How clean are our beaches?

Swimmers play in the sea at Long Bay Beach. Photo / Janna Dixon

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It's just as well constant wet weather has driven Aucklanders from the beach - more than a third of the region's most popular spots have failed water quality tests since monitoring began in November.

Auckland Council monitors 63 beaches weekly and results released to the Herald on Sunday show 26 of them have tested above recommended lev-els at least once this summer. Ten sites were so bad they prompted a red flag on the council's three-tier reporting system: meaning the erection of signs recommending no swimming. However, bans are not compulsory and the Herald on Sunday this week found dozens of people swimming despite warnings.

Signs have gone up at Milford, Long Bay, Browns Bay, French Bay, Fosters Bay, Karekare and lagoons at Piha, Piha North, Karekare and Bethells. They remain up at Karekare beach and lagoon.

Beaches at Laingholm and Te Atatu triggered the second-highest warning level, amber, five and four times respectively in November and December. An amber flag prompts daily testing of the water.

At Long Bay on Thursday, David Billinghurst and stepson Alex Withers were swimming despite the red-flagging. "If it looks bad, I won't swim," Withers said, "but generally I'll ignore [the flags] and just see if other people are swimming."

Long Bay got the all-clear on Friday when new test results came through.

The rain that has disrupted the holiday season is generally to blame on the Shore, causing sewerage systems to overflow into the sea.

"You should be able to come down for a swim and not wonder 'did it rain last night'?" Billinghurst said.

Also amber-flagged this week were Little Manly, Red Beach and Stanmore Bay. They need re-testing after registering enterococci levels of more than 140 per 100ml.

Whangaparaoa resident Rachel Grant was with her four children at Stanmore Bay, unaware tests showed it was one of the dirtiest beaches this week.

"We do go swimming every day. I took the kids over to the rocks and you can see the foamy water." Grant and the children, aged from 5 to 11, noticed the water stank.

Auckland Council senior pollution response officer Matthew Harrex said water samples were collected by helicopters skirting the coasts. Flights were usually on Tuesdays to allow for any re-tests to be carried out before the weekend beach rush. The findings are published on the council's website and follow-up tests are carried out manually.

At least Auckland beaches are tested. Environment Waikato, the regional council responsible for beaches in the popular holiday spots on the Coromandel Peninsula, has scaled back testing, which is now limited to estuaries.

Whangamata resident and veteran surfer Paul Shanks said that was short-sighted.

"Today at Whangamata, we're suffering the same thing that Mairangi Bay, Torbay and to an extent Takapuna beach suffer," he said. "Fresh water mixes with the excess overflow from the sewerage and it gets washed out on the beach."

In the Bay of Plenty, samples are done at 15 beaches a week during summer. The regional council's science manager, Rob Donald, said as far as he was aware, there were only warnings out about shellfish consumption in some spots.

In the Far North, mayor and avid surfer Wayne Brown said the main water quality problem his region faced stemmed from soil erosion rather than sewage overflow.