Protecting communities reliant on groundwater from the risk of leaking underground petroleum storage systems – summary report
Background
Underground petroleum storage systems (UPSS) are an entire system of underground tanks, pipes, valves and other equipment designed to store and handle petroleum products. These are mostly located at service stations, works depots and other forms of industry. It is estimated that there are about 130,000 potential UPSS sites in NSW.
UPSS, particularly older UPSS, have a high potential to leak fuel. A leaking UPSS can contaminate the soil, groundwater and surface water, and indoor air from the build-up of vapours from contaminated soil, posing a risk to human health and/or the environment on-site and offsite.
Communities reliant on groundwater are more susceptible to the risks posed by leaking UPSS. In 2016 at Woolomin and 2020 at Duri, both near Tamworth NSW, fuel leaks from UPSS contaminated local groundwater. The contamination compromised the community water supply. It was costly, both in terms of clean-up and the provision of alternate potable water for the affected communities.
In response, the EPA is checking UPSS in other towns reliant on groundwater for leaks. There are too many UPSS sites to check them all at once so the EPA developed a tool to rank the UPSS sites in order of priority for checking. We have checked the sites that pose the greatest potential risk to human health first.
What we did
- From 2022 to 2024, the EPA identified 16 UPSS sites for checking for leaks. 10 of these sites were inspected jointly by the EPA and the local council. The inspected sites were in Crabbes Creek, Somerton, Stuart Town, Wingello, Tabulam (three sites), Bonalbo, Tarago, and Bonshaw.
- During the inspections we checked for leaks and compliance with the Underground Petroleum Storage Systems Regulation 2019 (UPSS Regulation) and pollution of waters.
- We collected water samples from groundwater monitoring wells on the UPSS sites and local groundwater bores in the surrounding vicinity wherever possible. We had the samples tested for hydrocarbons in a laboratory.
- We found hydrocarbon contamination in water samples from two sites.
- None of the sites complied with the record-keeping requirements of the UPSS Regulation.
- We provided guidance and assistance to local councils to ensure appropriate measures were taken to reduce potential human health and environmental risks from the sites and address compliance issues with the UPSS Regulation. Councils are the appropriate regulatory authority (ARA) under the UPSS Regulation for these UPSS which are all retail service station sites. This means that Councils are the responsible authority for non-compliance with the UPSS Regulation at service station sites.
How we did it
We assessed the risks to groundwater-reliant communities from UPSS using a Spatial Analysis Tool based on datasets of operational UPSS sites and registered groundwater bores. UPSS sites were prioritised for checking based on a range of factors including their proximity to groundwater bores and level of groundwater usage in the area. This identified 16 sites for priority checking. After further assessment and discussions with relevant councils, six of these sites were excluded from further investigation because they were decommissioned, or appropriate actions had already been taken, or the sites were no longer in operation. 10 sites required an inspection.
The joint inspections with the local council aimed to assess compliance with the UPSS Regulation, determine the appropriate regulatory approach for any compliance issues, and identify any ongoing support or guidance needed by the councils.
We sampled groundwater monitoring wells on UPSS sites (where available) and sent samples to a certified laboratory for analysis for Total Recoverable Hydrocarbons, Benzene, Toluene, Ethylbenzene, and Xylenes (BTEX) and other common contaminants like methyl tertiary-butyl ether (MTBE), certain heavy metals, and polycyclic aromatic hydrocarbons (PAHs). MTBE was commonly used as a fuel additive in the past, and PAHs are a group of naturally occurring chemicals found in fuel.
For each prioritised UPSS site, properties within a 250-metre radius with registered or unregistered bores/wells were offered free groundwater sampling. We tested samples for hydrocarbons and surveyed residents about their groundwater use.
What we found
Groundwater monitoring well sampling results
Out of the 10 UPSS sites inspected, six had groundwater monitoring wells. At one site, groundwater was not present in the wells, and two sites had non-functioning wells. We tested groundwater at the remaining three sites and found hydrocarbon contamination at two of them.
The result highlights the need for UPSS site operators to ensure all groundwater monitoring wells are functional and regularly maintained, and to conduct frequent groundwater testing to detect contamination early.
Contamination from UPSS in towns reliant on groundwater should be managed to control human exposure to the contamination and protect the environment. There are also economic impacts from contaminated water sources.
Bores/ wells sampling results
There were no detectable levels of Total Recoverable Hydrocarbons or BTEX in groundwater samples taken from bores/wells located beyond the boundaries of each prioritised UPSS site.
Other non-compliance issues
All 10 sites inspected lacked records for loss monitoring, leak detection, and/or a fuel system operation plan (FSOP). These records are required under the UPSS Regulation as they are an important way to detect leaks early.
Table 1 - Inspection summary of the UPSS project
| Description | Project result |
|---|---|
| Number of UPSS sites inspected | 10 |
| Number of councils involved | 7 |
| Number of properties identified within the sensitive zones | 265 |
| Number of properties surveyed | 179 |
| Number of bore/wells tested | 25 |
| Number of UPSS sites with groundwater monitoring wells tested | 3 |
| Number of UPSS sites with hydrocarbons detected | 2 |
What’s next
Ongoing support to relevant councils
We will continue to support councils as needed to investigate sites prioritised for checking.
Expansion of the project
We will continue the project to check the next lot of prioritised UPSS sites in groundwater dependent communities.