Chlorine exemptions: Your questions answered

Government water regulator Taumata Arowai has advised that it will decline Christchurch City Council’s first chlorine exemption applications.

All public water supply networks must be treated with chlorine unless an exemption is obtained. This signals the start of a shift in the way we manage our water supply across Christchurch and Banks Peninsula.

Here, we answer some of the questions you may have about what that means.

What exemptions did you apply for?

The Council always intended to apply for exemptions from residual disinfection (chlorination) on a zone-by-zone basis and started this process in October 2022 with an application for Brooklands-Kainga, as this water zone was identified as having the best chance of getting an exemption due to the quality of infrastructure and groundwater.

We also put in a second exemption application, which is technical and relates to how chlorine is delivered in areas that are already chlorinated. The Council’s chlorination method doesn’t meet some of the Drinking Water Quality Assurance Rules – for example, the contact time requirement, which relates to how long chlorine is in the water before it makes its way into Christchurch’s network of pipes and would require treated water reservoirs at all pump stations.

Why were the exemption applications declined?

Brooklands-Kainga residual disinfection exemption application 

The first application relates to the Brooklands-Kainga water supply zone. The Council applied for an exemption from the requirement to add chlorine to drinking water in the area. We chose this water zone as we thought it had the best chance of getting an exemption due to the quality of infrastructure and groundwater. 

The reason why the draft application has been declined is that the supply cannot currently be operated without chlorination in a way that is consistent with the main purpose of the Water Services Act. 

Summary of reasons for that view: 

• Water supply has no primary treatment barrier eg. UV treatment and therefore doesn’t have a multi-barrier approach. 
• Council’s risk management plans weren’t specific enough to the Brooklands-Kainga water supply and needed more site and system specific detail.  
• Lack of evidence of source water risks and investigations of poor source water quality. 
• Unacceptable level of water loss within network to safely operate without chlorination. 
• Backflow measures are inadequate for a chlorination free supply. 
• Need to provide a more detailed explanation about historical contamination of the supply. 
• Failure to meet other legislative requirements of the legislation and Rule. 

Chlorine contact time exemption application 

The second exemption application is technical and relates to how chlorine is delivered in areas that are already chlorinated. The Council’s chlorination method doesn’t meet some of the Drinking Water Quality Assurance Rules – for example, the contact time requirement, which relates to how long chlorine is in the water before it makes its way into Christchurch’s network of pipes and would require treated water reservoirs at all pump stations. 

The reason why the draft application has been declined is that the supply cannot currently be operated without chlorination in a way that is consistent with the main purpose of the Water Services Act. 

Summary reasons for that view: 

• Exemption can’t be granted while parts of Christchurch are non-compliant with the Act, and Rules. 
• Some of our sources are from shallow groundwater which lack treatment barriers. 
• Our source water risk management plan didn’t identify risks at an individual bore level. 
• Incomplete actions taken where bacterial contamination was detected. 
• Upgrades to our Chlorination treatment infrastructure and some bore heads are still yet to occur. 
• More detail required on giving effect to Te Mana o Te Wai. 

What’s next?

The Council has until late June to provide feedback on the draft to Taumata Arowai, which will then consider the feedback and finalise the decision.

Without an exemption in place, chlorine will be introduced to all water supply zones across the city. This is a necessary step to complying with the Water Services Act and the associated rules and standards for community water supplies.

Unchlorinated areas of Christchurch and Banks Peninsula (approximately 20%) will have chlorine introduced into the water so we comply with the law. The remainder of the city is already being treated with a low dose of chlorine to achieve 0.2 parts per million (ppm) across the network. This is one-fifth of the dose that was used when temporary chlorination began in 2018.

There are some pump stations where we still need to use unsecure wells while we drill new deeper ones, and these are being dosed at 1.0 or 0.5 mg/l, depending on whether the first customer is within one or two minutes of the pump station.

What’s stopping the Council removing chlorine?

New Zealand’s drinking water laws have changed. The Water Services Act 2021 makes it mandatory for water suppliers to add a residual disinfectant – chlorine – to the water, unless they obtain an exemption from Taumata Arowai.

To meet the regulations, the whole of Christchurch and all Banks Peninsula water supplies need to be chlorinated. Not doing so opens the Council up to regulatory action, which could lead to prosecution.

What level of chlorine will be introduced?

Areas where chlorine is being introduced will only receive a low dose to achieve 0.2 parts per million across the network.

When will it happen?

How long will be chlorine be in the water?

We can’t provide a specific timeframe for this, and the picture has changed significantly from in the past.

We’re currently in the process of working through the draft decision to understand exactly what it means for Christchurch and Banks Peninsula water supplies.

We know that there is a huge amount of work required to make our water supplies compliant. What we want to invest in is an issue we need to consider together as a city, and we'll have the opportunity as part of the Long Term Plan 2024–34.

These decisions are draft – will they change?

We have until late June to provide feedback. However, we are not expecting the final decision to change due to the nature of feedback received in the drafts. We’ve also met with Taumata Arowai to discuss the decisions and it is clear there is a huge amount of work required to make our water supplies compliant and eligible for exemptions.

Will you continue applying for exemptions?

We are currently in the process of working through the draft decision to understand exactly what it means for Christchurch and Banks Peninsula water supplies.

We know that to achieve exemptions for many parts of the district, we’d have to make substantial upgrades to our water supply network.

Whether this is something we want to invest in is an issue we need to consider together as a city, and we'll have the opportunity as part of the Long Term Plan 2024–34.

What’s the background to this?

In 2016, the water supply in Havelock North was contaminated with campylobacter. Four people died and 5000 people fell ill.

Following this incident, the Government carried out an inquiry and established the Three Waters Review to look at how to improve the regulation and delivery of drinking water, wastewater and stormwater – the three waters.

