Charmhaven Sewage Treatment Plant upgrade

Project overview

Central Coast Council is delivering a major upgrade of the Charmhaven Sewage Treatment Plant (STP) to support the region’s growing population and protect the health of local waterways.

The $144 million construction works will increase the plant’s treatment capacity and improve performance to ensure it continues to meet environmental and regulatory requirements now and into the future. Construction commenced in March 2026 and is expected to be completed by mid-2028.
 

Project snapshot

• Charmhaven Sewage Treatment Plant (STP) will undergo a major upgrade of the treatment process, which will include a mix of structural, mechanical, electrical and civil works.
• The current treatment plant is at capacity, and current growth requires the upgrading of the treatment plant now. The upgrade will also cater for future growth and allow for further future expansion.
• Central Coast Council has enlisted BMD to undertake the project. It is anticipated approximately 20% of the contract value will be delivered through local suppliers and contractors, providing a boost for local businesses and industry.
• Site establishment commenced in March 2026, with expected completion around mid-2028.
• The project is funded through Council’s long-term financial plan and will be supported by future revenue under the Independent Pricing and Regulatory Tribunal (IPART) pricing determination, including contributions from developers. 
   

Project details

The Charmhaven STP plays a critical role in treating sewage for the northern end of the Central Coast. As the region continues to grow, the existing facility requires upgrading to:

• support increased demand from current development
• ensure ongoing compliance with environmental regulations
• protect public health and the surrounding environment
• provide capacity for future expansion as needed.

Upgrading the plant now will help ensure reliable sewerage services for the community well into the future.

Project scope 

The project includes a comprehensive upgrade of treatment processes and supporting infrastructure across the site to:

• increase treatment capacity to service up to 75,000 Equivalent Persons (EP), with provision to expand to 150,000 EP in the future
• improve operational performance and reliability
• enhance environmental outcomes at the Norah Head Ocean Outfall
• integrate modern electrical, control and monitoring systems

The existing treatment plant will continue operating safely while construction is underway.

Timings

• Construction commenced: March 2026
• Construction completion: expected mid-2028

Some commissioning and finalisation activities may continue beyond this timeframe, subject to construction progress and weather conditions.