by Simon Hendery, originally posted on February 3, 2017

Napier’s water supply has recorded a second positive result for E.coli but authorities say the bacteria is present at “the very lowest” detectable level meaning the city’s tap water remains safe to drink.

Napier City Council began chlorinating its water supply on Thursday after receiving a positive indicator test for E.coli in a sample taken from its Enfield Road reservoir as part of routine testing carried out on Wednesday.

The results of a second round of tests on Friday again indicated the presence of E.coli in the council’s Enfield Road reservoir but showed all other parts of its water network testing were clear.

The council said the positive test was showing “the very lowest E.coli reading detectable” and that the source had been isolated to one tank of the two housed at the the Enfield Road reservoir.

The council’s manager asset strategy, Chris Dolley, said the larger of the reservoir’s two tanks has returned consistently clear results while the smaller tank had returned the positive E.coli reading.

The council had shut off the smaller tank and it would “not be used for city water supply until further notice”.

Under national water standards, chlorination continues until three negative E.coli tests are returned, meaning it would continue at least through the long weekend. However the council was installing a chlorine-free tap at Taradale Park.

It said an investigation into the source of the E.coli contamination was underway.

“Obviously we’re very surprised by the outcome of the test, and we’ve shut down the tank while we discover the source,” Napier Mayor Bill Dalton said.