Swimmers are being urged to stay up to date about the water quality at their favourite Canterbury beaches, lakes and rivers.

Health New Zealand | Te Whatu Ora has previously advised against swimming at Corsair Bay | Motu-kauati-iti due to the poor long-term grade and overall health risk from high levels of faecal bacteria. This is especially prevalent during and after heavy rainfall. Environment Canterbury’s most recent weekly sampling result at the bay (taken 13 January 2025) showed levels of contamination that pose a risk to human health.

Dr Ramon Pink, Medical Officer of Health for the National Public Health Service, says “a number of sites within Lyttelton | Whakaraupō harbour, including popular spots like Corsair Bay | Motu-kauati-iti, Rāpaki Bay, Sandy Bay, Diamond Harbour | Te Waipapa and Purau Beach, remain unsuitable for swimming due to the long-term grade and overall bacterial risk from contact with the water at these sites.”

It’s worth noting that no changes in long-term grades have occurred at Lyttelton | Whakaraupō Harbour this year. This means the only spots deemed suitable for swimming are Paradise Beach | Te Wharau), Church | Kaioruru and Cass | Motu-kauati-rahi Bays which remain fair,” says Dr Ramon Pink.

In good news for local swimmers, the temporary warnings that were in place over the last couple of weeks at popular swimming spots Pines Beach, Duvauchelle Bay and Lake Rua in Christchurch | Ōtautahi-have now been lifted.

Warnings remain in place for many of the region’s freshwater sites for faecal bacteria and toxic algae.

When you’re heading for the water, don’t forget to visit ‘Can I Swim Here?’ section of the Land Water Aotearoa (LAWA) website at www.lawa.org.nz toview the latest information.

“Each summer season, Environment Canterbury monitors the water quality of many popular swimming sites around the region for faecal bacteria or cyanobacteria (toxic algae),” says Dr Elaine Moriarty Water and Land Science Manager, Environment Canterbury.

Exposure to these contaminants can be harmful to people’s health. Health NZ will issue a public health warning when toxic algae or faecal bacteria exceeds national thresholds at a site and becomes a significant risk to people’s health.

“It’s really important that you visit the LAWA website to check that it is suitable to swim at your favourite spot before you jump in,” says Dr Moriarty.

“After heavy rain, many recreational water sites are contaminated through rural and urban run-off. As a precaution, avoid swimming in the harbour, rivers, streams, lakes or estuaries for at least 48 hours after heavy or prolonged rainfall, even at sites that usually have good water quality,” says Dr Moriarty.

Water contaminated by human or animal faecal matter may contain a range of disease-causing micro-organisms, such as viruses, bacteria and protozoa, which can cause gastrointestinal, respiratory, and skin infections. People should also avoid eating shellfish from the harbour after heavy rainfall.

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