Annual Report on Drinking-water Quality

2012–2013

Citation: Ministry of Health. 2014.

Annual Report on Drinking-water Quality 2012–2013.
Wellington: Ministry of Health.

Published by the Ministry of Health in February 2014

PO Box 5013, Wellington, New Zealand

ISSN 1179-2604 (online)

HP 5811

This document is available on the Ministry of Health’s website:

www.health.govt.nz

This work is licensed under the Creative Commons Attribution 4.0 International licence. In essence, you are free to: share ie, copy and redistribute the material in any medium or format; adapt ie, remix, transform and build upon the material. You must give appropriate credit, provide a link to the licence and indicate if changes were made.

Ministry of Health Disclaimer

The data and analyses contained in the Annual Report on Drinking-water Quality 2012–2013 have been supplied to the Ministry of Health by the Institute of Environmental Science and Research Limited (ESR). The Ministry of Health cannot confirm the accuracy of the data and the analyses and accepts no liability or responsibility for any acts or omissions, done or omitted in reliance, in whole or in part, on the data or the analyses.

ESR Disclaimer

This report ("the Report") is given by the Institute of Environmental Science and Research Limited (ESR) solely for the benefit of the Ministry of Health as defined in the Contract between ESR and the Ministry of Health, and is strictly subject to the conditions laid out in that Contract.

Some of the data used in this report have been received by ESR from third parties and to that extent ESR is unable to validate or verify the correctness or otherwise of that data and neither ESR nor any of its employees makes any warranty, express or implied, or assumes any liability or responsibility whatsoever for use of the report or its contents by any other person or organisation.

Contents

1.Key Findings

2.Introduction

3.Methods

4.Findings

4.1Achievement against the drinking-water Standards

4.2Compliance with the Act

4.2.1Large water supplies (more than 10,000 people)

4.2.2Medium water supplies (5001 to 10,000 people)

4.2.3Minor water supplies (501 to 5000 people)

4.2.4Small water supplies (101 to 500 people)

5.Interpretation and discussion

5.1Introduction

5.2Overall achievement against the Standards

5.3Bacteriological achievement against the Standards

5.3.1Public health significance of exceedences

5.3.2Darfield outbreak

5.4Protozoal achievement against the Standards

5.5Chemical achievement against the Standards

5.5.1Fluoride

5.5.2Other chemical determinands

5.6Status of public health risk management plans

5.7Meeting legislative requirements

5.7.1Overview

5.7.2Requirements by section of the Act

Appendix 1. Achievement Against the Standards

Appendix 2. Microbiological Achievement

Appendix 3. Chemical Achievement

Appendix 4. Requirements of the Health Act

Tables

Table 1:Achievement against the Standards from 1 July 2012 to 30 June 2013

Table 2:Achievement against the Standards between reporting years

Table 3:Bacteriological achievement against the Standards between reporting years

Table 4:Protozoal achievement against the Standards between reporting years

Table 5:Chemical achievement against the Standards between reporting years

Table 6:Public health risk management plans: all supplies status, 2012–2013

Table 7:Public health risk management plans: large supplies status, 2012–2013

Table 8:Public health risk management plans: status between reporting years

Table 9:Meeting legislative requirements: all supplies

Table 10:Meeting legislative requirements, by supply size, 1 July 2012 to 30 June 2013

Table 11:Meeting legislative requirements: status between reporting years

Annual Report on Drinking-water Quality 2012–20131

1.Key Findings

This report describes drinking-water quality for all registered community drinking-water supplies that served populations of more than 100 people (the supplies) from 1July2012 to 30 June 2013 (the reporting period), representing 3,810,000 people (the supply population).It describes how these supplies met the requirements of the Drinking-water Standards for New Zealand (the Standards) and their progress towards meeting the requirements of the Health Act 1956, as amended in 2007 (the Act).

