A burst wastewater pipe in Porirua sent wastewater into the stormwater network and Porirua Harbour early Monday, prompting public warnings, water testing and traffic disruption on Tītahi Bay Road.
Wellington Water said crews responded about 2.30am on May 18 to an overflow at the corner of Prosser Street and Tītahi Bay Road.
The overflow was stopped after pumps were isolated, but Wellington Water later confirmed there had been an earlier discharge into the stormwater network.
The volume of wastewater that reached the harbour is not yet known.
Warning signs have been placed at the initial outflow into Porirua Harbour, and water quality sampling has been scheduled.
People are being urged to check LAWA before swimming or entering the water near the affected area.
By Monday afternoon, excavation had been completed and the fault in the pipe had been identified.
Wellington Water said the discharge remained fully contained at the leak site and there were no further environmental impacts reported.
A bypass has been diverting wastewater flow to the new Porirua Central Wastewater Storage Facility, which is being used operationally for the first time.
The facility can store up to seven million litres of wastewater and release it gradually back into the network for treatment.
Repair contractors assessed the damaged pipe on Monday and were expected to begin repairs in daylight on Tuesday.
Traffic management remains in place, with the left southbound lane of Tītahi Bay Road closed overnight.
Wellington Water said the work area had been made safe and would be monitored overnight, with checks also in place at key manholes for any further overflows.
The incident has been reported to councils, mana whenua iwi, public health agencies and environmental monitoring agencies.
Residents can check LAWA for swimming updates and follow Wellington Water’s website or social media channels for further repair information.