Underground Petroleum Storage System (UPSS)
Summary
An Underground Petroleum Storage System (UPSS) is an underground system used to store petroleum products such as petrol, diesel or waste oil. UPSS typically consist of underground tanks, associated pipework, pumps and fittings.
UPSS are a common source of soil and groundwater contamination, particularly at former service stations, depots and industrial sites. Identification and assessment of UPSS is a key consideration in contaminated land investigations and development planning.
Definition
An Underground Petroleum Storage System is an integrated system designed to store petroleum products below ground. The system may include storage tanks, fill points, pipework, dispensers and leak detection components.
Over time, corrosion, mechanical failure or poor maintenance can result in leaks, leading to contamination of surrounding soil and groundwater.
Why Underground Petroleum Storage Systems Matter
From an environmental perspective, leaking UPSS are a well-recognised source of hydrocarbon contamination, including petroleum hydrocarbons, BTEX compounds and, in some cases, additives.
From a planning and regulatory perspective, the presence or former presence of a UPSS can trigger requirements for contaminated land assessment, remediation or validation before development or land-use change can occur.
UPSS-related contamination can also affect construction methodology, dewatering requirements and waste classification. Early identification of UPSS reduces the risk of unexpected contamination during excavation and helps avoid project delays.
Where UPSS Are Commonly Encountered
Underground petroleum storage systems are commonly associated with:
Service stations and fuel depots
Industrial and commercial sites with fuel storage
Transport depots and maintenance facilities
Former automotive or mechanical workshops
Sites with historical fuel handling or storage
UPSS may still be present below ground even where surface infrastructure has been removed.
When UPSS Assessment Is Typically Required
Assessment of UPSS is commonly required where:
Development is proposed on land with historical fuel storage
A Preliminary or Detailed Site Investigation is undertaken
Petroleum hydrocarbon contamination is suspected
Excavation may intersect former tanks or pipework
Regulatory authorities request confirmation of site condition
Assessment may involve historical review, geophysical investigation, intrusive investigation or soil and groundwater sampling.
Legislative and Regulatory Context
UPSS are regulated through environmental protection, contaminated land and fuel storage frameworks.
In New South Wales, UPSS are addressed under EPA guidance and contaminated land assessment processes, with regulators requiring investigation and remediation where petroleum contamination poses a risk to human health or the environment. Similar regulatory approaches apply across Australia.
How We Can Help
Confluence Environmental assesses underground petroleum storage systems as part of contaminated land and development support services.
Our services typically include:
Identification of current or former UPSS through historical review
Assessment of petroleum contamination risk
Soil and groundwater investigation associated with UPSS
Advice on remediation and management options
Reporting to support planning approvals and regulatory engagement
We focus on providing clear, defensible advice that supports informed decision-making.
Related Terms and Concepts
Contaminated Land
Preliminary Site Investigation
Detailed Site Investigation
Petroleum Hydrocarbons
Groundwater Investigation
Site Remediation
Site Validation