Council now legally required to chlorinate drinking water

Government drinking water regulator Taumata Arowai has declined Waimakariri District Council’s first drinking water chlorine exemption application.

This sets a precedent in our exemption application process, and all public water supplies are now required by law to be treated with chlorine.

This means, we will continue chlorinating Cust, Woodend-Pegasus and Kaiapoi supplies and start chlorinating Rangiora, Waikuku Beach and Oxford Urban supplies.

Going forward all supplies will be chlorinated, unless and until an exemption application is granted by Taumata Arowai, as required by law.

The Council has pushed strongly for water in Waimakariri to remain unchlorinated.

We made submissions on the new drinking water standards at Parliamentary Select Committee and pushed Taumata Arowai to allow our supplies to remain chlorine-free while exemptions were being considered.

When the draft decline for the Cust supply was received we challenged the decision and met with Taumata Arowai’s new Chief Executive to again push Waimakariri’s preference for unchlorinated water.

Taumata Arowai have now released their final decision for Cust and informed the Council we must now chlorinate all water supplies.

Waimakariri is the only remaining Canterbury council operating unchlorinated water supplies. In fact, most public drinking water supplies in New Zealand are chlorinated.

We know the community preference and will continue to work with Taumata Arowai to determine a path forward where our drinking water can be chlorine-free. However, this is expected to take a significant amount of investment due to new high standards.

We will keep the community informed. Once we have further information, we will consult further with the options we have.

Below we detail the process we have undertaken to date and cover off many of the questions residents may have about this change in our District’s drinking water delivery.

You can find a link to commonly asked FAQs here.

Taumata Arowai – The Drinking Water Regulator

Taumata Arowai took over water regulation from the Ministry of Health in November 2021. Along with the new regulator, new higher drinking water standards came into effect that required public drinking water supplies to have a Drinking Water Safety Plan (DWSP) in place as well as residual disinfectant, such as chlorine - unless awarded an exemption.

Waimakariri’s Exemption Applications

The Council submitted six exemption applications for our urban supplies of Rangiora, Kaiapoi, Woodend-Pegasus, Oxford Urban, Cust and Waikuku Beach.

Exemptions were not sought for restricted/rural schemes as these have always been chlorinated due to an increased risk profile with these supplies.

What’s happening with my supply?


What’s happening to my water supply?


  • Water   has been chlorinated since November 2020.
  • No   immediate changes.


  • Pegasus   has been chlorinated since it was first established.
  • Woodend   has been temporarily chlorinated from February 2023 due to low levels of   organic material being detected.
  • No   further changes.


  • Temporarily   chlorinated from February 2023 due to low levels of organic material being   detected.
  • We   are now legally required to continue to use chlorine.
  • No   further changes.


  • Chlorine   to be introduced from 14 November.

Waikuku Beach

  • Chlorine   to be introduced from 7 November.

Oxford Urban

  • Chlorine   to be introduced from 31 October.

Restricted supplies: Oxford Rural No 1, Oxford Rural No 2, West Eyreton, Poyntzs, Summerhill, Ohoka, Fernside, Garrymere, Mandeville.

  • All   these restricted rural supplies will still be chlorinated. It will not be   possible to obtain exemptions for these supplies particularly due to the   onsite holding tanks.

As the Cust exemption application was declined by the water regulator Taumata Arowai, the Council will be progressively introducing chlorine over the coming weeks.

Waimakariri is the only remaining Canterbury council to not introduce chlorine into all its public water supplies.

Our intention is to work through, with Taumata Arowai, the investment options that would improve the prospects of obtaining a chlorine exemption in the future and report back to the community about the nature and cost of additional investment required.

Our Water Supplies Are Safe

Waimakariri is fortunate to have pure and safe groundwater. The Council has a history of providing safe drinking water and complying with drinking water standards.

The safety of our water has not changed. It is a change in law, and higher standards and regulations, which require the Council to chlorinate public water.

We must now meet the new requirements in the pipework and delivery system to achieve exemptions in the future. However, no exemptions have been obtained across New Zealand to date.

Investment in Water Infrastructure

The requirement for chlorination is not due to the water quality from source, especially once we have completed our roll out of UV treatment for all supplies. It is representative of the risks of nasties, such as microorganisms, getting into the supply through the network – pipes, fittings, treatment barriers for example.

Over the last 20 years we’ve invested over $100m in water infrastructure which is high quality and have a planned programme to ensure it stays this way. We have a 100-year strategy to fund these assets and a further $41 million is allocated in the Long-Term Plan to support drinking water safety upgrades (such as UV treatment).

New regulations

The Council has always been supportive of the new water regulator (despite our opposition to the previous Government’s Three Waters restructuring policy). It is essential that we have safe and secure drinking water.

We know our water sources are amongst the best in the country and will continue to invest in our water infrastructure to pursue a pathway to chlorine-free water. We will keep the community informed about how we are progressing.

Three Waters Reform proposes the restructuring of ownership of community water assets and is separate entirely to the legal requirement to meet drinking water standards.

Council has advocated for our community

The Council has done everything it can to support the communities strong wish for chlorine free water. The Council made submissions on the new regulations to the Parliamentary Select Committee and has met with Taumata Arowai officials, including their Chief Executive, on several occasions to reiterate our programme of investment and the fact our residents strongly desire unchlorinated water.

This was considered as part of the exemption process and while the exemptions were being considered Council supplies were allowed to remain chlorine free.

Following the Cust decision being released, we are no longer able to run drinking water supplies without chlorine being added.

The Council has done everything we can for our public supplies to remain chlorine free. We will continue to pursue what level of investment will be necessary to achieve chlorine free water and discuss this with the community.

Chlorine levels

When we must use chlorine we are doing so at a rate of around 0.5 parts per million (a concentration of about 0.00005%), which is a tenth of the maximum allowable level. Another way to think about this is one teaspoon of chlorine per 10,000 litres of water.

This is within the healthy level for drinking water recognised internationally, and we are confident about our water safety.

Despite this, the taste and smell can be noticeable when chlorine is first introduced (until the system stabilises) and we appreciate this may concern some residents.

We will continue to pursue a pathway to exemptions

The Council will continue to work with the drinking water regulator, Taumata Arowai, to determine a path forward where our drinking water can be chlorine-free. However, this is expected to take a significant amount of investment which we would need to engage with the community on through future Long Term or Annual Plans.

Where can I find out more information?

As this is a big change in our water delivery, we expect residents will have questions about it.

We ran a series of drop in sessions earlier this year in May to talk about the new regulations and have put together answers to some of the frequently asked questions at

Should you have any questions please get in touch via 0800 965 468 (0800 WMK GOV) or email We will keep the Council website updated with the latest information.