A boil water notice has been in place for the greater Greymouth area for the last two weeks as the council continues work to identify the source of bacterial contamination in the water supply.
It cannot be lifted until water regulator Taumata Arowai is satisfied the council has complied with directions.
Mayor Tania Gibson told RNZ's Morning Report programme today the council was still investigating the cause of the problem.
We know what it is but we still haven't really found the problem.
"Because the contamination was so minor, that's why it has really been hard to find."
Gibson said the water had tested clear for five days and, following discussions with the regulator, they hoped information they were providing today would be what is required to lift the ban.
There had been no reports of sickness as a result of the water contamination, she said, and the ban had been incredibly frustrating for the district.
"It's been a very difficult time."
