3 statuses:

  1. Post remediation – clean-up of groundwater has been done, but some groundwater contamination remains. All former GQRUZs have this status.
  2. Under assessment – further monitoring, evaluation and/or remediation of the groundwater is expected.
  3. Precinct – the source of groundwater contamination is not clear. There's evidence it comes from multiple sites. Clean-up of the groundwater cannot be effectively completed.

Each status has the same requirements and responsibilities for managing the groundwater.

Users of groundwater within a CYG area need to make sure the groundwater is suitable before using it. For more information, visit Use groundwater safely.

How we change or remove CYG areas

When assessments and investigations show a CYG area has changed, we can:

  • change the extent of a CYG area boundary
  • remove a CYG area.

We need to have evidence to do this. This can be assessment reports showing that:

  • the size of the geographical and vertical extent of the contaminated groundwater (plume extent) has changed
  • groundwater quality is no longer impacted because all the relevant standards for groundwater have been achieved or maintained.

Information sources we may use when we decide whether to change or remove a CYG area include:

  • assessment reports in response to remedial notices
  • follow-up to contaminated land notifications
  • environmental audits
  • an outcome from a groundwater monitoring review, in response to a trigger or condition being met in a groundwater monitoring plan.

Find a CYG area

You can find CYG areas and GQRUZs on Victoria Unearthed.

The map provides information on:

  • CYG area status
  • what uses the groundwater may not be suitable for, such as drinking or watering gardens
  • the risks of using or coming into contact with the groundwater
  • how far the contaminated groundwater area extends
  • the accompanying assessment report, where available
  • a link to view and print a one-page report showing the location and information.

You can also see GQRUZs and other information about groundwater at Visualising Victoria’s Groundwater.

Groundwater areas not shown

When information about a particular area is not shown on Victoria Unearthed, it does not mean that the groundwater there is suitable for use. The groundwater may not have been tested.

If a CYG area is not shown on Victoria Unearthed, other ways to get water quality information include:

You should test for a broad range of contaminants before using groundwater. For more information, visit Use groundwater safely.

Download CYG area datasets

You can download the CYG area point and polygon datasets from:

If you have problems accessing the data, contact us on contact@epa.vic.gov.au or 1300 372 842.

Disclaimer

Any information contained in a CYG area dataset is intended to be used as a guide only. We do not verify they are accurate or complete.

We do not accept any responsibility for any claims, loss or damage of any kind arising out of any person’s reliance on any information that either:

  • is contained in or omitted from the CYG area dataset
  • arises out of the inclusion or exclusion of any land, location, site or property in a CYG area.

Note there are limitations to the frequency of updates and currency of information of these sites.

Updated

Back to top