Annual Report On

Annual Report on

Drinking-water Quality

2010–2011

Citation: Ministry of Health. 2012.

Annual Report on Drinking-water Quality 2010–2011.
Wellington: Ministry of Health.

Published by the Ministry of Health in June 2012

PO Box 5013, Wellington, New Zealand

ISSN 1176-1424 (Print)

ISSN 1179-2604 (Online)

HP 5444

This document is available at

Ministry of Health Disclaimer

The data and analyses contained in the Annual Report on Drinking-water Quality 2010–2011 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.

All local authorities, bulk water suppliers and relevant government agencies were given the opportunity to comment on and check this document for accuracy prior to publication.

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.

Annual Report on Drinking-water Quality 2010–2011

1

Contents

Key findings...... 1

Introduction...... 3

Methods...... 4

Findings...... 6

Large water supplies (more than 10,000 people)...... 7

Medium water supplies (5001 to 10,000 people)...... 8

Minor water supplies (501 to 5000 people)...... 10

Small water supplies (101 to 500 people)...... 11

Earthquake-related drinking-water monitoring in Christchurch...... 13

Interpretation and discussion...... 16

Key to symbols and abbreviations...... 25

APPENDIX 1. Compliancesummary...... 26

APPENDIX 2A. Microbiological compliance...... 39

APPENDIX 2B. Chemical compliance...... 53

APPENDIX 2C. Requirements of the Health Act 1956...... 78

APPENDIX 3. Christchurch Earthquake Report...... 99

Annual Report on Drinking-water Quality 2010–20111ii

Key findings

This report describes drinking-water quality for all registered community drinking-water supplies that served populations of more than 100 people from 1 July 2010 to 30 June 2011, except for 10 supplies that were affected by the Christchurch earthquakes and were exempt from the annual survey.It describes how registered community drinking-water 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.

Approximately 97 percent of New Zealanders (3,309,000 people) on registered community drinking-water supplies serving more than 100 people received bacteriologically-compliant drinking-water (compared with 96 percent reported in the 2009–2010 reporting period). Protozoal compliance was achieved for 79 percent of the population (compared with 78percent in the 2009–2010 reporting period), and 97 percent of the population on registered community drinking-water supplies that served populations of more than 100 peoplereceived chemically-compliant water (compared with 96 percent in the 2009–2010 reporting period).

Overall, 78 percent of New Zealanders (2,670,000 people) on registered community drinking-water supplies serving more than 100 people received drinking-water that met all of the requirements of the Standards in the 2010–2011 reporting period. Overall compliance with the Standards has increased by 2 percent in population terms in the 2010–2011 reporting period, compared with the 2009–2010 reporting period. As was expected, compliance with the Standards was generally highest in the large supplies and lowest in the small supplies. The exception to this was that small supplies showed the greatest chemical compliance, because they are not required to be assessed for chemical contamination, so they comply by default.

The provisions of the Health Act 1956 take effect progressively over the next few years, starting on 1 July 2012 for large supplies. As part of these provisions,water suppliers will be required to prepare public health risk management plans.Overall,distribution zones serving 27percent of the population (32 percent of zones) had implemented their public health risk management plans by the end of the reporting period.Zones serving a further 69 percent of the population (44 percent of zones) were preparing their plans.All of the large drinking-water suppliers had either implemented their plans or they were atvarious stages of plan preparation.The rate of development and implementation decreased as population size decreased.Thirty-fourpercent of the smaller suppliers had not started preparing their public health risk management plans, but smaller suppliers have longer to comply with the provisions of the Health Act 1956.

During the 2010–2011 reporting period, a number of other actionswere carried out by water suppliers. These are described below.

