The Wairoa township water treatment plant is keeping up with upgraded water drinking standards following the unit’s recent Ministry of Health recognition.

The Havelock North water contamination event triggered the Ministry of Health to make some urgent and sudden changes to both the New Zealand Drinking Water Standards and the type of tests currently undertaken by some laboratories, including the Wairoa plant.

The main difference was around changing the E- coli/coliform testing to an enumeration method that identifies the presence or absence of e-coli and total coliforms and counts the most probable number of colonies of e-Coli, or total coliforms, in a particular sample.

Wairoa District Council chief executive Steven May said this was quite a challenge given the relatively short time frame given and involved finding a recognised test and supplier with an approved test method including equipment, updating all the laboratory manuals to reflect the new tests, training staff and having an IANZ audit approve it all.

The change in testing means if there is an e-coli event, testing will indicate how extreme the event is at that point in time, and whether it’s getting better or worse.

No e-coli presence has been detected in the Wairoa township supply as far back as records show.

The water plant’s annual assessment is based on a range of requirements, and additional water sample tests are also carried out by independent accredited laboratories.

The Water production Business Unit carries out water tests every day during the week and on selected weekend days including tests for turbidity, free available chlorine and ph.

All the potable (drinking) water leaving the treatment plant is also monitored by validated instrumentation providing a continuous one-minute interval record of all data which can be accessed in a matter of moments if required.

An outside third-party instrumentation calibration/validation technician also carries out an annual inspection on all associated instrumentation as validation of our internal management processes are meeting the required standard.

The water plant’s on-site recognised registered laboratory provides cost savings to the ratepayers.

In a feasibility study which considered the option of having all the sampling done out of town- the total cost was nearly double that of doing it in-house.

Mr May said having the service run from out of town would also cause issues such as around microbiological samples not arriving at the preferred lab within the necessary 24-hour time frame.

The Council laboratory also carries out water testing for rural schools, cafés, organisations, clubs and members of the public who would have found it more difficult to use an out of town lab for micro tests considering the current timelines for couriers etc

Mr May praised the work of Wairoa’s water production business unit manager Morgan Goldsmith and his team.

16 May 2019

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