High levels of daytime traffic will require the majority of contract works to be completed at night.
The works are needed to provide redundancy for the existing mains to cater for future population growth and emergencies.
200 metres of mild steel pipeline with integrated cathodic protection will be constructed in the existing RMS roadway. Part of the main alignment will be secured to the Woy Woy Bay Bridge.
The 16 week project also includes the construction of two reinforced concrete valve pits which will house Pressure Reducing Valves.