• Monitoring: Overall,distribution zones serving 97percent of the population (85percent of zones)met the monitoring requirements of the Standards. All large- and medium-sized supplies, serving a total of 2,863,000 people, met theE. colimonitoring requirements, with small supplies monitoring the least.
• Adequacy of supply: Overall, distribution zones serving 83 percent of the population (91 percent of zones)met the requirement for adequacy of supply during the reporting period, with 72percentof large supplies and 95 percent of small supplies meeting the adequacy of supply requirement.This may be due,in part,to information being received from only 54 of 69 large supplies.However, even if expressed as a percentage of the supplies from which information was received, the percentage of large supplies meeting the requirement (93 percent) is less than the reported rate of 98 percent for all small supplies that provided information.
• Source protection: Overall, distribution zones serving 86 percent of the population (88percent of zones) met this requirement. Source protection generally increased as the size of the zone population decreased. If only supplies that responded to the survey are included, the rates in terms of zones are 96 percent, 100 percent, 97percent and 94percent for large, medium, minor and small classes of supply, respectively.This may be due to the low response rate by large supplies to this survey, which are counted as not meeting this requirement.
• Records: Adequate records were maintained fordistribution zones supplying
  99.5percent of the population(94percent of zones).
• Complaints: Overall, distribution zones serving 99.7percent of the population (97percent of zones)investigated complaints.
• Remedial action: Almost all supplies undertook remedial action in response to transgressions.Zones serving2 percentof the population (4percent of distribution zones) did not take remedial action when necessary.

By the end of the 2010–2011 reporting period, all size categories of drinking-water supplyhad reported good progress towards meeting the legislative requirements of the Health Act 1956.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 requirementsthan smaller categories of supplies.

While drinking-water suppliers are not yet expected to meet the requirementsof sections 69S to 69ZC of the Health Act 1956, including the requirements regarding monitoring, adequacy of supply, source protection and public health risk management plans, most drinking-water supplies met these requirements.Overall, water suppliers are meeting their current requirements and many are meeting their future requirements.There is a tendency for fewer smaller supplies to have met their current requirements under the Health Act 1956than the larger supplies.Many supplies already meet the requirements of the aspects of the Health Act 1956 that are being phased in, and many others are making progress towards meeting these requirements.

Christchurch water supplies

Christchurch was struck by earthquakes of magnitude 6.3 or greater that damaged the drinking-water infrastructure on three occasions during the 2010–2011 survey period.Although someEscherichiacolitransgressions occurredfollowing the earthquakes, the council’s actions controlled the elevated risks caused by earthquake damage and minimised the health risk posed bythe drinking-water.The best measure that we have of the success of the public health response is the lack of a recorded increase in potentially waterborne diseases in the periods following the earthquakes. Christchurch City Council, Civil Defence and Emergency Management and the public health services are commended for their responses to the extreme risks that the earthquakes presented to the drinking-water supply infrastructure.

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 2010 to 30 June 2011, except for 10 supplies that were affected by the Christchurch earthquakes and were exempt from the annual survey.It describeshow 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 Health Act 1956[2].

In addition, the report meets the requirement of the Health Act 1956for the Director-General to prepare and publish a report on drinking-water each year that includes information about the quality of drinking-water and compliance of drinking-water suppliers with the Standards and the Health Act 1956.

In 2009, the requirement for each categoryof water supplier to comply with sections 69S to 69ZC of the Health Act 1956 (relating to drinking-water) was deferred for three years.These requirementswill come into force on staggered dates beginning on 1 July 2012 and proceeding as follows:

• 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 Council Community 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. Thereport then presents the findings regarding compliance with the Standards and meeting the legislative requirements of the Health Act 1956 for each of the four size categories of the drinking-water supplies,and describestheearthquake-related drinking-water monitoring in Christchurch. This is followed by a discussion and an interpretation of the findings.

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 distribution, that is, the quality of water supplied to consumers.

Two surveys were used to gather information from registered community drinking-water supplies that served populations of more than 100 peoplefrom 1 July 2010 to 30 June 2011.The first survey sought information about themicrobiological and chemical quality of the drinking-water, water treatment processes in use, the means used to demonstrate compliance with the Standards, as well as the status of public health risk management plans.This survey utilised the online Water Information New Zealand (WINZ) database.

