Kerikeri's new sewage treatment plant will open about seven months later than expected after some of the plans had to be redrawn when a new construction site was chosen.
Originally the new plant — the Far North District Council's biggest infrastructure project to date — was to have been completed by the end of this year.
Kerikeri households and businesses are now expected to be able to connect to the new wastewater plant by the end of July 2020.
Council infrastructure manager Andy Finch said large, complex projects were often delayed by unforeseen issues.
"In this case, the new treatment plant was to be built in a disused quarry, but another more suitable site was selected after initial plans were drawn up."