Four Auckland beaches had "do not swim" advisories in place for more than half of last summer. Photos / Anna Heath, Brett Phibbs
For many Kiwis, Christmas marks the start of beach time – but if you’re in or around Auckland, it pays to check before you swim. Here is the Herald’s guide to the dirtiest and cleanest swimming spots in the city.
Eight of Auckland’s beaches had advisories against swimming for more than 25% of last summer.
Judges Bay in Parnell was the worst – rated unsafe for the whole summer – and several other well-known city beaches were frequently unswimmable, including Algies Bay and Herne Bay.
The cleanest beaches, where no swimming warnings were issued, included Devonport on the North Shore and West Coast favourites Karekare and Muriwai.
The beach ratings come from Safeswim, an Auckland Council tool that uses real-time data on rainfall, wind and other environmental factors to simulate water quality at the city’s beaches.
It issues colour-coded flags that indicate the risk of getting sick due to faeces in the water.
Black “do not swim” warnings, the highest level of warning, are issued when wastewater has been detected.
Lower alert levels, such as red flags, advise against swimming.
Due to poor water quality, 17 swimming spots have permanent advisories against swimming.
Judges Bay spent all of last summer under a black warning, which remains this summer because of damage to the wastewater network sustained during storms in 2023 (Auckland Anniversary and Cyclone Gabrielle).
The damage has been repaired, but wastewater from private properties is being discharged into the stormwater network, which drains into the bay.
“These issues are currently being investigated and repaired to allow the removal of the black pin as soon as possible,” Auckland Council Safeswim principal Holly Foreman said.
Other swimming spots with the most frequent water quality flags last summer (November 1, 2024, to April 30, 2025) were Kawakawa Bay, Surfdale and Algies Bay.
Home Bay on Motutapu, Te Tinana (Wilson’s Beach) in Hobson Bay, and Herne Bay also feature on this list of the 10 beaches with warnings for the greatest number of swimmable hours.
One of the main causes of the warnings is sea bather’s eruption, a rash caused by certain sea anemones and thimble jellyfish.
Last summer, plenty of Auckland swimmers reported getting the rash and the council is warning the same thing could happen in the coming months.
“As sea temperatures rise coming into summer, it’s quite possible Auckland could again experience sea bather’s eruption this year, similar to last summer.”
Foreman said not swimming in the shallows for extended periods and changing out of swimwear as soon as possible were advised to avoid getting bitten.
Slimy algae also threatens beachgoers’ swimming experience, with blooms of the cyanobacteria Okeania spp possible this summer.
Foreman said no concern was needed for the algae, but the council has advised people to avoid touching it because skin, eye and respiratory irritation were possible.
The table below shows Auckland’s cleanest beaches, where no warnings were issued last summer.
Other clean spots include Piha South Beach, Bethells Beach, Waiwera Beach, Parakai Beach and Palm Beach, all of which had less than 1% of their swimmable hours under a warning last summer.
Watercare had invested $8 billion to build and upgrade wastewater infrastructure, head of wastewater Jon Piggot told the Herald.
“Our $1.67b Central Interceptor project will go a long way towards cleaning up Auckland’s central beaches and waterways, reducing wet-weather overflows by about 80% in its catchment area when it is completed in late 2026.”
The super-sized tunnel is the largest wastewater infrastructure project in New Zealand history.
It will connect with combined stormwater/wastewater networks in older central suburbs and take flows to Māngere Wastewater Treatment Plant for processing.
The tunnel will run from Pt Erin in Herne Bay all the way to the treatment plant.
Meanwhile, a sewer upgrade, set to finish in 2028, would bring real results to Herne Bay and St Mary’s Bay, Piggot said.
Herne Bay regularly sees wastewater overflow; last summer it was under a black warning for 19.3% of swimmable hours.
Overflows have improved around the Tāmaki River, Point England Reserve and Ōmaru Creek, with investment into two pump stations and a sewer.
Between July 2024 and June 2025, no overflows were recorded at Point England Reserve and Ōmaru Creek.
In that same period the year prior, 29 overflows were experienced in that area, Piggot said.
Watercare categorises wastewater overflows into two types: dry and wet.
The former is when blockages cause the wastewater network to overflow, while the latter is when rain overwhelms the network.
Blockages resulting in dry overflows are often caused by oil and fats being poured down the drain or products such as wet wipes or sanitary products being flushed down the toilet.
Watercare spent about $5.5m a year cleaning up overflows caused by such blockages, said Piggot.
A multitude of factors causes wet overflows, including stormwater getting into the wastewater network through private gully traps, downpipes that drain into the network, ageing pipes, and manholes that are not watertight.