To meet the overall requirements of the Standards, a supply must meet the bacteriological, protozoal and chemical standards. Overall, 76.9 percent of New Zealanders (2,930,000 people) on these supplies received drinking-water that met all requirements of the Standards in the reporting period.This represents a 0.2 percentage point increase in terms of supply populationcompared with the previous 1 July 2011 to 30 June 2012 reporting period.

Drinking-water achieving the bacteriological standardswas received by 96.7 percent of New Zealanders (3,684,000 people) on reported supplies during the period, compared with 95.8 percent previously, an improvement of 0.9 percentage points. However protozoal achievementdecreasedby 0.6 percentage points from 79.8 percentto 79.2 percent (3,017,000 people),andchemicalachievement decreased by 0.4 percentage points from 95.7 percentto 95.3 percent (3,631,000 people).

As expected, achievement against the Standards was generally highest in the large supplies and lowest in the small supplies.The exception to this was the rate of chemical achievement.While highest in large supplies, small supplies achieved better than medium or minor suppliesbecause they are not required to be assessed for chemical contamination and so achievedby default.

Some of the duties of drinking-water suppliers (specified in sections 69S–69ZC of the Act) take effect progressively over a number of years, having started on 1 July 2012 for large supplies.As part of these provisions, water suppliers are required to prepare and implement public health risk management plans.Overall, 45.1 percent of the supplies’ populationhave had plans implemented by 1 July 2013, while only 2.6 percent (100,000 people) are in supplies where plan drafting has not yet commenced.

Although small supplies generally do not require a public health risk management plan, these are now implemented for 37.2 percent of their supplied population.

The overall supply population with an approved or implemented plan is now 93.1 percent, up from 49.9 percent in the previous period. While this change between periods is greatest for large supplies (up 51.3 percentage points), there were improvements of 19.8 percentage points for medium supplies and 12.3 percentage points for minor supplies.

During the 1 July 2012 to 30 June 2013 reporting period, a number of other actions were carried out by water suppliers to meet the requirements of the Act.

  • Monitoring:Overall, supplies serving 95.4 percent of the population met the monitoring requirements of the Standards.Achievementagainst the Escherichia coli and chemical monitoring requirements of the Standards generally increased with the size of the supplypopulation, with 98.0 percent of large supply populations and 78.7 percent of small supply populations receiving water that met the monitoring requirements.
  • Adequacy of supply:Overall, supplies serving 98.7 percent of the population met the requirement for adequacy of supply during the reporting period, including all but one large supply, and all medium and minor supplies.
  • Source protection:Overall, supplies serving 99.7 percent of the population met this requirement, including all large and medium supplies.
  • Records:Adequate records were maintained for suppliesproviding water to99.8 percent of the population.All large and medium supplies met the records requirement.Generally, small supplies are not required by the Act to keep records, but supplies for 97.6 percent of the small supply population did so.
  • Complaints:Water suppliers investigated all of the complaints they received about the drinking-water they supplied to the population, except for eight small suppliesserving1300 people.
  • Remedial action:Almost all suppliers undertook immediate remedial action in response to transgressions.Water suppliers did not take remedial action, when necessary, in supplies serving 1.5 percent of the population.

By the end of the 1 July 2012 to 30 June 2013 reporting period, all size categories of drinking-water supply had reported good progress towards meeting the legislative requirements of the Act with the exception of monitoring and remedial actions.Water suppliers are moving towards a more proactive approach to protect health.In general, the larger suppliers have a greater level of compliance with their current requirements than smaller categories of supplies.

While all but large or new drinking-water suppliers were not required to meet sections 69S to 69ZC of the Act within the reporting period, including the requirements regarding monitoring, public health risk management plans, adequacy of supply and source protection, most drinking-water suppliers did so.

2.Introduction

This report describes drinking-water quality for all registered community drinking-water supplies that served populations of more than 100 people from 1 July 2012 to 30 June 2013 (the reporting period).It describes how drinking-water supplies met the requirements of the Drinking-water Standards for New Zealand (the Standards)[1] and their progress towards meeting the requirements of the Act.

