Construction of the HamNak Water Pipeline was "progressing well", he said, and only "small portions of pipework" were still to be completed.
"We need to finish putting in the final sections of pipework, pressure testing and sterilisation of the pipework and completion of one of the pump stations," Mr Pacey said in an email.
Commissioning of the system would occur before the council started supplying water from the new system.
The Hampden-Moeraki and Herbert-Waianakarua water supplies served a combined population of more than 1300 permanent residents, in more than 820 dwellings, across an area of almost 12,000ha.