Wollongong sewage overflows to improve as Sydney Water forced to act

Sydney Water was told to improve its game by the Environment Protection Authority after average wet weather overflows reached between 50 and 60 per ten-year period.

Meanwhile the water utility has been subjected to a mandatory environmental audit after the EPA's patience ran out with the continual sewage failures and the pollution occurring as a result.

The EPA said it suspected Sydney Water's sewage activities were "being carried out in an environmentally unsatisfactory manner and that sewage discharges are due to systemic issues related to management and maintenance".

The audit applies to 23 Sydney Water operations including Wollongong, where three instances of raw sewage flowing across the Wollongong Golf Course resulted in a penalty of more than $1 million. It began in October last year, the month that penalty was agreed.

In Wollongong a separate pollution reduction program has recently been concluded, designed to to bring the rate of overflows back down to the 40 overflow incidents per decade allowed under Sydney Water's pollution licence.

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While four overflows per year might still pose struggles Wollongong for residents, it is an improvement on the six-plus they were getting six years ago.

When large storms have caused flooding north of the Gurungaty Waterway between the CBD and Sydney Water's sewage plant off Springhill Rd, various factors have been blamed for sewage overflow.

These have included people illegally accessing the stormwater system, tree roots penetrating pipes, high tides, and creeks blocked by vegetation and debris.

The Environment Protection Authority said the rolling 10-year average number of wet weather overflows was 65 in 2017, 53 in 2018, 49 in 2019 and 2020, and 50 in 2021.

The Mercury had reported on sewage overflow in south Wollongong as far back as 2012.

An EPA spokesman said the agency would now ensure Sydney Water met its licence conditions.

"To address several years where Sydney Water exceeded its permitted wet weather sewage overflows for its Wollongong system, the EPA added a Pollution Reduction Program to its licence in 2020," he said.

"The program required Sydney Water to complete a range of works by the end of June 2023. This included pipe relining, the modification of emergency relief structures and the construction of additional storage capacity.

"We expect these works to reduce the number and impact of wet weather sewage overflows in the future.

"We will continue to protect the environment and community of the Illawarra by ensuring Sydney Water meets its licence conditions."

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There had been several years of non-compliance with the licence limits before this work was initiated.

Sydney Water said it had spent more then $50 million from 2020-24 to reduce the risk of overflows throughout its operations.

It said there would be more work done if the Wollongong improvements did not succeed.

"Most of the works have been focused on replacing maintenance holes, upgrading our emergency relief structures and relining sewer mains," the company said in a "holding statement".

"Further amplifications will be progressed if the Wollongong system performance does not meet our performance expectations or the requirements of the EPA."

The Mercury asked Sydney Water how many sewage overflows there had been in the years prior, and where pipelines it had "amplified" were located.

The "holding statement" did not answer those questions.

Last October Sydney Water had to pay more than $1 million after the Wollongong Golf Course sewage incidents were blamed on holes in the sewage pipes, known as rising mains.

The July 2020 incident was the worst, with approximately 967,000 litres of sewage flowing about 76m across the fairway, forcing a month-long closure of the northern end of the course. The outcome of the mandatory environmental audit is pending.