The second survey was new for the 2010–2011 reporting period and sought information relating to the management of drinking-water supplies by drinking-water suppliers in terms of the requirements of the Health Act 1956 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 supplies that served more than 100 people, based on the information contained in the Register of Community Drinking-water Supplies as at 30 June 2011, except for 10 supplies that were affected by the Christchurch earthquakes and were granted an exemption from the annual survey

• the population figures used in this report have been taken from the distribution zone populations as recorded in WINZ.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

• 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’compliance statistics, supplies that achieved compliance part way through the survey period as a result of improving treatment processes or monitoring programmes, have been marked as compliant for that aspect.These supplies can be identified in Appendix 2A

• 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 compliance is assessed at the treatment plant and not at the distribution zone.However, because the unit of analysis for this report is the distribution zone, it was necessary to allocate protozoal compliance to each distribution zone.A zone was determined to be compliant with the Standards if all of the treatment plants supplying the zone were protozoal-compliant.A few treatment plants were unused during the survey period – these were omitted from the report

• a small number of drinking-water suppliers did not respond to thesurveys.These zones that did not provide data have been marked as non-compliant for the purposes of this report

• the acceptable answers to the questions about the legislative requirements included “not applicable” (N/A).The percentage of supplies meeting the requirements of the legislation was calculated as the percentage of zones that answered “yes” or “N/A”

• the percentage figures used for compliance with the Standards and meeting the requirements of the Health Act 1956 were calculated using the number of zones or populations in the zones reported in the WINZ survey

• all percentage figures in this report are rounded. Accordingly, totals may not add up to 100percent.

Data quality assurance was built into all stages of the process, from data collection to reporting. A number of checks, including peer reviewing and duplicate analysis, were employed to ensure the reported data 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 survey assessing compliance with the Standards than for the survey assessingcompliance with the requirements of the Health Act 1956, due to ESR’s greater familiarity with the WINZ survey module and the comprehensive data collection approach utilised in the module.

Findings

This report covers the 653registered community drinking-water supply zones that served populations of more than 100 peoplein the 2010–2011 reporting period, andcovers a total population of3,401,403people.

The report does not include the drinking-water supplies affected by the three major earthquakes that occurred in Christchurch during the reporting period.There were 10 zones affected, serving 400,020 people.Earthquake-related drinking-water monitoring in Christchurch is described at the end of this section.

Table 1 summarises compliance with the Standards for the 2010–2011 reporting period. Table 2 summarises the status of public health risk management plans, according to the size of the zone, and Table 3 summarises to what extent supplies met legislative requirements of the Health Act 1956. Detailed results of drinking-water qualitymonitoring and compliance for individual water supplies are shown in Appendices 1 and 2.

Table 1: Compliance with the Standards for the 2010–2011 reporting period

Size of supply
Large
(over 10,000 people) / Medium
(5001–10,000people) / Minor
(501–5000people) / Small
(101–500people) / Total
No. of zones / 69 / 36 / 243 / 305 / 653
Registered Population / 2,601,040 / 262,005 / 457,499 / 80,859 / 3,401,403
No. of complying zones (% of complying zones within band)
Bacteriological
compliance / Zones / 69 (100%) / 34 (94.4%) / 212 (87.2%) / 211 (69.2%) / 526 (80.6%)
Population / 2,601,040 / 243,305 / 406,284 / 58,589 / 3,309,218 (97%)
Protozoal
compliance / Zones / 57 (82.6%) / 17 (47.2%) / 73 (30%) / 52 (17%) / 199 (30.5%)
Population / 2,376,175 / 127,978 / 170,732 / 15,609 / 2,690,494 (79%)
Chemical
compliance / Zones / 66 (95.7%) / 33 (91.7%) / 218 (89.7%) / 303 (99.3%) / 620 (95%)
Population / 2,558,415 / 244,509 / 419,617 / 79,968 / 3,302,509 (97%)
Overall compliance / Zones / 57 (83%) / 16 (44%) / 67 (28%) / 46 (15%) / 186 (28%)
Population / 2,376,175 / 118,443 / 161,191 / 13,840 / 2,669,649 (78%)

As the transition from the 2000 Standards to the 2005 Standards is scheduled to take several years and drinking-water suppliers may elect which of these Standards they operate under, compliance is assessed against the Standard the supplier has chosen to comply with.Of the 653 registered community drinking-water supply zones serving more than 100 people, 196and 436 zones chose the 2000 Standards and the 2005 Standards, respectively, and the remaining 21 zones did not apply the Standards.Where information was not received, these supplies were deemed to be non-compliant with the Standards.