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Executive Summary

On-site wastewater systems provide treatment of domestic wastewater and return it to the environment within the boundaries of the property of origin. It has been estimated that in some regions at least 20 per cent of homes rely on this form of wastewater treatment. Ageing septic tanks represent the majority of on-site wastewater systems installed in New Zealand. In many areas wastewater systems are not providing adequate levels of treatment and are having an adverse impact on human health and the environment. Failing systems can:

  • create human health risks from the overflow or ponding of effluent

  • contribute to lakes, rivers, estuaries and beaches becoming unfit for swimming, gathering seafood, and marine farming

  • lead to contamination of groundwater and surface water supplies, which affects the quality of drinking-water supplies and may increase the occurrence of algal blooms.

These effects occur because of a range of factors, including poor maintenance, sensitive receiving environments (lakes, rivers, streams, etc.), high-density residential areas, shallow groundwater, and unsuitable soil types. Ongoing maintenance backed up by regular inspections can play a significant role in improving the performance of wastewater systems.

The Ministry for the Environment aims to improve the management and environmental performance of domestic on-site wastewater systems to reduce the risks to human health and the environment. This discussion document assesses different policy options for improving the management and environmental performance of on-site systems, such as using non-regulatory measures, amending existing legislation, developing a national policy statement, and developing a national environmental standard.

The discussion focuses on a national environmental standard (the proposed standard) as the preferred option to achieve the objective. In essence, the proposed standard is that:

Owners of properties with on-site wastewater systems in specific locations will be required to hold a current warrant of fitness that confirms their on-site system is functioning properly and is being maintained to an appropriate standard.

The proposed standard would authorise regional councils to implement a scheme that requires property owners with an on-site system to hold a current warrant of fitness (WOF) for their system. To obtain a WOF, a system will be required to pass an inspection. Inspections will be carried out every three years.

The proposed standard would apply to domestic on-site systems that are operated as permitted activities under rules in regional plans. However, your views are sought on whether the proposed standard should include other systems, such as commercial on-site systems or systems covered by a resource consent.

The application of the proposed standard to every property in New Zealand with an on-site wastewater system was considered. However, council experience shows that the cumulative effects of multiple systems or systems in high-risk or sensitive areas are the ones that generally lead to health risks and environmental degradation. Also, an initial cost−benefit assessment indicated that the costs of applying a proposed standard to every domestic home that relies on an on-site system would significantly outweigh any potential benefits. Applying a standard to 'everyone everywhere' would create significant pressures on local government resources and would mean that only limited resources could be focused on the problem areas.

The refined proposal would target areas that have known problems with the performance of on-site systems, or where there is an actual or potential risk to the environment from higher densities of on-site systems.

A national environmental standard is a legally enforceable regulation. The exact wording of any standard will be drafted by Parliamentary Counsel if, after public submissions,, the Minister for the Environment decides to recommend to the Governor-General that a standard be made. This discussion document provides more detail on the proposed subject matter of the standard to help people prepare formal submissions.

Any person can make a submission on the proposed standard.

Submissions must be received by the Ministry for the Environment no later than 5.00pm on 26 September 2008.

Further details on making a submission are included in section 8.