Residents in the Northern community of Ruakaka are without water as the local treatment plant has become contaminated.
In a statement on Tuesday, the Whangarei District Council warned residents in Bream Bay and Waipu to conserve water as they work to bring the treatment plant back to full production.
The treatment plant has had to dispose of all treated water after the filters became cloudy.
The council believes the cause of the problem is something taken in from the plant's two sources, the Wilsons Dam and the Ruakaka river.
"Last night we were taking water from both sources and believe that we took something into the plant from the Ruakaka River that upset the treatment processes at that plant.
"Since then the plant has been shut down and we are trying to recommission production as quickly as possible," the council said.
Wilsons Dam has been inspected and the council would continue to investigate the cause of the issue.
They are hoping to have the plant up and running by the end of the day.
Until then, residents are asked to avoid unnecessary water use, including watering gardens and playing with water outside.
Take your Radio, Podcasts and Music with you