What does the red level mean?

From the SafeSwim FAQ
What is the risk of swimming when a red Highlight is showing?

The health risk posed by faecal contamination in recreational waters is traditionally assessed by monitoring Faecal Indicator Bacteria (FIB). FIBs generally won’t make you sick, but numerous studies conducted by the World Health Organisation, the New Zealand Government and others have established reliably that FIBs tend to indicate the presence of pathogens that can make you sick.

No beach will ever be 100 per cent safe. Microorganisms exist naturally in our environment and it is possible that a swimmer may become ill after swimming at a beach that appears to have good water quality.

New Zealand’s public health guidelines provide a threshold for advising the public when there is an increased chance of them coming into contact with pathogens in the water and becoming ill. The guidelines require the public to be notified when levels of FIBs indicate 1 in 50 swimmers are likely to become ill.

Swimming where a red water droplet is showing on Safeswim means at least 1 in 50 swimmers are likely to become ill.

But contaminant plumes don’t necessarily mix uniformly. It is possible to swim through more concentrated ‘plumes’ of contamination when swimming at a beach where a red water droplet is showing. In these cases the risk of falling ill may be much higher than 1 in 50. In one case in Denmark, nearly half of all participants in the swim leg of a triathlon that went ahead under these conditions fell ill.

There is a consistently high risk of falling ill from swimming at sites with a red ‘no-swimming’ pin (red-coloured swimmer with a cross) – it is greater than 1 in 10 people.

Safeswim follows international and national guidelines designed to provide water quality advice for swimmers close to shore. Activities where people are unlikely to put their head under water – like stand-up paddle boarding, boating and kayaking – or swimming in deep water offshore are less likely to lead to illness.