Appendix 3: Drinking water standards and assessing water services
In this Appendix, we provide further background information about the drinking water standards, and assessing water services under the Local Government Act 2002.
Drinking water standards in New Zealand
The Health (Drinking Water) Amendment Act 2007 (the Act) was passed in October 2007 and took effect from 1 July 2008. Before this legislation took effect, local authorities had more discretion in the quality of the water they supplied to their residents and communities. The Act does not require compliance with the drinking water standards, but it does require drinking water suppliers to take all practicable steps to comply. Taking steps to implement an approved public health risk management plan is considered sufficient to comply with "all practicable steps". A public health risk management plan is a quality assurance programme for providing water.
Compliance with the Act is staggered over several years, depending on the size of population served by the drinking water supply. Originally, drinking water suppliers for large communities (more than 10,000 people) were required to prepare a public health risk management plan within a year after 1 July 2008. Drinking water suppliers for smaller communities had more time to prepare a plan (see Figure 23). However, in June 2009, the Government extended these deadlines by three years, effective from 1 July 2009 (see Figure 23).
Figure 23
Deadlines for complying with the Health (Drinking Water) Amendment Act 2007
| Supply type | Population served | Original deadline | Deadline as at 1 July 2009 |
|---|---|---|---|
| New or large | More than 10,000 | 1 July 2009 | 1 July 2012 |
| Medium | 5001-10,000 | 1 July 2010 | 1 July 2013 |
| Minor | 501-5000 | 1 July 2011 | 1 July 2014 |
| Small | 101-500 | 1 July 2012 | 1 July 2015 |
| Neighbourhood | 25-100 | 1 July 2013 | 1 July 2016 |
| Rural agricultural | N/A | 1 July 2013 | 1 July 2016 |
Grading the water, treatment plants, water sources, and distribution zones
The descriptions of the drinking water standards, plant and source grades, and distribution zone grades are set out in Figure 24. (A distribution zone is a part of a town or community receiving water of a similar quality. By definition, places within a district that receive a different grade of water will be in different zones.)
Plant and source grading (A1 to U) is based primarily on the likely health risks to the community arising from bacteria, protozoa (Giardia and Cryptosporidium), and chemical substances in the source water, and how effectively the treatment plant can act as a barrier to such contaminants passing through to the reticulation system. Possible grades are A1 (best), then A to E. As well as a grade being assigned to each treatment plant, each distribution zone gets the grade of the worst treatment plant providing it with water.
Distribution zone grading (a1 to e) is based on the microbiological and chemical quality of the water, along with the condition of the reticulation system and the quality of its care. A zone grade should always be considered with the accompanying plant and source grade.
Figure 24
Descriptions of public health grades for drinking water supplies
| Grade | Description |
|---|---|
| Source/plant grade | |
| A1 | Completely satisfactory, negligible level of risk, demonstrably high quality |
| A | Completely satisfactory, extremely low level of risk |
| B | Satisfactory, very low level of risk |
| C | Marginally satisfactory, low level of microbiological risk when water leaves the plant, but may not be satisfactory chemically |
| D | Unsatisfactory level of risk |
| E | Unacceptable level of risk |
| U | Ungraded |
| Distribution zone grade | |
| A1 | Completely satisfactory, negligible level of risk, demonstrably high quality, meets Aesthetic Guidelines and has ISO 9001:2000 accreditation |
| a | Completely satisfactory, extremely low level of risk |
| b | Satisfactory, very low level of risk |
| c | Marginally satisfactory, moderately low level of risk |
| d | Unsatisfactory level of risk |
| e | Unacceptable level of risk |
Assessing water services
Section 126 of the Local Government Act 2002 sets out the requirements for assessing water services. An assessment must include (for water supply only):
- a description of the means by which drinking water is obtained by residents of, and communities within, the district, including the extent to which the water supply is provided by the territorial authority and any other person;
- an assessment of any risks to the community relating to the absence in any area of a water supply;
- an assessment of the quality and adequacy of supply of drinking water available within the district for each community;
- a statement of current and estimated future demands for water services within the district and a statement of any issues relating to the quality and adequacy of supply of drinking water for each community;
- a statement of the options available to meet the current and future demands and assessment of the suitability of each option for the district and for each community within it;
- a statement of the territorial authority's intended role in meeting the current and future demands; and
- the territorial authority's proposals for meeting the current and future demands, including proposals for any new or replacement infrastructure.