An online check of the water quality should be as much a part of a trip to the beach as sunhats and sunscreen.
That's the advice of Auckland's Regional Public Health Service after unsafe levels of human waste were detected at a popular inner-city beach with many beachgoers unaware of the risk.
Regular council testing revealed water contamination from human faeces, triggering an online alert, but there were no signs on the beach warning swimmers of the danger.
The council says warning signs go up when necessary at Auckland's busiest but it's not feasible to put them at the more than 20 which are prone to contaminated water overflows.
Water quality's not just an Auckland problem, it's an issue confronting councils nationwide as they struggle with population growth and the massive cost of replacing ageing stormwater and sewerage systems.
"Often, not always, after a heavy storm or rain we will see within the first week or so after that an increase in reported gastroenteritis," David Sinclair, medical officer Auckland public health, told 1 NEWS.
Work's underway in Auckland on a long-term, billion-dollar solution that will eventually see all waste water carried to the Mangere treatment plant.
In the meantime, the advice is to stay out of the water for 48 hours after heavy rain and to check the Safeswim website.
But for those who can't stay away, the advice is swim more than 50 metres offshore as the nasty bugs lurk closer to shore.