Summer water quality good for swimming most of the time, but not after heavy rain

Monitoring data from last summer made available by Land, Air, Water Aotearoa (LAWA) reveals outdoor swimming spots in New Zealand have good recreational water quality most of the time, but project scientists recommend avoiding the water for 2-3 days after heavy rain.

Last summer the popular online tool ‘Can I swim here?’ was used by over 100,000 Kiwis. Hawkes Bay Regional Council Principal Scientist Anna Madarasz-Smith is the ‘Can I swim here?' Project Lead and explained the 2017/18 results, “Looking at all the recreational water quality data collected by regional council scientists from our rivers, lakes, and beaches last year, we see 80 percent of results are green, meaning the water was suitable for swimming.”

‘Can I swim here?’ is now live again on the LAWA website (LAWA.org.nz/swim), ready for another season helping families and holiday-makers choose the best summer swimming spots based on the latest water quality results.

“Through ‘Can I swim Here?’, we’re giving people access to reliable and up to date water quality information, so they can swim in the great outdoors with confidence.

“In addition to water quality, there’s lots of extra info that will help keep families safe including local weather, tides, surf, water temperature, flow-rate, and whether the site is patrolled by lifeguards. ‘Can I swim here?’ also lists site recreational activities and facilities, so it’s a one stop shop for your day at the beach, river, or lake,” said Mrs Madarasz -Smith.

Among the new features released this summer, the online tool now has a conditions may have changed warning that automatically applies to sites that have recently experienced significant rainfall.

“It’s been an unsettled start to December and there’s more wet weather on the way, so it’s important to remind people to wait two to three days after heavy rain before swimming outdoors. This applies to all sites, even if they usually have good water quality because stormwater run-off can wash pollutants into our waterways,” said Mrs Madarasz -Smith.

Pollutants such as sewage and animal faeces contaminate waterways and swimmers can contract gastrointestinal illnesses, respiratory diseases, and eye, ear, nose and throat symptoms.

The LAWA website uses a traffic light system of red, amber, and green to show the health risk of swimming at a chosen site. Green means suitable for swimming, amber means recreational water quality standards have been met but caution is advised for the very young, elderly, or people with compromised health, and red means the water is not suitable for swimming either because the risk of infection or exposure to potentially toxic algae is too high.

LAWA Chair Stephen Woodhead said while there’s lots of fun to be had in the water this summer, it’s important to communicate risk so people can make the best decision for themselves and their family.

“We want to help keep people safe by opening up the data regional and unitary councils collect through summer recreational water quality monitoring. Whether you’re at home or away for the holidays, LAWA has you covered with data on around 700 swimming spots across the country.

“The extensive information on ‘Can I swim here?’ makes life easier for parents who can check if a place is suitable for their family before they leave the house,” said Mr Woodhead.

LAWA is a partnership between New Zealand’s 16 regional and unitary councils, Ministry for the Environment, and Cawthron Institute.