Suppliers make progress implementing critical treatment barriers

The Water Services Authority - Taumata Arowai, has been monitoring the progress of 29 council and two government drinking water suppliers as they’ve developed funded plans to implement critical drinking water treatment barriers by December 2025.

In October and November last year, Taumata Arowai advised suppliers with supplies lacking protozoa, bacterial, or residual disinfection treatment barriers of its expectation that by 30 June 2024 they provide a funded plan for implementing these barriers.

Since then, these suppliers have sought to identify cost-effective options to get these drinking water treatment protections in place.

Steve Taylor, Head of Operations, highlighted how critical these barriers are for preventing waterborne illness.

“Council suppliers provide drinking water to 84% of people in New Zealand. Most of these supplies have multi-barrier treatment protections in place.

“For those that don’t, getting these treatment barriers in place is critical as they form the foundation of a multi-barrier approach to prevent people getting sick from their drinking water.”

A multi-barrier approach is a key principle of safe drinking water that has been a regulatory requirement in one form or another since 2005.  

All council suppliers that Taumata Arowai contacted late last year responded by 30 June 2024.

These suppliers have made significant progress toward improving drinking water safety. Critical barriers are up and running at 23 supplies, which are managed by nine councils and provide 85,693 people with drinking water.

Looking at the work still to be done, 11 of the councils contacted are on track to implement barriers at 26 supplies that provide drinking water to 442,835 people.

Five councils are exploring end point treatment solutions (filtration and UV at point of supply) for six rural supplies serving 2,565 people, to ensure they are supplied safe drinking water. One council is exploring a further alternate path to compliance.

Three councils have deferred adoption of their long-term plan until June 2025, so will provide Taumata Arowai with a funded plan by this date and install treatment barriers by December 2025. A further three councils have adopted a long-term plan extension and will confirm their funded plan by 30 September 2024 and install all related treatment barriers by 31 December 2025.

Taumata Arowai is engaging with all suppliers on the information they have provided.

In all instances where a supply lacks a critical treatment barrier, Taumata Arowai has reminded suppliers of their responsibility to ensure their drinking water safety planning includes measures to appropriately manage risks until critical barriers, or an acceptable alternative solution, is implemented.

“It is pleasing to see the progress suppliers have made and continue to make to getting the foundations of safe drinking water in place,” says Mr Taylor.

Advancing a safe water vision

The importance of getting basic drinking water protections in place across New Zealand is clear.

“The lack of a protozoa treatment barrier was identified as a likely factor in the outbreak of cryptosporidiosis in Queenstown last year. It’s also why installing critical barriers is an area of focus for us,” says Mr Taylor.

Taumata Arowai expects that most suppliers will have installed key treatment barriers, or have an Acceptable Solution in place, by 31 December 2025.

“Our vision is ‘safe water every day for everyone | kia tiakina te wai, hei oranga mō te katoa’. But we know we can’t achieve this alone. It takes careful planning and all of us working together across the water sector to make this a reality,” says Mr Taylor. 

“Getting the basics of drinking water treatment in place is a significant step toward a future where everyone has safe water when they turn on the tap.”  

More information

Links to additional information

• Find out more about the multi-barrier approach to drinking water safety: taumataarowai.govt.nz/multi-barrier
• Find out more about chlorine and safe drinking water: taumataarowai.govt.nz/chlorine
• Find out about Acceptable Solutions: Acceptable Solutions | Taumata Arowai

What is a protozoa barrier?

No one safeguard, or barrier, is effective against all types of contamination.

While chlorine can kill bacteria and viruses in drinking water, it doesn’t protect against protozoa.

Protozoa are single-celled parasites, like cryptosporidium and giardia, that can make people sick. But they can be removed from water using some filters or inactivated using ultraviolet light, so that they don’t pose a health risk.

These filters and UV (ultraviolet) treatment tools are known as protozoa barriers because they help prevent protozoa from making people sick.

What is a bacterial barrier?

A bacterial barrier is used during the primary disinfection stage in the drinking water treatment process. It’s designed to remove, kill or deactivate bacteria present in water that’s been collected from lakes, rivers, aquifers or rainwater. The most common bacterial barriers are chlorination, UV treatment, and some types of filters.

What is residual disinfection?

Once water has been treated, it needs to be sent out to people – usually through pipes. Things like damage to drinking water pipes create an opportunity for bacteria to contaminate treated drinking water. So, a small amount of chlorine is also added when drinking water leaves the treatment plant to keep treated water safe as it travels from the treatment plant to people. In the water services sector, this is called residual disinfection.