Takapuna beach gained the all-clear last night after a murky start to the 2018 swimming season caused by an overflowing stormwater drain.
The beach was deemed a no-swim zone for just over 24 hours, after lifeguards cleared the surf at the popular Auckland hot-spot on the afternoon of New Year's Day due to elevated pollution.
On Tuesday evening the beach had been classified as meeting national guidelines with a "very low risk of infection" by a council website Auckland Safeswim.
Lifeguards initially believed the contamination was raw sewage, but a Watercare spokesman has since confirmed it was not a wastewater overflow, and was not related to its network.
He said after a heavy downpour of rain, foamy water had flowed from a stormwater outfall, and tests of the water did not show signs of sewage contamination.
Subsequently Auckland Safeswim website deemed the beach was high risk, and there was an "elevated health risk due to poor water quality; temporary no-swim warning in effect".
On Tuesday swimmers still ventured out into the contaminated waters despite the no swim warning still being in place.
Some of those the Herald spoke to were angry there were no clearer signs warning people about the recent pollution.
At least 30 people, mainly children, were in the water when the Herald visited the beach just before midday yesterday.
Tasigrace Pace, 18, from Otahuhu, said her family found out about the pollution issue after the children had gone in to swim.
"If the kids get sick or anything, then we will definitely take it up with council," Pace said.
Priya Rajagopalan, a visitor from the United States, said her family was told by an elderly couple about the risk.
Rajagopalan, a mother of two children aged 4 and 14, said the family had originally planned to spend half a day at the beach.
"The kids have been terribly disappointed."
Lifeguard Dan Lee said a sign warning people of the water quality was put out at noon yesterday and would remain until 7pm.
Martin Neale, technical lead for Auckland Council's Safeswim system, acknowledged there had been a "little bit of a gap" where no signage had been set up on the beach.
That was because the signs were put out by and managed by surf lifeguards, who didn't start patrolling until midday.
A large digital sign was planned to be installed at the beach by the end of the month.
But Neale said the Safeswim website was designated to be peoples' primary source of information.
"We've spoken to colleagues in Melbourne who have told us that once people have made the effort to drive to a beach, they are going to go in the water anyway, so what we are trying to do is capture people before they drive there."
The website provides water quality forecasts and information about health and safety risks at 84 beaches around Auckland.
Takapuna was one of a number of Auckland beaches that was considered unsafe for swimming, though these change periodically.
Meanwhile Auckland mayor Phil Goff has proposed a targeted rate of $1.30 a week per household which would be used solely for improving water quality.
Herald readers have mixed views on paying to keep the beaches clean. Ali Herring said beaches were part of the Kiwi culture.
"Why be a Kiwi if you can't swim at the beach? I can't wait for them to start the levy."
Graham Alder was happy to pay to keep the beach, though argued what he was paying in rates should cover that already.