Permanent chlorination for district in pipeline?

Tasman District Council is to consult on whether to permanently chlorinate its water supplies for Richmond, Riwaka-Kaiteriteri, Motueka, Hamama and Upper Takaka.

At an extraordinary council meeting on Thursday, held via an audiovisual link, councillors agreed to the consultation.

A staff report on the matter says residual disinfection was one of the recommendations from the Government’s inquiry into the 2016 Havelock

North campylobacter outbreak.

‘‘Having multiple treatments, for example: water source protection, filtration, UV and providing residual disinfection is part of the ‘multibarrier approach’, which is being widely adopted as the standard approach to drinking water treatment around the world,’’ the report says.

Council utilities manager Mike Schruer told councillors that drinking water assessors had said the TDC’s water safety plans would not be accepted unless they had some form of residual disinfection.

The Richmond water supply was ‘‘regularly contaminated’’.

‘‘We cannot guarantee that the water supply is safe without chlorination or some sort of residual disinfection,’’ Schruer said.

The Motueka supply was ‘‘a bit better’’ because there were no reservoirs. ‘‘It comes straight out the ground so there’s one slight less element of risk than we have in the other schemes’’.

‘‘However, there’s always a risk of backflow or illegal connections or work’s done on it that could introduce a contamination to the scheme,’’ Schruer said. ‘‘So without some sort of residual disinfection, we cannot ever guarantee the scheme will always be safe.’’

Councillor Dana Wensley said nothing the council did was more important than delivering safe drinking water.

‘‘I fully support this going out to public [consultation].’’

Councillor Trevor Tuffnell said if the council went out to consultation – at a cost – and then ‘‘some of our constituents decide that they don’t want chlorination, where does that leave us’’?

‘‘Obviously, when you read the inserted report, we do in fact need chlorination so if we get these people who don’t want or are objecting to it, what happens then? Why do we actually need to consult?’’

Schruer said the council needed to consult because water supply was a significant activity, chlorination was a controversial topic and it involved a change to the current level of service.

Community development manager Susan Edwards said when making a decision, the community’s views was one input that needed to be considered.

The council needed to ‘‘weigh up the submissions vs the evidence that you have in terms of public health and to make your decision ... and then explain that to the community’’, she said.

In response to a question from councillor Dean McNamara on how much the ‘‘unbudgeted expense’’ would be for the consultation, engineering services manager Richard Kirby said he would be surprised if it was greater than $15,000-$20,000.

The consultation was planned for mid-year with submissions due to close at the end of July followed by a hearing and deliberations in August, Kirby said.

Tasman District Council has 15 water treatment plants. Of these, 11 are already permanently chlorinated.