Call for all drinking water suppliers to ensure multi-barrier protection

Call for all drinking water suppliers to ensure multi-barrier protection

21 September 2023

Water New Zealand says the suspected linking of Queenstown’s cryptosporidiosis outbreak to the town’s water supply highlights the need for effective multi-barrier protection of drinking water.

Acting technical manager Lesley Smith says around twenty percent of the population in Aotearoa New Zealand is supplied with drinking water that does not provide adequate barriers against protozoa contamination.

“It’s not been confirmed that the Queenstown outbreak is linked to water supply, but we know that there is a risk if water is not adequately treated.”

She says that many suppliers do not have the resources to provide the level of protection needed to ensure safe drinking water that meets drinking water quality standards.

“While chlorine provides effective protection against bacterial contamination, it won’t protect against cryptosporidium.

“This requires alternative measures such as membrane filtration or UV treatment. This adds additional costs and requires technical expertise to install, maintain and monitor the treatment processes.

“Many suppliers, particularly smaller ones, struggle to afford the funding and expertise required to run this level of multi-barrier protection.

“During 2022 there were 164 boil water notices across 36 councils and 87 suppliers – a clear indication that there has been water supply contamination.

“We need to take a long term view about how we can ensure safe drinking water for all New Zealanders that provides equitable outcomes for small communities.

“Clearly, scale is important. Large organisations are more able to fund the infrastructure and expertise to manage the complex multi-barrier protection.

“We know that one in five New Zealanders are supplied with drinking water that does not meet drinking water standards and therefore is not knowingly safe to drink, while another million people receive water from small supplies or self-supplies where there is no information about the water quality they are drinking.”

She says it is important that the new regulator, Taumata Arowai, is adequately resourced to monitor suppliers and ensure better compliance with drinking water standards and that there is a cross-government, multi-agency approach to source water protection.

“Water New Zealand is the industry body for the water community and we will be working to ensure that the experts within our membership are available to support Queenstown Lakes District Council as they work through any issues that may arise, particularly if it is found that the source of the outbreak is from water supply.”