Annual Report on Drinking-water Quality 2011–2012

Published online: 
20 June 2013
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Summary

This report describes the microbiological and chemical quality of water in New Zealand drinking-water supplies serving populations of more than 100 people, and progress towards meeting the requirements of the Health Act 1956, from July 2011 to June 2012.

The report comprises the level of compliance for each category of water supplier (large, medium, minor, and small) with sections 69S to 69ZC of the Health Act 1956, and the drinking-water standards.


Frequently Asked Questions


Is my drinking-water safe?

During the reporting period over 2.9 million New Zealanders on reticulated supplies serving over 100 people were provided with drinking-water that met all the Drinking-water Standards and, therefore, was demonstrably safe. 

In the early 1990s, the Ministry of Health set a target of 95 percent compliance with bacterial and chemical standards by drinking-water supplies serving over 500 people. In this reporting period bacterial compliance was achieved for 95.8 percent of the population and chemical compliance for 95.7 percent of the population (on all supplies serving over 100 people). There is also an ongoing improvement in protozoal compliance which reached 79.8 percent of the population in this reporting period.

For those people on supplies that had E.coli or chemical levels above the maximum acceptable values, remedial actions were taken immediately in almost all cases, and there were no reports of water-borne illness outbreaks among these communities. Water supplies that did not comply due to inadequate monitoring (a technical non-compliance) were not necessarily unsafe, but monitoring is important to be sure water is safe. Likewise, for those supplies that have not met protozoal compliance because adequate barriers are not yet in place to ensure the drinking-water is free of protozoa, the risk is also not known.

Public health risk management plans are developed and implemented by drinking-water suppliers to identify what risks may exist for a water supply and how to manage these risks – or what action to take if something does go wrong. During the reporting period 1.4 million New Zealanders were covered by a supply that was implementing a risk management plan, with a further 475,000 people on water supplies with an approved plan, ready to implement.

What is the Annual Report on Drinking-Water Quality in New Zealand 2011/12?

The report describes drinking-water quality, and progress towards meeting the requirements of the Health Act 1956 and the New Zealand Drinking-Water Standards, for all registered community drinking-water supplies that served populations of more than 100 people from July 2011 to June 2012 (covering a total of 3.8 million people).

Why is the report on the Annual Review of Drinking-Water Quality being published?

The Annual Review of Drinking-Water Quality in New Zealand 2011/12 is the latest in a series of annual reports that were first published in 1994.  Publishing the report each year fulfils a statutory requirement of the Ministry.

A number of drinking-water supplies were affected by the Christchurch earthquakes and were not included in the 2010/11 report, are they included now?

 Yes. All ten supplies that were affected by the Christchurch earthquakes have again now been included in the report. 

They were temporarily exempted from the 2010/11 report because of the impact of the earthquake. They are now all included in this reporting period (1 July 2011 to 30 June 2012). All ten supplies met the chemical and bacteriological requirements of the Standards and nine supplies meet the protozoa requirements.

The report includes information on measures other than the Standards. Why has this information been included?

The Health (Drinking Water) Amendment Act 2007 amended the Health Act 1956 and came into force in 2008. It included a number of duties for water suppliers, including taking all practicable steps to comply with the drinking-water standards.  

The Act requires information on water-suppliers compliance with their duties to be included in the report.

What steps are being taken to raise overall compliance with the drinking-water standards?

The government is committed to ensuring that all New Zealanders have access to safe drinking-water. Failure to maintain high microbiological standards by not managing bacteria and protozoa leads to the potential for outbreaks of disease. 

The following initiatives have been established or developed and are being implemented to ensure New Zealand’s drinking-water remains safe:

  • drinking-water subsidies to assist small, disadvantaged communities to have access to safe drinking-water – see Applying for a Drinking-water Subsidy: Guidelines for applicants and district health board public health units
  • external surveillance of drinking-water supplies by drinking-water assessors and health protection officers from local DHB public health units
  • publication of a Register of Community Drinking-Water Suppliers
  • publication of a Register of Ministry of Health Recognised Laboratories for drinking-water compliance tests
  • maintenance of a national drinking-water quality information database
  • publication of Guidelines for Drinking-Water Quality Management in New Zealand
  • publication of Drinking-water Standards for New Zealand (since 1984)
  • water suppliers are progressively required to prepare Public Health Risk Management Plans and to take “all practicable steps” to comply with the drinking-water standards.

How does compliance with the drinking-water standards compare with last year?

During the reporting period over 2.9 million New Zealanders on reticulated supplies serving over 100 people were provided with drinking-water that met all the Drinking-water Standards. 

While compliance with all drinking-water standards decreased by 1.8 percent to 76.7 percent in population terms during 2011/12, bacterial compliance was 95.8 percent and chemical compliance was 95.7 percent, and so continue to exceed the Ministry of Health’s targets. 

The drinking-water standards, based on the World Health Organization guidelines for drinking-water quality, give highest priority to health risks arising from microbial contaminants because they can lead to rapid and major outbreaks of illness. There is also an ongoing improvement in protozoal compliance which reached 79.8 percent of the population in this reporting period.

What has caused the small drop in overall compliance?

For a water supply to be fully compliant it must have met the drinking-water standards for chemicals, bacteria and protozoa. We know that 18 zones (covering 143,000 people) which complied in the 2010/11 period did not comply this reporting period. This was offset slightly by 24 zones (serving 71,000 people) who have achieved overall compliance for this reporting period but previously didn’t (in 2010/11). Ministry of Health officials and ESR scientists looked closely at the small drop in overall compliance to see if there are any clear reasons.

The most common reason identified was a fall-off in the frequency of monitoring, mainly due to suppliers not meeting all the requirements of the sampling schedules for their supply, especially over holiday periods, rather than due to any cost-cutting measures. 

Only a few of the non-compliances were because the water had levels of contaminants above the drinking-water standards. In all these cases, the water suppliers took remedial action and there were no outbreaks of disease reported.

Of the people in non-compliant zones, how many are due to poor monitoring rather than poor water?

Over 40 percent of the population on all the supplies, which failed the bacteriological standard in this reporting period, did so because of insufficient monitoring. 

Looking at all the non-compliant supplies that had been compliant in the previous year, around 18 percent of the population on these supplies (25,859 people) failed because of inadequate bacteriological monitoring. Monitoring is important for determining whether supplies meet appropriate standards.

How many of the non-compliant supplies will be covered by planned subsidy improvements underway or soon to be underway?

Of the 4.2 percent of the population that received water that did not comply bacteriologically 20.7 percent (32,853 people - 35 zones) are in the process of upgrading their supplies:

  • 20,188  people are covered by supplies currently awaiting start of works/works underway;
  • 5,821 people are covered by supplies who have completed works since the end of the survey year;
  • 3 zones serving a total of 2,884 people completed works late in the survey;
  • 1 zone of 360  people completed early 2012 (technical/monitoring non-compliance); and
  • 3 zones serving a total of 3,600 people completed early in the survey period (all technical/monitoring non-compliance)

Publishing information

  • Date of publication:
    20 June 2013
  • ISSN:
    1179-2604 (Online)
  • HP number:
    5596
  • Citation:
    Ministry of Health. 2013. Annual Report on Drinking-water Quality 2011–2012 Wellington: Ministry of Health.
  • Ordering information:
    Only soft copy available to download
  • Copyright status:
    Owned by the Ministry of Health and licensed for reuse under a Creative Commons Attribution 4.0 International Licence.
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