If you own property or are developing in Perth or regional Western Australia, there could be a serious environmental risk sitting just metres beneath your feet.
Old underground fuel tanks (sometimes installed decades ago and long forgotten) can leak petroleum into surrounding soil and groundwater without any visible warning. Left undetected, these tanks become costly liabilities that affect property values, delay development and trigger regulatory action.
West Soil & Water helps Perth property owners identify, assess and manage these hidden contamination risks before they escalate.
Click here to request a soil and groundwater contamination assessment around a septic or fuel tank.
What Are Underground Fuel Tanks and Where Are They Found
Underground fuel tanks (also called underground petroleum storage tanks or USTs) are buried vessels used to store petrol, diesel, heating oil and other hydrocarbons. They were widely installed across Western Australia from the mid-twentieth century, particularly at service stations, bulk fuel depots, industrial estates and rural properties without access to reticulated fuel services.
Many of these tanks were single-walled steel construction with minimal corrosion protection. Today, most pre-1990s installations are increasingly prone to deterioration.
In many cases, tanks have been decommissioned but remain in the ground, sometimes without any record of their existence. This poses a serious contamination risk for property owners, developers and inhabitants alike.
The Contamination Risks You Can’t See
Underground fuel tanks deteriorate as their steel walls corrode, joints and seals fail, and general wear and tear takes hold. Changes in surrounding soil and settlement also play a part.
In older tanks without cathodic protection or secondary containment, this creates leaks that can go undetected for many years, causing:
Soil Contamination
When tanks leak, hydrocarbons migrate into the surrounding soil. Perth’s notoriously sandy soils allow for the rapid vertical migration of these contaminants and where clay layers are present, movement may be slowed or diverted, but contamination still accumulates.
Groundwater Contamination
Once hydrocarbons reach the water table, they spread laterally, forming plumes that affect groundwater quality across a wide area. Certain compounds (like benzene) are highly soluble and toxic even at low concentrations.
Many Perth properties are located within or near Public Drinking Water Source Areas (PDWSAs) or Underground Water Pollution Control Areas, where groundwater sources supply drinking water and irrigation. Here, contaminated groundwater poses serious public health risks, including exposure through bore water and vapour intrusion into buildings.
Health and Environmental Impacts
BTEX compounds (benzene in particular) are recognised carcinogens. Their spread through fuel contamination can affect water quality in nearby bores and waterways, damage vegetation, harm aquatic ecosystems and create long-term exposure risks for residents.
This creates a long lasting risk. Many hydrocarbons can persist in soil for decades and other compounds can migrate as vapour into occupied buildings.
Financial and Legal Consequences
The financial and regulatory consequences of underground fuel or septic tank contamination are significant.
- Remediation costs can range from tens of thousands to millions of dollars depending on the scale of contamination. Large spills may require extensive soil excavation, installation of recovery wells and ongoing groundwater treatment.
- Unexpected property development delays are common when site investigations reveal contamination that must be remediated before approvals are granted.
- Regulatory obligations require property owners to assess, report and remediate contaminated land. Non-compliance can result in fines and enforcement action.
- Property values decline when contamination is identified or suspected. Lenders and purchasers increasingly require environmental site assessments and insurance coverage may be refused for non-compliant sites.
- Legal liability falls on the property owner, even if the contamination predates their ownership.
4 Warning Signs Your Property May Have Underground Tanks
If you suspect your property may have a buried fuel tank, a failing septic system or any form of subsurface contamination, take action early:
- Don’t ignore the signs. Odours, soil staining, stressed vegetation and water quality changes all warrant investigation. Delays only increase the extent of contamination and the cost of remediation.
- Commission a professional assessment. A qualified environmental consultant (like West Soil & Water) can conduct desktop research, inspect the site and collect soil and groundwater samples to determine whether contamination is present and how far it has spread.
- Understand your obligations. Under WA law, property owners have a duty to report and manage contaminated sites. Early detection puts you in a stronger position to manage costs and comply with regulatory requirements.
- Plan remediation if needed. Where contamination is confirmed, West Soil & Water develops site management plans and remediation strategies tailored to the specific conditions.
Early investigation is consistently the most cost-effective approach. Issues identified before a transaction or development application avoid the delays, disputes and inflated costs that come with late discovery.
Get in Touch and Protect Your Investment
Underground fuel tanks and failing septic systems share one critical characteristic: they can contaminate soil and groundwater for years without any visible warning.
For property owners across Perth and Western Australia, proactive environmental assessment is the most effective way to protect your investment, avoid regulatory liability and safeguard the health of your tenants and community.
West Soil & Water has the expertise, local knowledge and laboratory partnerships to identify hidden contamination risks and guide you through assessment, compliance, and remediation.
Contact West Soil & Water today to arrange a site assessment.
Frequently Asked Questions
How much does an underground tank assessment cost and what does it include?
Costs depend on the size and complexity of the site, the number of samples required and whether groundwater monitoring is needed. An assessment typically includes a desktop review, site inspection, soil sampling, NATA-accredited laboratory analysis and a detailed report with risk assessment and remediation recommendations.
Contact our office for a site-specific quote.
How long does the investigation process take?
Most site assessments are finalised in less than three weeks, including laboratory turnaround. Complex sites with extensive groundwater monitoring may require additional time.
What happens if contamination is found on my property?
If contaminants exceed WA guideline levels, a remediation plan is developed. Options may include soil excavation, in situ treatment, containment or monitored natural attenuation. West Soil & Water provides reporting that satisfies regulatory requirements and supports development or transaction approvals.
Do I need permits for environmental site investigations?
Standard soil and groundwater investigations generally do not require specific permits, though work within water protection areas or involving bore installation may require approvals. West Soil & Water advises on any regulatory requirements applicable to your site.
Can West Soil & Water help with remediation planning and compliance?
Yes. We provide remediation planning, site management plans, validation sampling and ongoing monitoring to ensure contaminated sites meet WA regulatory standards and achieve closure.