Dozens of Auckland beaches deemed unsafe for swimming have no public warning signs - because the council says they won't make a difference anyway.
The Safeswim website has currently noted sewage overflows at six beaches: Herne Bay, Home Bay, Okahu Bay, St Heliers, Point England and St Marys Bay.
More than 30 more beaches have a "high health risk" no-swim warning in effect.
A Watercare spokesperson told Newshub the 40 "high risk" beaches aren't contaminated by sewage, but instead by stormwater that contains heavy metal run-off from aluminium roofs, animal excrement, pathogens, and diesel.
But Auckland Council Healthy Waters general manager Craig Mcilroy told Newshub that beach users pay "little attention to warning signs at beaches", so they don't put them up.
"Once they have invested the time and effort to get to the beach, they will swim regardless of what signs say.
"We also found people get used to seeing signs, especially when they are part of a cluster of public messages, which means they don't get noticed and lose impact."
Regularly changing conditions also made physical warnings impractical, Mr Mcilroy says, and when the council did bother, the signs were either tampered with or stolen.
But even the 16 beaches on a long-term no-swim warning do not have signs.
Auckland Council collects water quality information from Watercare, MetService and its own monitoring stations to identify contamination levels.
After the weekend's heavy rain, about 50 beaches were closed in the region with elevated levels of sewage, stormwater, diesel and animal excrement.
"We feel strongly that information on water quality and other hazards needs to be delivered before people make the journey to the beach," Mr Mcilroy says.
"We encourage people to visit the Safeswim website before they choose to go to a specific beach, in the same way they would check traffic conditions on Google Maps before setting off on a journey."
A digital sign system, which updates swimming recommendations automatically, is currently on trial at Mission Bay.
The council plans to extend this trial to other high-use beaches.
Signs have also been installed at the 84 beaches included on Safeswim's website, reminding people to check online.