Water sampling results

Over the reporting period, all water sampling results were compliant. 

Drinking water quality testing is undertaken by the NSW Health Forensic & Analytical Science Service laboratories. Water samples are collected from sites across the region by Council. These sites are representative of drinking water supplied to our customers. The table below summarises the number of individual tests undertaken for the microbiology and chemistry water quality programs, along with details of any test results not compliant with Australian Drinking Water health-based guideline limits.

Council has strong water quality parameters and critical control points in our treatment process to ensure we meet the needs of the community and deliver quality drinking water under the Australian Drinking Water Guidelines (ADWG). 

Water extracted from our storages

Central Coast Council and Hunter Water Corporation share water supply through the Central Coast/ Hunter Water transfer to leverage on each region’s water supply during drought and operational outages.

The amount of water extracted from our storages is dependent on customers’ demand for water, the transfers between Hunter Water, our long-term storages of water and raw water processing. 

The trend of water extraction is consistent with weather patterns. The demand for water in our community usually peaks during the spring/summer period and drops during the autumn/winter period. 

Water produced for the Central Coast community

The Central Coast water supply has a shared connection to Hunter Water Corporation’s water supply through the Central Coast/ Hunter Water transfer. The water produced by Council is dependent on the demands of our communities. 

Demand for water in our community usually peaks during the spring/ summer months and drops during the autumn/winter period. 

Longer-term, Council’s Water Security Plan looks at our community needs along with the source of our water supply. This will ensure that the Central Coast has a sustainable water supply. 

Number of days that beaches/lagoons are not swimmable (due to breaks or discharges)

Over this reporting period, beach/lagoon closures were only seen to occur in April and May. It is noted that the number of days for beach/lagoon closure is an accumulative total of days, where in the instance of 10 beaches being closed for the same period of 2 days, this would equate to a value of 20.

The high total number of 114 days of closure occurred across April and May, where the Central Coast region experienced significant extended wet weather event. Pollution warning signs remained in place whilst monitoring was undertaken to determine impact and if the source of bacterial contamination was caused impacts upon these locations.

Council monitors our beaches and lagoons through the NSW Beachwatch Program.

Volume of biosolids reused

Biosolids are mainly a mix of water and organic materials that are a by-product of the sewage treatment process. Most wastewater comes from household kitchens, laundries, and bathrooms.

The volume shown represents all biosolids entering Buttonderry Waste Management Facility and biosolids from Woy Woy and Kincumber Sewage Treatment Plants which are applied to land. Some of these biosolids are delivered to a network of farms for land application, carried out under strict biosolids guidelines. The other portion is composted to produce stable composts and soil conditioners.

Learn how to keep our sewerage network flowing and reduce biosolids. 

Number of Environmental Protection Licence (EPL) non-compliances

During the reporting period, Council recorded two (2) instances where the acceptable presence of chemicals in the effluent have been above the allowable limits at ocean outfalls. Our Sewage Treatment Plants operate using a variety of biological processes and equipment to achieve a high-quality effluent that is released to the ocean via one of our three ocean outfalls. It should also be noted that improvement in Council’s exceedance of the allowable limits at ocean outfalls will not be realised until the completion of the current ongoing large maintenance works and the extensive capital improvement projects. 

The non-compliances and high load limits during the period are related to:

• The flow-weighted load for suspended solids coming from Bateau Bay STP (EPL 1942) was trending unfavourably, with key assets having been cleaned to help reduce loading on the final effluent. An improvement in the sampling technique has been identified as a key contributing factor to licence compliance.

• The flow weighted load for total nitrogen discharged to the Norah Head Ocean (EPL 2647) continued to trend unfavourably, primarily due to ongoing issues with the biological removal of nitrogen from Charmhaven STP.

         

Council is continuing to focus on the progress towards the planned sewage treatment plant upgrades, refurbishments, and maintenance activities of the aging process equipment to address the non-compliances. This will help to improve our effluent discharge quality. However, significant improvements in the effluent discharge quality will not be fully realised until the commissioning of major planned plant upgrades and beyond. These upgrades are scheduled for completion in 2027.

Sewage overflows

The number of sewage overflows reported are the combination of overflows from a range of sewerage network assets, including vacuum pot overflows, access hole overflows (caused by chokes), or pump station overflows which can occur in both dry and wet weather events. April and May results were both impacted by significant wet weather events, with results normalising in June as conditions stabilised.

Aging infrastructure across areas of the Central Coast combined with legacy asset materials and construction techniques (for example vitreous clay pipes) will continue to impact results sporadically. Tree roots continue to be a problem in pipelines accounting for most network overflows.

Council is continuing to focus on increasing tree root removal, together with other programs designed to target a reduction in overflows across the entire network. This includes sewer main renewals and relining of larger sewer pressure pipeline and sewer maintenance access hole resealing programs. 

Volume of sewage overflows

Council continues to implement various programs to target a reduction in overflows across the entire sewage pipeline network. Some of these are aimed at finding issues quickly while others focus on long-term change. These include leak detection programs, sewer main renewals and relining, large sewer pressure pipeline renewals and sewer maintenance access hole resealing programs.

The very high volume reported in February 2025 (5,973 kL) was primarily due to a treated wastewater leak from a single 750mm Effluent Distribution Main (5,960 kL).

Elevated results in May were impacted by the wet weather event which increased pressure on our systems across the Central Coast.

* The volume of sewage overflows excludes storm events as there is no method through which volume can be estimated. The graph above only shows network sewage overflows that were reported to the EPA that did not occur during heavy rainfall events.

Number of sewage overflows reported to the environmental regulator

Council is required to report back to one of our regulators (the New South Wales Environmental Protection Authority - EPA) on sewage overflow events. Events reported are primarily those that enter waterways either directly through sewage overflows or indirectly with sewage entering a stormwater system. Factors such as aging assets, increased rainfall and increased usage can all contribute to the number of reportable incidents.

Sewer main breaks and chokes

The number of sewer main breaks and chokes reported are the combination of sewer pressure main breaks and sewer chokes. Sewer chokes occur when something inside a pipe stops it from working properly.

The reported number of sewer main breaks and chokes have predominately been caused by tree roots in the pipelines, accounting for over 60% of all breaks and chokes.

Aging infrastructure across areas of the Central Coast, combined with legacy asset materials and construction techniques (for example vitreous clay pipes) will continue to impact results sporadically. Tree roots create problems in pipelines historically through nature seeking sources of moisture and nutrients that is readily available within sewage.

Council is continuing to focus on increasing tree root removal, together with other programs designed to target a reduction in main breaks and chokes across the entire network. This includes sewer main renewals and relining of larger sewer pressure pipeline and sewer maintenance access hole resealing programs. 

Our community can help by engaging with our Sinkables and Flushables campaign and ensuring only water, soap, and toothpaste go down your sink drains and only flush pee, poo and toilet paper in your toilet.