Drinking Water Standards

The Drinking Water Standards for New Zealand are issued by Taumata Arowai under the Water Services Act 2021.

Taumata Arowai took over responsibility for regulating drinking water from the Ministry of Health in November 2021, via the Water Services Act. They set new requirements water suppliers need to meet to provide safe water to their communities.

The standards set:

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.

Nitrates

We actively monitor nitrate levels in accordance with the Drinking Water Quality Assurance Rules.

Taumata Arowai is responsible for setting the New Zealand Drinking Water Standards which specify the maximum amount of different compounds, including Nitrates, that are safe to have in our drinking water. These are known as Maximum Allowable Values (MAVs). More information on nitrates can be found on the Taumata Arowai website.

Environment Canterbury is the regulatory authority responsible for addressing Nitrate contamination in waterways and groundwater in Canterbury. We work with Environment Canterbury and other councils on this matter. You can find a summary of the work being carried out by Environment Canterbury here.

Community & Public Health (Te Mana Ora) provides health information regarding nitrates in drinking water and links to further information at this link on the Community & Public Health website.

Interpreting Nitrate Tests Results

The amount of nitrate present in water is reported in one of two ways.

As nitrate or NO₃. The Drinking Water Standards MAV for nitrate is 50 milligrams/litre of water.
As nitrate-nitrogen or NO₃-N. The Drinking Water Standards MAV for nitrate-nitrogen is 11.3 milligrams/litre of water.

No matter which reporting approach is used, the maximum amount of nitrate acceptable in drinking water is the same.

More information regarding interpretation can be found on the Taumata Arowai website.

Sept 2024 Nitrate Test Results

Supply	Bore	Last Result Nitrate-Nitrogen (mg/L)	Range Minimum January 2023-September 2024	Range Maximum January 2023-September 2024	Drinking Water Standards MAV (mg/L)
Rangiora	Smith Street 1	0.77	0.78	0.92	11.3
	Smith Street 3	0.72	0.71	0.8	11.3
	Smith Street 5	< 0.05	< 0.05	< 0.05	11.3
Kaiapoi	Peraki Street	1.78	0.7	1.78	11.3
	Ashley Place	2.1	1.64	2.1	11.3
	Porter Place	1.81	1.71	1.89	11.3
	Davie Street	1.21	0.88	1.26	11.3
	Rugby Park	0.86	0.55	1.03	11.3
	Sewell Street	1.15	1.12	1.34	11.3
Woodend-Pegasus	EQ 1	< 0.05	< 0.05	< 0.05	11.3
	EQ 2	< 0.05	< 0.05	< 0.05	11.3
	EQ 3	< 0.05	< 0.05	< 0.05	11.3
	PW 1	< 0.05	< 0.05	< 0.05	11.3
	Gladstone Park 1	< 0.05	<0.05	0.19	11.3
	Gladstone Park 2	<0.05	<0.05	<0.05	11.3
Waikuku Beach	Kings Avenue 1	0.35	0.35	0.47	11.3
	Kings Avenue 2	0.35	0.35	0.43	11.3
	Waikuku Campground	0.17	0.13	0.41	11.3
Oxford Rural 1	McPhedrons Road	5.10	4.3	5.17	11.3
Oxford Urban-Rural 2	Domain Road 1	2.2	1.9	4.22	11.3
	Domain Road 2	2.2	1.76	2.98	11.3
Mandeville	Two Chain Road 2	2.2	2.4	4.23	11.3
West Eyreton	West Eyreton 1	2.1	1.7	2.1	11.3
	West Eyreton 3	1.85	1.64	1.85	11.3
Cust	Springbank 2	0.35	0.3	0.35	11.3
Ohoka	Ohoka Bore 2	0.42	0.35	0.44	11.3
Garrymere	Garrymere	0.55	0.25	1.17	11.3

Historic results

Chlorination / Chlorine

All public water supplies are now required by law to be treated with chlorine This is due to a decision from drinking water regulator Taumat Arowai in October.

New water regulator, Taumata Arowai took over responsibility for regulating drinking water from the Ministry of Health in November 2021, via the Water Services Act.

Under the Act all registered water supplies must submit a Drinking Water Safety Plan (DWSP) as well as introduce a residual disinfectant, such as chlorine, by 15 November 2022 - unless awarded an exemption.

Waimakariri District Council submitted six applications to Taumata Arowai seeking exemptions from having to use chlorine in our water supplies.

Government drinking water regulator Taumata Arowai has declined Waimakariri District Council’s first drinking water chlorine exemption application (for the Cust supply).

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.

The Council met with Taumata Arowai officials, including their Chief Executive, on two occasions to reiterate our programme of investment and the fact our residents want to have unchlorinated water.

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.

What's Happening with my supply?

Chlorine Testing

Council has monitoring stations that continuously monitor the levels of chlorine in the water supply network. The following graph is a representation of the data collected in a typical week for Kaiapoi, Pegasus/Woodend, and Rangiora water supplies.

Minimum and maximum levels of chlorine in the water supply network as outlined in the Drinking Water Standards:

The Water Services Regulations 2022 set out the maximum acceptable value (MAV) limit for chlorine which is 5mg/L.
Taumata Arowai (water services regulator) set out the maximum aesthetic value limit for chlorine which is 1mg/L.
Taumata Arowai set out the minimum required concentration for chlorine which is 0.2mg/L.

This graph shows that the chlorine in the water supply network is consistently within the regulated limits and is safe to consume.

Water Scheme Updates

Cust	Water has been chlorinated since November 2020 No immediate changes
Woodend-Pegasus	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
Kaiapoi	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
Rangiora	Water has been chlorinated since 14 November 2023
Waikuku Beach	Water has been chlorinated since 7 November 2023
Oxford Urban	Water has been chlorinated since 31 October 2023
Restricted supplies: Oxford Rural No 1, Oxford Rural No 2, West Eyreton, Poytzs, Summerhill, Ohoka, Fernside, Garrymere, Mandeville.	All of 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.

Click here for answers to Frequently Asked Questions about chlorine.

Last reviewed date: 02 Oct 2024

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