Council commits to drinking water UV protection

Published on 31 October 2023

Whanganui District Council chief executive David Langford is assuring the community that plans are in place to ensure Whanganui continues to have safe drinking water at the highest standard possible now and into the future.

David Langford gave the assurance at a long-term plan workshop held in October that focused on council infrastructure. Councillors heard that new national water services regulator Taumata Arowai has lifted the bar for national drinking water standards.

Whanganui’s active water bores do not currently require the extra protection of ultraviolet UV treatment as the bores are deep and therefore less vulnerable to contamination, including protozoa getting into the water source. However, this is set to change as new drinking water safety standards come into effect in the future.

Protozoa is the name for a group of micro-organisms that include cryptosporidium (or “crypto”) and giardia and which have the potential to cause serious illness if present in the community.

Scoping and design work was already underway to have UV protection installed as soon as possible, David Langford said. Along with the existing chlorination of the drinking water supply to protect against bacteria and viruses, UV protection would ensure the supply had multiple barriers of protection, including against protozoa.

“The council is taking the initiative to put in the extra protection, and this will mean our drinking water supply will be even safer for our community. Drinking water standards have been raised by Taumata Arowai and we don’t want to be left behind.”

Council senior water engineer Dave Rudolph said there was a robust testing regime in place for the active bores, including significant ongoing monitoring of bacterial organisms (E. coli and total coliforms) that provide an indication of potential contamination.

Investigation by the council into UV treatment to provide even more protection had begun well before the current cryptosporidium outbreak in Queenstown that had resulted in boil water notices for that community, he said.

“We are committed to reducing any risk to our community, and providing multi-barrier protection will put us in the best possible position. We know local authorities around the country are also dealing with these new regulations.”

Dave Rudolph said, “Source protection is the key. We understand where we need to be to meet the new rules and the UV work has been identified in our long-term plan budgets.”