Rain and runoff from urban and rural properties may have contributed to poor water quality at Akitio Beach, leading to a warning against swimming.

The Horizons Regional Council has been regularly taking samples from the water to test for levels of enterococci and sharing the data on Land Air Water Aotearoa‘s (Lawa) website.

Samples taken last week showed that the water quality did not meet national guidelines which would make it safe for swimming.

The website stated that risk of illness was more than 10 per cent from contact with the water.

People are encouraged to check the water quality before diving into swimming spots. Photo / Alyssa Smith

Horizons environmental monitoring scientist Kelly Le Quesne said enterococci was a naturally occurring bacteria found in the guts of humans and animals, and at high levels could pose a health risk to people when swimming or participating in other water related activities.

Le Quesne said heavy rainfall was often the cause of elevated levels for swim spots.

“This can have a large impact on the water quality at both river and coastal sites, as there is typically more runoff during these rainfall events,” she said.

“In urban areas, the runoff accumulates from roofs, roads, carparks and many other surfaces, picking up various sediments and contaminants.”

That runoff then entered stormwater pipes, which fed into waterways.

Le Quesne said in rural environments, heavy rain could pick up contaminants as it flowed overland into waterways, and at coastal sites, heavy rain and increased river flows could also mix bottom sediments that could release the bacteria into the water as well.

She said when they tested for enterococci at beaches, if a red sample appeared, they were required to take a re-sample to confirm the result, according to guidelines for microbial water quality at marine and freshwater recreation areas.

“If the re-sample also returns a red alert, signs are placed at the beach to inform the swimmers the water is unsuitable for swimming.”

Horizons also worked with Te Whatu Ora Health New Zealand MidCentral, who would decide when health warning signs were required.

Signs would be removed when sampling showed the site was back at amber - amber indicating caution, or green, and safe for swimming.

Samples were taken again at Akitio yesterday but results were not available at the time of printing.

Horizons advise that people should wait 72 hours after heavy or persistent rainfall before getting into the water and be mindful of potential risks when swimming, such as rips at beaches.

They also advise not to swim if the water appeared to be a strange colour.

Information on whether a spot was safe for swimming was also available at www.LAWA.org.nz.