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12 Water Information New Zealand (WINZ)

12.1 Introduction

Water Information New Zealand (WINZ) is a national database developed by ESR for the Ministry of Health. It provides an up-to-date source of national water supply information required for drinking-water quality management, including the characteristics of supplies, public health grades, and compliance with the DWSNZ. Both permanent (location and details of the supply system) and transitory (compliance with DWSNZ and grading) data are stored in the database.

WINZ software is developed and maintained by the Water Information Systems group of ESR. The group distributes software updates to water suppliers, district health boards and other organisations that may be running WINZ. The group also maintains a website ( where some of the information contained within WINZ and other general information about water supply management can be accessed.

12.2 WINZ and its use

Three levels of WINZ have been developed to meet the specific needs of different organisations involved in the management of drinking water supplies.

12.2.1 WINZ for water suppliers

Not all water suppliers use WINZ. Those that wish to, are provided with a version of WINZ that contains information relevant to their water supply only. From the supply-specific information, the software is able to calculate the monitoring requirements and to provide a suggested sampling schedule for the supply. Once monitoring data are generated, the water supplier can store it in WINZ and the software will determine the compliance status of the supply when sufficient information is available to do this. Events such as transgressions, and the actions taken in response to them, can be recorded and stored in WINZ. Warnings of the need to take corrective actions in the event of a transgression are generated by the software.

12.2.2 WINZ for district health boards

All district health boards use a version of WINZ that is essentially the same as that provided to the water suppliers, but with some additional functions. The database provided to individual suppliers contains information about their supply only; the district health boards receive information about all supplies in their district.

For the preparation of the Review, the district health board collects compliance information from the water suppliers and uploads a summary of the information to National WINZ maintained by ESR. The collection of information from water suppliers may occur in one of three ways:

  • The water supplier uploads raw monitoring data which is processed by the district health board to assess compliance.

  • The water supplier processes its raw data to calculate compliance and uploads a summary of this to the district health board.

  • The district health board collects raw monitoring data from water suppliers who are not using WINZ and enters this information into their WINZ database.

12.2.3 National WINZ

National WINZ is maintained by ESR on behalf of the Ministry of Health. It stores high-level information, rather than sample details, uploaded from public health units as well as supply details, public health grading information. The data stored within National WINZ is used for:

  • the compilation of the Ministry of Health publications, Register of Community Drinking-water Supplies and Suppliers in New Zealand and the Review

  • analysis of water supply information to assist the Ministry of Health in policy development

  • research requiring national level information about water supplies and compliance, or information about specific water supply systems, eg, the treatment processes in use.

12.3 WINZ information relevant to NES implementation

Two types of information contained within WINZ will be relevant in implementing the National Environmental Standard. Drinking-water assessors in public health units are a useful first point of contact for obtaining and understanding information in WINZ about individual water supplies.

12.3.1 Supply details

When a water supply is registered, each component of the supply is given a unique identification code and some basic details about each supply component are stored in WINZ. For treatment plants, these details include the grid reference of the treatment plant, and the regional authority in whose territory the plant is located.

Details about treatment operations and treatment chemicals used at each treatment plant are also retained within WINZ. This information is gathered through the P2 Programme and the public health grading of supplies undertaken by the Ministry of Health through the public health units. The types of contaminants the treatment plant should be able to reduce in concentration, can be identified from knowledge of the treatment processes in use at the plant. Use of WINZ for this purpose should be as a first approximation only. A check should be made with the water supplier to confirm which processes are operational, and whether they can advise on the degree to which the treatment plant’s existing processes will reduce the concentrations of expected contaminants.

12.3.2 Compliance information

Compliance information can help to establish how well a water supply’s treatment plant is functioning, and therefore how well it will deal with the challenge of new contaminants or increased levels of existing contaminants. The Review has already been identified as a possible source of compliance information, but details about bacterial and protozoal compliance at the treatment plant in the Review are inadequate for assessing the effectiveness of the treatment plant. WINZ contains treatment plant compliance information that was not published in the Review. This information is available from the sources noted in the last paragraph of section 11.4.3.

12.4 Future developments

The next major step forward is the development of web-based WINZ. Use of this version of WINZ will require only a PC with a web browser and an internet link. No download of WINZ software will be needed.

All information presently held in National WINZ will in principle be accessible , through the website, but the areas of the database available to an individual will depend on the level of access they have been given.

The web version of WINZ is under development at the time of preparing this guide: it will take over a year to make all the information currently available through individual access WINZ (PC‑based) accessible through the web also.