A second water sample taken from outside Christchurch Men’s Prison has returned a clear result, but authorities are continuing to take a cautious approach while testing continues.

As first reported by Chris Lynch Media, Environment Canterbury has been working with Corrections since diesel was discovered near a groundwater bore, prompting immediate concern about potential contamination.

Bottled water supplies have since been provided to residents who may have been affected.

Leigh Marsh, Commissioner Custodial Services, confirmed the result saying the sample collected on Friday 6 June came back clear, marking the first negative result since the contamination scare began.

“The sample taken from the same site on 28 May remains the only positive result from our testing. While this is a good sign, we are still taking a cautious approach and testing will continue,” said Marsh.

The National Public Health Service’s advice to a small group of affected neighbours has not changed. They are still being told not to use their household water for drinking or cooking and to rely on bottled water. Officials said they would continue regular contact with impacted residents to provide updates and ensure they had access to safe water.

Corrections said a new testing and monitoring plan was being developed.

Additional bores are being drilled on site, and the number of testing locations has also been expanded.

“Results from these tests will help indicate the next steps as we work with the National Public Health Service to understand when we can see a safe return to normal,” Marsh said.