Drinking water standards and testing

The Ministry of Health is responsible for setting the New Zealand Drinking Water Standards, which specify the maximum amount of different chemical determinands that it is safe to have in our drinking water—known as Maximum Allowable Values (MAV). The current maximum allowable value for Nitrate-N is 11.3 g/m3.

We actively monitor these chemical determinands and carry out annual testing. At a minimum, Nitrate levels are tested annually, but if any results showed a level  greater than half the MAV, we increase the frequency of testing to monthly.

You can see our annual nitrate testing results for all water sources in the table below. Our 2021 results will be available in March.

We currently have five water sources (Illinois, Overbury, Dunsandel, Edendale, Darfield) that are subject to monthly testing and you can find the results in the links below.
(Please note these results are measured in mg/L. The MAV for Nitrate is 50 mg/L)

Rolleston - Illinois
Rolleston - Overbury
Dunsandel
Edendale
Darfield

In addition, Selwyn District Council monitor Nitrate level at Rolleston Water Supply reticulation.

Rolleston Reticulation Nitrate Test Results

Nitrates in our water - action being taken

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 breakdown of the work being carried out by Environment Canterbury.

Annual water sources Nitrate tests results

SourceNitrate-N (g/m3)MAVTest date

Acheron Source

<0.05

11.3

Mar-21

Arthurs Pass Source

<0.05

11.3

Mar-21

Castle Hill Source

<0.05

11.3

Mar-21

Claremont Source

1.21

11.3

Mar-21

Dalethorpe Source

0.39

11.3

Mar-21

Darfield Source - Bore 1

5.7

11.3

Mar-21

Darfield Source - Bore 2

5.1

11.3

Mar-21

Dunsandel Source

6.4

11.3

Mar-21

Edendale Source

6.1

11.3

Mar-21

Horoata Source - Glentunnel Intake

0.22

11.3

Mar-21

Malvern Hills, Hartleys Rd Source

0.38

11.3

Mar-21

Jowers Rd Source

2.4

11.3

Mar-21

Kirwee Source

5

11.3

Mar-21

Lake Coleridge Source

<0.50

11.3

Mar-21

Leeston - Gallipoli 1

0.89

11.3

Mar-21

Leeston - Lake Rd

1.15

11.3

Mar-21

Leeston - Dunsandel Rd

1.05

11.3

Mar-21

Lincoln - Eastfield Dr

1.25

11.3

Mar-21

Lincoln - Kildare Tce

1.78

11.3

Mar-21

Lincoln - West Belt

1.71

11.3

Mar-21

Lincoln - Veuve Drive

1.19

11.3

Mar-21

Prebbleton - St Patricks Well

0.58

11.3

Mar-21

Prebbleton - Shands Rd

0.46

11.3

Mar-21

Prebbleton - Well 1

0.52

11.3

Mar-21

Prebbleton - Well 3

0.63

11.3

Mar-21

Rakaia Huts Source

0.762

11.3

Mar-21

Raven Drive Source

1.34

11.3

Mar-21

Rolleston - Baltimore Well

3.5

11.3

Mar-21

Rolleston - Illinois Dr

7

11.3

Mar-21

Rolleston - Izone

3

11.3

Mar-21

Rolleston - Moore St - Well 1

1.43

11.3

Mar-21

Rolleston - Moore St - Well 2

3.6

11.3

Mar-21

Rolleston - Overbury Cres

4.6

11.3

Mar-21

Rolleston - Helpet Well 1

1.71

11.3

Mar-21

Rolleston - Helpet Well 2

2.8

11.3

Mar-21

Rolleston - Westland Place

3

11.3

Mar-21

Sheffield Source

2.8

11.3

Mar-21

Southbridge -St John St

2.9

11.3

Mar-21

Springfield Source

0.66

11.3

Mar-21

Springston Source

1.85

11.3

Mar-21

Tai Tapu Source

0.29

11.3

Mar-21

Taumutu Source

1.33

11.3

Mar-21

Te Pirita Source

4.04

11.3

Mar-21

Upper Selwyn Huts Source

0.25

11.3

Mar-21

West Melton - Elizabeth Allen

1.93

11.3

Mar-21

West Melton - Jacqueline Dr

1.44

11.3

Mar-21

West Melton - Royston Common Well

1.4

11.3

Mar-21

West Melton - Ridgeland Way

1.95

11.3

Mar-21