The Drinking Water Quality Assurance Rules for New Zealand are issued by Taumata  Arowai under the Water Services Act 2021 and set out the requirements water suppliers need to meet to provide safe water to their communities. The standards set out:

• Maximum amounts of substances, organisms, contaminants and residues allowed in drinking water.
• Criteria for demonstrating compliance with standards.
• Action to be taken in the event of non-compliance with standards.

Chlorine is used as a preventative measure against contamination because it kills the bacteria that can get into water supplies and spread disease, helping ensure supplies are safe to drink.

The new Water Services Act 2021 came into effect on 15 November 2021 requiring all Councils in New Zealand to be able to provide residual disinfection (chlorine) for all public drinking water supplies.

This is to keep drinking water safe.

All water on Westland District supplies is treated at water treatment plants before it enters the pipes to your property. Chlorination provides an additional safe, effective treatment through the pipes, all the way up to your tap.

Chlorination has been used safely and effectively all over the world for around 120 years as a preventative treatment to avoid contamination of water supplies. It keeps millions of people all round the world safe from waterborne disease, including the majority of New Zealanders.

For supplies that are not already chlorinated, the Council is working through the process one supply at a time and we will contact you before the chlorine is turned on for your supply. To receive a reminder when the chlorination is turned on for your supply please sign up to our text message service.

If you are on a supply that is already permanently chlorinated, then nothing will change for you.

Chlorine has been used safely all over the world for around 120 years. It keeps millions of people all round the world safe from waterborne disease.

The majority of New Zealand’s drinking water is chlorinated providing effective treatment to keep the water safe for those communities.

The amount of chlorine added to the water supply is carefully managed to ensure levels of chlorine in the water people drink are absolutely minimised.

Chlorine levels are monitored continuously at our treatment plants to ensure the levels are safe. Monitoring equipment is also being added throughout the networks over time.

The new rules require that we have a minimum dosage of 0.2 parts per million (ppm) in the water when it reaches each property on the supply.

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

In the early stages of chlorination you might notice a slight change in taste as the new treated water moves through the scheme and mixes with unchlorinated water in the Council’s reservoirs. However, most users report that this settles after the first few days.

At the minimum dose most people should not be able to smell or taste chlorine. However, the smell and taste of chlorine increases when the chlorine is consuming any organics, or when the dose is increased. So being able to smell or taste the chlorine could mean that it is doing its job of treating anything that could make your drinking water unsafe. 

You can install an under-bench filter or fill a jug of water and leave it on the bench or in your fridge overnight. The chlorine 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 supplies stores and water filter companies.

The use of filters will reduce any risks for those on dialysis. This can be arranged through Te Whatu Ora Waitaha Canterbury’s Nephrology Department.

What to do if you don’t want to shower or wash your clothes in chlorinated water

You can buy at your own cost a filter that attaches to your water supply where it enters your property. It will remove all the chlorine from the water to your home.

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. If you notice increased skin irritation, asthma symptoms or other symptoms, seek medical advice from your GP.

In Westland you can  contact Healthline any time for free health advice on 0800 611 116.

What to do if you don’t want to shower or wash your clothes in chlorinated water

You can buy at your own cost a filter that attaches to your water supply where it enters your property. It will remove all the chlorine from the water to your home.

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 and let it sit for at least 24 hours and then only replace a third of the water at a time. If you’re still worried, you can buy de-chlorinating kits (sodium thiosulfate) at pet supplies stores.

There are multiple factors that can lead to a hot water cylinder leaking, and then needing to be replaced. These include: the chemical composition of the water, the age of the cylinder, the type of cylinder, whether there is any debris in the cylinder, and the quality and thickness of the copper used.

Because of this, the Council will not be compensating property owners where cylinders fail.

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

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

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.

Public consultation on the Water Services Act 2021 was run by the Parliamentary Health Select Committee in March 2021 as part of the Parliamentary process for the passage of the bill.