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Proposed National Environmental Standard for Human Drinking-water Sources

Acknowledgements

1 Summary

2 Introduction

3 Why Do We Need a National Environmental Standard for Source Water

4 The Proposed Standard

5 Supporting Information

6 Costs and Benefits

7 What Next?

Appendix 1: Definitions

Appendix 2: Types of Activities that Pose a Threat to Source Water Quality

References

3 Why Do We Need a National Environmental Standard for Source Water

3.1 Managing drinking-water from source to tap

Most of the New Zealand population receives safe drinking-water. Comparisons show New Zealand has some of the best drinking-water quality in the world, mainly as a result of the comparative lack of industry. [In recent studies of drinking-water supplies, only 4 percent of the population was shown to be receiving water that was contaminated. However, 22 percent received water that had not been shown to be safe, ie, not monitored or not monitored sufficiently (Taylor and Ball, 2004).] However, New Zealand does have potential issues with nutrient and microbiological contamination of water, caused in part by our large primary industry base. Risks from microbiological contamination of water by, bacteria, protozoa and viruses are of most interest.

There is currently no specific requirement in the RMA for consent authorities to consider the impact that proposed activities may have on source water in a drinking-water supply catchment. Consequently, there is potential for land use activities or discharges to be consented that reduce water quality at the point of abstraction to below that which the plant is designed to treat. This presents potential health risks to the community and may result in significant costs to the supplier in upgrading treatment facilities.

Part 7 (section 126) of the Local Government Act 2002 requires local authorities to undertake a specific assessment of the quality and adequacy of drinking-water supplies. However, there is no mandated requirement to manage source water quality, which is the aim of this standard.

There is potential for unauthorised discharges (often accidental and unpredictable) to contaminate water supplies. For example, a breach of a discharge consent condition might threaten the water supply. Our proposal will ensure water suppliers are notified of such incidents.

Modern management requires a "multi-barrier" approach to drinking-water supply to minimise the potential for waterborne disease outbreaks in New Zealand. [The Ministry of Health is proposing amendments to the Health Act 1956 to implement an integrated system of procedures, processes and tools that collectively prevent or reduce the contamination of drinking-water from source to tap, with the aim of reducing risks to public health (Taylor, 2004).] This means that if one barrier fails, others will be in place (see Figure 2, Legislative boundaries).

The Ministry for the Environment is proposing a national environmental standard under the RMA to improve how drinking-water is managed at source. This standard will complement Ministry of Health legislation and standards for improving drinking-water supply and delivery, and ensure a comprehensive approach to managing drinking-water from source to tap.

3.2 How New Zealand manages risks to drinking-water supplies

Overseas outbreaks of infectious disease have resulted from a combination of land use and treatment plant failure. These risks are similar for water supplies in New Zealand. Table 1 shows the legislation that seeks to avoid or mitigate the risk to catchment threats to drinking-water supplies.

Table 1: Statutory controls that manage risks

3.3 Ensure that the impact a proposal has on community drinking-water supplies is assessed in resource consent applications

While section 5 of the RMA refers to social, economic and cultural wellbeing for people and communities, there is no specificrequirement for consent applicants to consider the impact of their proposed activity on community drinking-water supplies. Whilst it can be argued that the definition of environment in the RMA includes public health, there is no specific reference to community drinking-water supplies in the Act. Water suppliers consider that RMA decision makers often struggle to balance concerns with a proposed activity's impacts on a water supply against ecosystems impacts.

This can be critical for human drinking-water management. Two significant examples of drinking-water supply contamination, Walkerton and Milwaukee, [In 1993, the city of Milwaukee was affected by a Cryptosporidium outbreak, infecting 403,000 people. In May 2000, an outbreak of E. coli 0157 affected the small rural town of Walkerton, Ontario, infecting 2000, killing seven, with a further 27 requiring kidney dialysis for the rest of their lives.] were a consequence of land use activities. There needs to be a mechanism in place to ensure that water supplies in New Zealand are adequately protected. Our proposal will be specific about protection of drinking-water sources.

3.4 Increase shared understanding between water suppliers, local authorities, resource users and interested parties

Roles and responsibilities of councils involved in the management of drinking-water sources are generally well defined. Local authorities control and regulate activities in drinking-water catchments, and water suppliers (usually territorial local authorities, private industry or small communities) [Greater Wellington (Wellington Regional Council) is a water supplier, as well as a catchment manager.] ensure abstracted water is delivered to the consumer in a potable form.

These separate roles are covered under differing legislation, and can result in oversights. It is critical that all the differing bodies involved in drinking-water from source to tap work closely together, and understand the impact of their activities on the other parties.

The provisions for drinking-water values in regional plans are an example of the uncertainty of roles and responsibilities. For example, only six of 16 regional councils or unitary authorities have a comprehensive approach to the management of drinking-water catchments. The other councils have either not addressed the issue, or have done so in a very general way. [Ministry for the Environment, 2004.]

3.5 Ensure that permitted activity rules consider the risks to community drinking-water supplies

In New Zealand, agricultural land use is generally a permitted or unregulated activity and there may be no controls in place to manage the effects of diffuse runoff on the environment. The standard will require councils to periodically review permitted activity rules to ensure these activities will not render source water non-potable or unwholesome following treatment.

3.6 Ensure procedures are in place to protect community drinking-water supplies in the event of an unauthorised discharge

Procedures are needed to ensure water suppliers are notified of unauthorised discharges from consented activities (for example, discharges that exceed consented limits) that could adversely affect source water quality. Being advised as soon as possible will enable water suppliers to take appropriate action or advise what steps need to be taken to minimise or eliminate the risk to the supply and/or the community.

3.7 Enable councils to require appropriate action to be taken in the event of an accident or emergency

There is currently no specific requirement in the RMA for councils to notify or respond to accidents and emergencies that impact on a drinking-water supply. In most cases, council involvement will be as part of emergency planning and response. There may be situations where the scale or severity of the event necessitates cessation of abstraction in the interest of protecting the treatment plant and community health.

Table 2: Relationship between the principal Acts governing drinking-water