A Dunedin City councillor has offered an apology to the residents of three east Otago settlements who discovered concerning levels of lead have been detected in their water supply for the past six months.
A do not drink notice was put in place on 2 February for Waikouaiti, Karitane and Hawksbury Village after six tests in the past six months showed concerning levels of lead.
The highest level detected was almost 40 times the acceptable limit.
The settlements are just north of Dunedin, but fall inside Dunedin City Council's limits.
Hundreds of residents have sought blood tests since Public Health South offered the service last week.
The lead scare was a topic of discussion at this afternoon's Dunedin City Council infrastructure services committee meeting.
Councillor Andrew Whiley offered an apology to residents at the meeting.
"It's the people of Waikouaiti, Karitane and Hawksbury Village who have been affected by this," Whiley said.
"Personally I'm sorry they went through this. The gutting emotion of that meeting [in Waikouaiti on 5 February] and what these residents went through was really heartbreaking.
"I think the word sorry hasn't been used enough - I haven't heard it used once today - and that, to me, is the most important part; to say we are sorry this community went through this.
"We don't have all the answers for you yet, we don't understand all the issues yet, but we are trying to get to the bottom of this as quick as we can and we want no part of our city - no matter which corner it is - to go through this."
The committee's chairperson, Jim O'Malley, called for calm and said there was much that was still unknown about the source and extent of the lead contamination.
The do not drink notice was brought in under an abundance of caution, and the possibility of false positives leading to the spikes in lead detection in the water supply had not been ruled out, he said.
"This has been an extremely stressful period for the people who have been drinking that water," O'Malley said.
"But a balanced view is necessary here. It is still not clear what has happened and that is why the no drink order was put in place - it's a precautionary order because we don't know what has happened.
"To some extent a rather polarised view has been presented where the worst numbers have made headlines, the word poisoning has made it into the headlines and to counter that you have to come back with other information which may balance that and it may look like when you're trying to create the balanced story you're trying to minimise. There's no way this council is trying to minimise what is going on here. There is no way we are minimising our duty of care to the community.
"We do have to be cautious. We don't have all the information in yet and that's why, for example, I brought up the idea of false positives. I'm not saying they are, but they have not yet been eliminated."
It would take another two or three weeks before there was a clearer picture of what had occurred, O'Malley said.
It was not yet clear when cast iron pipes suspected of contributing to the lead contamination of the water supply in Waikouaiti would be replaced.
The council's three waters manager, Tom Dyer, told councillors work to replace about 5km of old pipe in Waikouaiti would begin very soon but there was no timeframe for completing it.
Work to replace similar piping in Karitane had already begun last year before lead contamination was identified as a problem.
The cast iron pipes used lead joins and it was suspected those old pipes were contributing to the problem, though the source of contamination had not been confirmed, Dyer said.
In response to questioning from councillors, he said the investigation of the contamination was still ongoing.
"We worked pretty hard to plan out a thorough investigation. Some physical steps we've been able to take really quickly and others will take a bit of time. But I've been really pleased with how that's playing out and the thoroughness of results we should be able to pull together by early next week."
The council's chief executive, Sandy Graham, said it was possible some spikes in lead levels, such as the 20 January result showing lead at five times the acceptable level at the Waikouaiti water treatment plant, might never be accounted for.
"The one-off reading in the reservoir it's likely we might struggle to ever know what the cause of that was," she said.
The Dunedin City Council was not specifically testing for lead at the time it discovered the problem but was measuring the corrosivity of the supply's water and using metals as a proxy.
Upon receiving the 31 July test results in mid-August, the council alerted Public Health South and its independent drinking water assessor, and decided upon ongoing testing as the appropriate course of action without informing the public or elected representatives.
The council says during the next 14 weeks, lead tested well below the acceptable limits, except for one result at the Waikouaiti Golf Club on 9 October 2020.
A concerning result showing almost 40 times the acceptable level on 8 December was emailed to a council staff member on 18 December, but they were not opened until the new year as the staff member was on leave at the time and did not check their emails.
Graham was not alerted to the problem until 1 February.
Councillors, including Mayor Aaron Hawkins, were not informed until 2 February - hours before the council went public.
Graham said the handling of the matter was subject to a review and she awaited its findings.