Skip to main content
Critical alert


Together, we can stop the spread! For the latest updates and resources, visit the Government’s dedicated website:

Close alert

3.5.9 Implementation Methods - Tracer Discharges Permitted Activity Rule – Discharge of Dye and Salt Tracers

The discharge of dye and salt tracer material, excluding radioisotope tracers, into water is a permitted activity subject to the following conditions:

  1. The dye or salt tracer material discharged shall not exceed 20 litres of dye in solution or 10 kilograms of salt or 100 litres of salt solution.
  2. Waikato Regional Council and the relevant territorial authority shall be notified, in writing, of the proposed discharge at least 24 hours before the discharge. Such notification shall include:
    1. persons responsible for the discharge including contact details
    2. purpose of the tracer programme
    3. description of the tracer programme
    4. nature of the tracer (i.e. type, colour, product name/description)
    5. discharge location and timing
    6. duration of discharge.
  3. There shall be no discharge to any Significant Geothermal Feature.
  4. The dye or salt tracer material shall not be a hazardous substance in terms of the Hazardous Substances and New Organisms Act 1996.

Advisory Note:

  • Tracer discharges that are undertaken in accordance with s330 of the RMA are exempt from this Rule.
  • Significant Geothermal Features are defined in the Glossary, and in Development and Limited Development Geothermal Systems, identified on maps in Section 7.10 of this Plan. Discretionary Activity Rule – Discharge of Tracer Materials

The discharge of tracer material to water which does not comply with Rule is a discretionary activity (requiring resource consent).

Advisory Note:

  • Information requirements to enable the assessment of any application under this Rule are as set out in Section of this Plan. In addition, assessment shall also take into account the matters identified in the policies of Section 3.2.3 of this Plan.

Explanation and Principal Reasons for Adopting Methods and
Section 15 of the RMA restricts the discharge of contaminants into water unless the discharge is expressly allowed by a rule in a regional plan or by a resource consent. Dye and tracer materials that are non-toxic or inert generally do not have adverse environmental effects. In accordance with Policy 1, Rule therefore allows the discharge of dye and salt tracers into water bodies provided certain conditions are met including ecotoxicity levels and the quantity of tracer used. The Rule encourages the use of non-toxic tracers instead of tracers that are toxic or carcinogenic.

With regard to Rule, there are several tracers that have the potential to cause adverse environmental effects. Radioisotopes, for example, are recognised as having an associated radioactive hazard. Other dyes or tracers which may have toxic or carcinogenic* effects include organic compounds such as pesticides, or microbial tracers e.g. some viruses. Dyes range in toxicological concern. It is illegal for example, to use Rhodamine B as a water tracer in the United States whereas Rhodamine WT is relatively safe. For these reasons Rule provides for the discharge of all other tracer materials to water bodies to be assessed as discretionary activities.

<< Previous 


 Next >>