We responded to the review by investigating the condition of our below-ground well heads (the source of contamination in Havelock North) and began an extensive improvement programme. An assessment found the well heads assessed did not meet standards and the Drinking Water Assessor advised the Christchurch water supply was no longer provisionally secure.

The resulting loss of the secure status for our water supply, forced us to make the decision in early 2018 to temporarily chlorinate our water supplies. If we had not made that decision, the Medical Officer of Health would have required us to chlorinate. Temporary chlorination of much of the city’s water supply began in March 2018.

The Government continued work to review and make changes to three waters across New Zealand and in late 2021 new legislation – the Water Services Act 2021 - was passed. This established Taumata Arowai - the new water regulator.

The Act makes it mandatory for owners of reticulated water supplies to add a residual disinfectant – chlorine – unless an exemption has been granted by Taumata Arowai.

What about Banks Peninsula’s water?

Banks Peninsula’s water supplies are generally sourced from streams and springs. Surface water sources such as these always run the risk of contamination as they are open to the elements so they need to be treated (through filtration and disinfection barriers, including chlorination) to ensure safety.

In the past, regulations allowed us to supply unchlorinated water if we met standards that demonstrated our water was uncontaminated. Those standards have now changed, and we will no longer be able to meet them.

The Akaroa and Duvauchelle water supplies are already permanently chlorinated. The remaining Banks Peninsula water supplies - Wainui, Little River, Birdlings Flat and Pigeon Bay – will now be chlorinated.

Have the upgrades to the well heads been a good investment?

Yes, it is important work that needs to be completed to improve the security of our water supply.

The work we are doing is best practice and will future-proof the network for Christchurch for many years to come. It also has other benefits as our new above ground wellheads are much easier to access for ongoing maintenance.

How much does chlorination cost?

The current cost is approximately $2.1m per year. An additional $700,000 annually will be required to chlorinate the remainder of the water supply. 

How much has been spent upgrading the water supply since 2018? 

Since 2018 we have invested $60m on water supply improvements related to meeting the drinking water standards. We have also invested an additional $115m in water supply pipe renewals. This work would have happened anyway as part of our renewals programme, but it also contributes to bringing our water supply network up to standard.

None of this work is wasted as it improves the security of our water supply. The work we have done helps to future-proof the network for Christchurch for many years to come.

What are the Drinking Water Standards?

The Drinking Water Standards have been issued by Taumata Arowai under the Water Services Act. They are accompanied by Drinking Water Quality Assurance Rules.

The standards specify:

• Maximum amounts of substances, organisms, contaminants and residues that may be present in drinking water.

The rules specify:

• Requirements that drinking water suppliers must meet as part of their responsibility to demonstrate that they are producing safe water.
• Water quality operational requirements.
• Criteria for demonstrating compliance with standards and demonstrating that MAVs for determinants in the Drinking Water Standards are not being exceeded.

Is chlorine safe? 

Chlorine kills the bacteria that can get into water supplies and spread disease, helping ensure supplies are safe to drink.

Chlorine has been used safely all around the world for about 120 years. It keeps millions of people all over the globe – including in most of New Zealand – safe from waterborne illness.

There are no known health impacts from drinking water treated with chlorine and it is safe for pregnant women to drink. The quality of the groundwater remains excellent and it is tested daily to ensure it is free of bacterial contaminants.

The amount of chlorine dosed into the water supply will be carefully managed to ensure levels of chlorine in the water people drink are minimised. 

What can I do about the taste and smell? 

There are 53 pump stations across the city. While you will be primarily supplied by one pump station, if you are midway between pump stations, sometimes you may be getting the water from one pump station and sometimes the other. The level of chlorine in those pump stations may be different. If you live close to the pump station, the chlorine dose you get coming out of your kitchen tap will be higher than if you live further away.

If you are concerned about the taste, you can keep drinking water in an open jug in the fridge. The chlorine taste will dissipate naturally over a few hours.

Chlorine and any associated by-products can be removed by using a granulated, activated carbon (GAC) filter. These are available from hardware supply stores and water filter companies.

Skin conditions or sensitivity to chlorine?

Chlorine can be an irritant for existing skin conditions such as asthma or eczema. If you feel your skin getting dry or itchy, use moisturiser after having a shower or bath, or if you notice increased skin irritation, asthma symptoms or other symptoms, seek medical advice from your GP. 

Dialysis

There are no known health impacts from drinking water effectively treated with chlorine. The use of filters will mitigate any risks for those on dialysis. This is arranged by Te Whatu Ora - Waitaha Canterbury. 

Cancer

The International Agency for Cancer Research (IARC) does not believe chlorinated water is either a probable or even possible, cause of cancer.

The Journal of the National Cancer Institute acknowledges that “water chlorination is one of the major disease prevention achievements of the 20th century”, and that it “has become the principal means of effectively reducing waterborne enteric diseases”, which the World Health Organisation has stated account for a significant number of deaths every year, even in developed countries.

Looking after pets and fish

Treated water is safe for household pets such as cats and dogs to drink.

If you have fish in outside ponds you will need to either turn down in-coming water to an absolute trickle (this dilutes the chlorine level to a safe amount for your fish) or fill up drums of water and let them sit for at least 24 hours before using (the UV of the sun evaporates chlorine).

For fish tanks or bowls inside, fill up a container of water, let it sit for at least 24 hours and then only replace 1/3 of this water at a time with what is in the tank already. If you’re still worried, you can buy de-chlorinating kits (sodium thiosulfate) at pet supply stores.

We use chlorine, not chloramine (chloramine is more toxic to fish).

Hot water cylinders

You can read more about chlorination and hot water cylinders on our website.