Drinking Water
Drinking Water Assessment Unit, Auckland (DWAU)
The availability of safe drinking-water for all New Zealanders is a fundamental requirement for public health. To achieve a high standard of drinking-water quality and management in New Zealand the DWAU works to promote the understanding and application of the principles of public health safety by water suppliers and the general public.
The DWAU serves as a regulatory body that grades water supplies, maintains a monitoring and surveillance system (WINZ), provides advice and information on drinking water supplies, investigates public health problems arising from drinking water, prepares contingency plans for emergency response, promotes public knowledge on drinking water quality, and verifies where appropriate Public Health Risk Management Plans for Drinking Water. These programmes are designed to optimise the safety and quality of all drinking water available for public consumption in the Auckland Region (See specific programmes below).
DWAU Description
The DWAU has been established for assessment of the performance of drinking water suppliers, with respect to compliance with the Health Act 1956 and subsequent amendments, and the Drinking Water Standards for New Zealand.
Drinking Water Assessors (DWAs) are accredited to function in accordance with ISO / IEC 17020. All DWAs either within the Unit or as may be subcontracted by the Unit are qualified and experienced Health Protection Officers, who also hold the Diploma in Drinking Water Assessment.
The Register of Community Drinking-Water Supplies
The Register of Community Drinking-Water Supplies (the Register) lists over 2000 community drinking-water supplies in New Zealand. For each supply, the source of water, the plants where water is treated and the distribution zones are listed, together with any public health gradings (for supplies serving more than 500 people) that have been given and contaminants of public health concern (Priority 2 determinants) known to be present. The Register 2006 is available in all public libraries or from the Ministry of Health web site.
Drinking Water Standards for New Zealand
The Drinking Water Standards for New Zealand (DWSNZ) set the criteria for assessing the quality and safety of community drinking water supplies. The standards prescribe Maximum Acceptable Values (MAVs) for determinants of public health significance and provide a yardstick against which drinking-water quality is measured. They also specify monitoring requirements, laboratory competence and remedial measures to be taken in the event of the standards being breached.
Plumboslovency Fact Sheet
Guidelines for Drinking Water Management
The Guidelines for Drinking-Water Quality Management in New Zealand (the Guidelines) provide more detailed information on the public health management of drinking-water and the properties of drinking-water determinants of public health aspects of drinking-water to water supply personnel, health personnel and the general public.
Copies are available in all public libraries or from the Ministry of Health website.
Public Health Risk Management Plans (PHRMPs)
Prior to 2001, public health management of supplies relied largely on monitoring the quality of the water produced by individual water suppliers to check that it complied with the DWSNZ. While monitoring is always important, PHRMPs for drinking-water supplies provide the additional benefit of reducing the likelihood of contaminants entering supplies in the first place. Also, by the time monitoring shows that contaminants are present, something has already gone wrong and a hazard is already present in the water. PHRMPs encourage the use of risk-management principles during treatment and distribution so that monitoring is not the only water quality management technique used thereby further reducing the risk of contamination.
The Ministry of Health makes PHRMP guides available on its website.
For small water suppliers (< 500 populations) please also see Drinking Water Assistance Programme (DWAP) below.
Grading
The purpose of the public health grading of community drinking-water supplies is to provide a public statement of the extent to which a community drinking-water supply achieves and can ensure a consistently safe and wholesome product. This is determined by the extent to which a community drinking-water supply conforms to the DWSNZ and whether adequate barriers to potential contamination are in place to minimise risk to public health. The DWSNZ sets out the minimum requirements for safe drinking-water, while the grading (and the PHRMPs) provide further assurance that safe drinking-water can be achieved consistently. The grade for supplies serving over 500 people can be found on The Register of Community Drinking-Water Supplies. Grading explanatory notes and grading forms can be found online.
Annual Review of Drinking-Water Quality in New Zealand
The Annual Review of Drinking-Water Quality in New Zealand provides a public statement of the extent to which a community water supply complies with the requirements of the current Drinking-Water Standards for New Zealand. The Annual Report complements the public health grading of drinking-water supplies by providing an annual statement of whether an individual drinking-water supply complies with the chemical and microbiological quality requirements of the DWSNZ. This information is more up to date than that provided by the grading. The Ministry of Health has more information on the Annual Review on its website.
Surveillance Programme
Surveillance is carried out by Health Protection Officers (HPOs) as part of the audit of the supplier’s compliance with the DWSNZ. The surveillance programme may require some confirmatory sampling by HPOs and does not preclude health authorities from carrying out demand-driven sampling to investigate suspected pollution events and disease outbreaks.
Drinking Water Assistance Programme (DWAP)
The Ministry has set up a Drinking Water Assistance Programme (DWAP) which offers advice to small water suppliers on the operation, management and upgrading of their water supplies and will provide assistance to help them write their Public Health Risk Management Plans. If this programme shows that capital development is needed, small water suppliers can then apply for a share of $150 million available over the next ten years. Small water suppliers including those owned by local councils, servicing a population of up to 5,000 are eligible to apply for funding.
For further information on the DWAP please contact the TAPs Facilitator at the Drinking Water Assessment Unit on (09) 623 4600.
