At high levels, it is a health risk to people swimming or participating in other water-related activities and can cause urinary tract infections, endocarditis, bacteremia and wound infections.
Swimming was prohibited at the beach for the same reason in November 2022.
Horizons environmental monitoring scientist Ian Hurst said high rainfall often came with high faecal bacteria indicator numbers.
The resample would confirm whether there was an ongoing issue at the beach, he said.
“If the next one comes back and it’s good to swim, we can put it down to being most likely weather-related.
“If we have an ongoing issue, that’s when we get slightly more concerned about other septic tanks or discharges.”
Hurst said Horizons put a lot of work into the Kai Iwi catchment and the Ototoka and Mowhanau streams, including freshwater planting, fencing and communications on best farming and septic tank practices.
Earlier this month, he “highly discouraged” swimming at Mowhanau, Ototoka and Kai Iwi streams because they had a history of poor water quality.
Hurst said Kai Iwi Beach was a popular spot - “I love swimming there” - and Horizons was working as fast as it could to get it reopened.
“The lab turnaround time is about 48 hours from when they receive the sample,” he said.
“They would have received it this morning [January 31] so hopefully we’ll get the results out by Sunday at the latest.”
A Horizons spokesperson said Kai Iwi Beach was generally safe for swimming.
“During the past five years, 79% of the tests we’ve done have been in the green zone [clear to swim] and 9% have been in the yellow zone [swim with caution],” they said.
“That ratio is similar to other beaches in the region.”
Updates on water quality at Whanganui swimming spots can be found at lawa.org.nz.
Mike Tweed is a multimedia journalist at the Whanganui Chronicle. Since starting in March 2020, he has dabbled in everything from sport to music. At present, his focus is local government, primarily the Whanganui District Council.
