Napier Mayor Kirsten Wise has admitted making a mistake in public statements about how much her council would invest in Three Waters compared to the government's reforms.
Wise has staunchly opposed the reforms, which will take drinking, storm and waste water assets away from councils and put them into four mega entities across the country.
She is running for a second term at the top job.
Over recent months Wise has, along with other councillors, repeatedly said the council would invest $404 million in improving the city's Three Waters infrastructure over the next 10 years in its long-term plan, and has suggested the government's Three Waters reform would only spend a third of that amount, approximately $130m.
In one instance at a press conference in June, Wise said: "Napier City Council has got $404m in our current long term plan, the government modelling included a third of the investment for Napier."
But the Department of Internal Affairs told RNZ the estimated spend for the next 10 years under the Three Waters reforms for Napier would be $469m.
After questioning from RNZ, Wise acknowledged she had "mistakenly referred" to the wrong figures for these comparisons.
Wise said, when she claimed the government would spend only a third of what the council would, she was looking at data the council had submitted to the DIA on council's intended plans.
Napier City Council had told DIA it wanted to invest $1.7 billion over 30 years, but the figure was based on what it would spend if there were no constraints and was not peer reviewed.
In an email to RNZ, Wise said "confusion has arisen" as she had compared the figure of $1.7b to the government's planned spend, instead of the long-term plan figure of $404m.
The government's planned spend of $469m is less than a third of the $1.7b figure.
Napier councillor Greg Mawson, who is also running for re-election, posted on social media last week saying while the council planned to spend $404m over the next 10 years, the government planned to spend $89m.
But three days later, he updated the post and said, "I had a figure calculated above of $89m, which I could not find the source, so have deleted that.
"End of the day, there are a lot of figures being bandied about by the government, and even those figures will be changed as the council Three Waters team do more investigations working out the state of the pipework," he said.
Water Works in Napier
New water bores commissioned by the council, in an aim to provide the city with less brown, dirty drinking water are close to being completed but have been beset by delays.
They were originally set to be operating by June, but are still yet to be online.
The council said the delays were due to people being off in isolation or being sick, which had affected the whole supply chain.
The bores also needed to go through "lots of testing".
The testing contributed to more brown water coming through the city's taps two weeks ago.
The new bores are now due to start operating later this month.