Drinking Water for New Zealand

Managed by ESR for the Ministry of Health.         Data extracted from the National DWO Database.

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Supply Compliance with the Standards Explained

Use this page to understand the compliance details as listed against a particular supply. For a more general explanation of compliance with the Drinking-Water Standards, see the compliance monitoring page. For more on the structure of a supply, see the explain register entry page.

Compliance with What?

Drinking-water supplies in New Zealand are expected to demonstrate compliance with the New Zealand Drinking-Water Standards 2005. These specify water monitoring (ie taking samples for testing) and other requirements for supplies, both at the treatment plant and within the distribution zone itself. Supplies may continue to use the 2000 Standards instead, up until the end of 2014, as long as they have received prermission to do so from the Ministry of Health..

The number of samples to be tested varies depending upon the size of the community, the quality of source water being used (eg deep groundwater versus river or lake water), and the treatments and risk-minimising processes that are in place.

Compliance with the Standards is measured by looking at how the zone or plant meets the requirements for a 12 month period (measured between 1 July and 30 June). Data on this website is from the Annual Report for the latest such period for which data has been publicly released.

The Ministry of Health website has the full report for this year shown on this site, which you can download as a pdf file. Check our Official Documents page for this and earlier years.

Which Supplies are Reported?

The Health Act, as revised for drinking-water in 2007, allocates each drinking-water to a category and a population size band.

Supply Category

A water supply can be categorised in a number of ways, according to the suppliers relationship with the population supplied. Categories include:

Supply Size

Water supplies are classified according to the population served, as follows:

Currently the Annual Report includes only "network" supplies with distribution zones supplying more than 100 people. In other words, neigbourhood supplies are not reported, and nor are any self-supplies or specified self-supplies. When the compliance information is presented, such zones will say "Reporting not required."

Why do some zones report compliance as "No data available"?

This typically means that the zone is a new one, either as part of a new subdivision or, more likely, because the local council has reorganised their supply structure. In that case, there is not a full year's data available to evaluate compliance.

Note that, if a supply was required to be evaluated for compliance but did not provide information to the drinking water assessors, then it would be reported as non-complying rather than as having "no data available."

Compliance Requirements

Supplies are required to meet a number of provisions detailed in the Health Act, some of which are progressively required from a year that depends upon the supply size. For example, large supplies needed to meet those provisions from 1 July 2012. Details of legislative compliance are included in the Annual Report but are not currently included on this website, other than the status of a supply's Water Safety Plan.

How to Read a Compliance Page

The short answer: Read the colour code. Green is good, red is bad, and other colours are somewhat in-between.
For the full story, read on ...

Compliance is reported at the zone level

While both the zone and any contributing plants are normally monitored, the Annual Report and this site describe results in terms of the zone. This is logical because the zones are where the water is used.

What is Reported?

Compliance line Description
Standards Used For zones in the report, options are DWSNZ 2005, DWSNZ 2000, 'Compliance not attempted', 'No data' and 'Reporting not required.'
Bacteria achieved

Normally Yes or No, and refers to monitoring for E. coli in the zone.

Entries such as "From Aug 2014" indicate that the zone meets compliance requirements from this month onwards. This option aims to encourage previous non-compliers to commence monitoring at the earliest opportunity, and to be recognised for that. The option cannot be used where monitoring was ongoing all year but the supply only complied since a more recent month.

Protozoa achieved Yes or No. Refers to all contributing plants. ie If multiple plants contributie water to the zone, and one fails, then this is No.
Chemical achieved

Yes or No. Refers to all Priority 2 determinands for the zone and its contributing plants. If one P2 fails, then this is No.

If there are no P2 determinands, then a 'Chemical achieved' line is not shown.

If P2 determinands, then these are then listed by their short names and with individual status. See the Priority 2 determinands page for full names of determinands. Status is marked as follows:

_ok = achieved Standard

_x    = failed Standard

_xT = failed Standard and has excessive transgressions.

If multiple contributing plants have the same P2 determinand, eg Fluoride, then the worst case is used.


Compliance at the Treatment Plant

As explained above, treatment plant compliance is not separately reported on the website except as it is incorporated in the zone compliance. This reflects the approach used in the Annual Report.


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