Auckland's beaches are so dirty that ocean swimming events are now regularly being cancelled.
Organisers say unless something is done soon, such events may be a thing of the past for the city.
Surf life savers monitor the swims, but are refusing to oversee any event at a beach that is not safe to swim at..
There are currently 25 no swim notices in Auckland - nearly 40 percent of all monitored beaches. Of the no-swim notices, 16 are long-term with no end date.
Takapuna Beach Series organiser Nick Carroll said in 12 years of running the series, he had previously only cancelled two swims.
But in the last four months he has had to can six events because of water quality.
"It's basically ruined the image of the beach series," he said.
"People only have so much time to spend doing recreation [and] they may not bother with the beach series where it's 50-50 each week whether it's on."
Despite only a small amount of rain in the past 24 hours, Takapuna beach was listed as unsafe on Auckland Council's Safeswim website today.
The no swim notice was likely because about 20mm of rain fell on Monday, with one bout of rain now meaning no swimming for three days.
Mr Carroll said he had had enough.
"It's beyond belief that [the council] could let it become [like] this," he said.
"All they do is blame the councils before them for what's happened, but ... they're still the council and they're what's caused it because of their lack of funding [for] infrastructure."
The writing was on the wall for ocean swimming, he said.
"A lot of people may move away from ocean swimming as a result of what Auckland Council has done here, or hasn't done."
Fulton Swim School owner Daniel Fulton has held a triathlon for hundreds of eight to 12-year-olds since 2006 but, because of poor water quality at Clark's Beach in Manukau Harbour, has had to turn this year's event into a duathlon.
"We had all the approvals to use Surf Life Saving New Zealand but because of the red zone, it's their health and safety policy to say, 'Hey ,we can't swim there safely so you're going to have no life guards.'"
Surf Life Saving New Zealand services manager Allan Mundy said it would be irresponsible to allow lifeguards to patrol the event.
"The guys make their choice whether they want to participate or not, and that puts our lifeguards at risk."
He questioned whether water quality had declined or if testing had just improved.
Regardless, it was affecting the organisation's operations too.
"Even on the beachfronts, the guys can't go out and train regularly."
Auckland Council declined to be interviewed but acknowledged in a statement that Auckland was suffering because of underinvestment in water infrastructure.
A proposed new targeted rate of about $60 a year per household would allow the council to build in 10 years what would otherwise take 30, it said.
Aucklanders can have their say on the proposed rate until 28 March.