In addition, the report meets the requirement of the Act for the Director-General to prepare and publish a report on drinking-water each year that includes information about the quality of drinking-water,achievementagainst the Standards and compliance of drinking-water suppliers with the Act.

In 2009, the requirement for each category of water supplier to comply with sections 69S to 69ZC of the Act (relating to drinking-water) was deferred for three years[2].These requirements come into force on staggered dates, beginning from 1 July 2012, as follows:

  • new and large drinking-water supplies (more than 10,000 people) from 1 July 2012
  • medium drinking-water supplies (5001 to 10,000 people) from 1 July 2013
  • minor drinking-water supplies (501 to 5000 people) from 1 July 2014
  • small drinking-water supplies (101 to 500 people) from 1 July 2015
  • neighbourhood drinking-water supplies (25 to 100 people) from 1 July 2016
  • rural agricultural drinking-water supplies from 1 July 2016 or the date on which the Standards are amended to include them, whichever is later.

The delay was to enable councils and other drinking-water suppliers to assess the impact of the current economic climate on their operations.It also enabled councils to consider the implications of the legislation on their Long Term Plans.It is the Government’s expectation that water suppliers will continue to plan for compliance.The changes did not affect the existing legal requirements for suppliers to keep records, investigate complaints and take remedial action if they became aware of contamination in their water supplies.

This report describes the methods used to gather the data and the caveats on the data and its interpretation.The report then presents the findings regarding achievement against the Standards and meeting the legislative requirements of the Act for each of the four size categories of the drinking-water supplies.This is followed by a discussion and an interpretation of the findings.

3.Methods

Information on drinking-water quality was obtained from drinking-water assessors employed by district health board public health units, using questionnaires that sought data relating to water supply quality, monitoring and management.The information was collected at the level of the distribution zone, that is, the quality of water supplied to consumers.

Two surveys were used to gather information from registered community drinking-water supply zones that served populations of more than 100 people from1 July 2012 to 30 June 2013.The first survey sought information about the microbiological and chemical quality of the drinking-water, water treatment processes in use, the means used to demonstrate achievement against the Standards, and the status of public health risk management plans.This survey utilised the online Water Information New Zealand (WINZ) database.

The second survey sought information relating to the management of drinking-water supplies by drinking-water suppliers in terms of the requirements of the Act that will eventually apply to water suppliers.An Excel spreadsheet was designed to collect the information and was completed by drinking-water assessors in discussion with water suppliers.The completed spreadsheets were returned to ESR for compilation and analysis.

The following caveats apply for the purposes of data interpretation.

  • The report includes all community drinking-water supply distribution zonesthat served more than 100 people, based on the information contained in the WINZ database as at 30 June 2013.
  • The term ‘water supply’ in this report refers to a distribution zone, which is all or part of a reticulated supply for which the water is expected to be of consistent quality throughout. While smaller communities usually have a singledistribution zone, larger communities may have two or more. Size groupings of supplies are therefore based upon the population served by each zone.
  • The population figures used in this report have been taken from the distribution zone populations as recorded in WINZ.These figures are estimates and it is not possible to determine the accuracy of the population figures.Furthermore, it is likely that the WINZ population figures include residents-only in some zones, and residents and non-residents in other zones.
  • Population figures in this report are, in general, rounded to the nearest thousand, the exception being the small water supplies section where figures are rounded to the nearest hundred.
  • It is likely that some of the community supplies are misclassified as self-supplies and vice versa.Obvious apparent discrepancies (eg, distribution zones where the name does not seem to fit the supply classification) have been queried with the drinking-water assessors, but these are not always apparent.
  • For the purposes of the Standards’ achievement statistics, supplies that met the Standards part-way through the survey period as a result of improving treatment processes or monitoring programmes, have been marked as meetingrequirements for that aspect.
  • Overall adequacy of monitoring has been assessed on the basis of Escherichia coli and chemicals.There is no requirement to monitor for protozoa in the Standards.
  • Protozoal achievement is assessed only at the treatment plant. Because this report is distribution zone-based, a zone was determined to achieve the protozoal standardsif all treatment plants supplying the zone during the survey period achieved the protozoal standards.
  • If a drinking-water supplier did not respond to the drinking-water assessors’ requests for information, then their zones would have been marked as non-compliant in this report. However, all suppliers responded for this report.
  • Acceptable answers to the questions about the legislative requirements included ‘not applicable’ (N/A) for source protection and complaints.The percentage of supplies meeting the requirements of the legislation was calculated as the percentage of zones that answered ‘yes’ or ‘N/A’.
  • Percentage figures used for achievement against the Standards and meeting the requirements of the Act were calculated using the populations in the zones as reported in the WINZ survey.
  • All percentage figures in this report are rounded.Accordingly, totals may not add up to 100 percent.

