Blenheim’s water needs to be chlorinated by the end of the year, but finding the land has been an “issue” for the council.
Taumata Arowai, the regulator of water services for New Zealand, has directed the Marlborough District Council to install residual disinfection in the water supply network.
But the only way to achieve that is through chlorination, which is already in water supplies in Picton, Renwick, Seddon, Havelock, Wairau Valley and Awatere rural.
And the project would require a new building for the water treatment plant.
Blenheim and properties on the Riverlands industrial water supply were the only places in Marlborough that did not have a residual disinfection, council’s operations and maintenance engineer Stephen Rooney said.
Rooney said the council had not previously chlorinated the water supply because it legislatively did not need to, and it was the community’s desire not to.
“There are many [councils] around the country that have made that choice, historically,” he said.
“But as a result of the Havelock North inquiry, the legislation has been changed and we are all now required to have that residual disinfection.”
The inquiry was ordered after the Havelock North drinking water supply was contaminated in 2016 with a bacteria called campylobacter which caused widespread illness.
The inquiry made 51 recommendations on how to keep drinking water safe for New Zealanders which included the universal treatment of drinking water and tougher laws and regulations so standards could be strongly enforced.
“I've fielded some calls from concerned customers or members of the community about chlorinating a supply that they consider is not warranted,” Rooney said.
“But there are risks inherent with operating a network that doesn't have chlorine or a disinfection component within it.
“Contaminants get into the network through broken or damaged pipes.”
In Marlborough, the council’s 2024-34 long-term plan had budgeted just over $4m for chlorination and “other treatment improvements” of the Blenheim supply.
A report that went to full council in February said obtaining land for chlorination was an “issue” for the central water treatment plant in Blenheim.
Rooney said the design for the project was being reviewed to see it the council could “create space”.
Chlorination for the Riverlands supply was planned to be installed with its new treatment plant, during 2024-2025.
The report said the chief executive had proposed the council employ an additional project engineer so that drinking water projects could be advanced.
The chlorination budget was subject to sign-off under the council’s long-term plan.
That plan included a $4.6m budget for new wells in north Blenheim increase the resilience and capacity of the supply.
Budget of $17m was also in the plan for universal metering in 2028-30.
Submissions for the plan would close at 5pm on May 13.
A council spokesperson said the council had received 97 submissions on the plan by May 8.