Data quality assurance was built into all stages of the process, from data collection to reporting.A number of checks, including integrity checks, peer reviewing and duplicate analysis, were employed to ensure the data reported reflected the information collected by the surveys.Additional checks of the data were made by the drinking-water assessors and water suppliers who reviewed drafts of the zone-level data reported in the appendices.

Overall, there was a higher level of quality assurance for information collected in the WINZ survey assessing achievement against the Standards than for the survey assessing achievement against the requirements of the Act.This is due to the robust design of the WINZ survey module and its associated tools, providing almost real-time data integrity checking.

4.Findings

This report covers 664 registered community drinking-water zones supplying water to 3,810,000 people in the 12-month reporting period of 1 July 2012 to 30 June 2013. Each zone served 101 people or more.

Table 1 summarises achievement against the Standards for the current reporting period.Table 2, later in the report, compares this achievement with overall results for the previous (1 July 2011 to 30 June 2012) reporting period, while Tables 3 to 5 provide similar comparisons at the bacteriological, protozoal and chemical level respectively.

The status of public health risk management plans is presented in Tables 6 to 8, while Tables9to 11 summarise the extent to which water supplies met the legislative requirements of the Act.

Detailed results of drinking-water quality monitoring,Standards’ achievement and the meeting of legislative requirements for individual water supplies are shown in Appendices 1 to 4.

4.1Achievement against the drinking-water Standards

As the transition from the 2000 Standards to the 2005 Standards (Revised 2008) is scheduled to take several years, and drinking-water suppliers may elect which of these Standards they operate under, achievement is assessed against the Standard they have chosen.Of the 664 registered community drinking-water supply zones serving more than 100 people, 482 zones chose the 2005 Standards, 163 the 2000 Standards and 19 zones used neither. In terms of population served, those receiving water assessed against the 2000 Standards have decreased to 174,000, from 225,000 people in the previous period.

Microbiological achievement is based on two main microbiological reference organisms, Escherichia coli and Cryptosporidium.Bacteriological achievement is determined primarily using Escherichia coli monitoring, whereas protozoal achievement is based on monitoring the effectiveness of the treatment processes used to remove or disinfect Cryptosporidium.

Chemical achievement was assessed for those supplies that have been identified as containing chemicals that require monitoring (known as Priority 2 (P2) determinands[3]).A water supply is assessedas achievingif it has no P2 determinands, or if it has been adequately monitored and that any P2 chemicals present are shown to be within acceptable levels.

Table 1:Achievement against the Standards from 1 July 2012 to 30 June 2013

Percentages arefor population served.

1aAchievementfor All Supplies

3,810,000 people in 664 zones.

Population / Percentage / Zones
Bacteriological achievement / 3,684,000 / 96.7% / 530
Protozoal achievement / 3,017,000 / 79.2% / 234
Chemical achievement / 3,631,000 / 95.3% / 616
Overall achievement / 2,930,000 / 76.9% / 217

1bAchievementin Large Zones