The On-Site Effluent Treatment Regional Plan 2006 (OSET Plan) directs the management of domestic wastewater to protect water quality in the Bay of Plenty. On-site effluent treatment systems include septic tanks and associated soakage fields and advanced aerobic systems.

NOTE The new OSET provisions currently being developed for inclusion in the Regional Natural Resources Plan will eventually replace the On-Site Effluent Treatment Regional Plan.


In many parts of the Bay of Plenty, communities have been provided with sewers or reticulated wastewater systems. Where a sewer is available, you must connect. This is subject to the provisions of the Local Government Act 1974 section 459. Your District Council or City Council should be able to advise you if your area has been or is scheduled for reticulation.

There are maps of some areas where reticulation has been provided in the OSET Plan.

Further information about On-site effluent treatment systems

household water

On-site effluent treatment systems

Where no sewer is available you will need to provide an on site system which has been designed and constructed in accordance with the On-site Effluent Treatment Regional Plan. The purpose of the OSET Plan is to ensure that wastewater is discharged safely and that the effects are managed.

water data with binary digits

Approved OSET system designers

See a list of approved OSET system designers in the Bay of Plenty.

household water

Approved OSET effluent systems

Information about approved on site effluent systems.

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OSET maintenance zones

Some areas within the Bay of Plenty region have been deemed maintenance zones, and therefore have particular requirements. 

OSET system design training

On-site effluent treatment systems must be designed by a Suitably Qualified and Experienced Person (SQEP). To ensure the wastewater system is properly designed, we have developed a training course for system designers. 

The OSET system training course incorporates the following unit standards.

OSW Unit Standards






Demonstrate knowledge of domestic wastewater treatment processes




Describe domestic wastewater land application systems, and their selection, for site and soil characteristics




Demonstrate knowledge of hydraulics and pump types and fittings for on-site domestic wastewater treatment systems




Carry out a site and soil evaluation for an on-site domestic wastewater system




Design an on-site domestic wastewater system, and describe regulatory requirements




Describe package treatment, and wastewater land application systems



(NZQA; 2013)

We have contracted Opus Environmental Training Centre to deliver this course.  You can register your interest by visiting their website.

This course is currently on hold while it is being updated. Please register your interest for the next available course on the WSP on-site wastewater training website or phone Richard Rattray at WSP on 04 587 0694.

Some designers may already be qualified to undertake this work. If you think you are already qualified and want to use the “Recognition of Prior Learning RPL” process, contact NZWeta on the website above.


Contact Bay of Plenty Regional Council for:

  • Copies of the documents or maps.
  • Information on septic tank maintenance, nutrient management and reduction options.
  • Information on the proposed plan change process and provisions.


  • Jill Owen (Senior Planner) ph 0800 884 881 ext. 8229.

Contact your District or City Council for information on reticulated sewerage schemes:

  • Rotorua District Council (phone 07 348 4199).
  • Western Bay of Plenty District Council (phone 07 571 8008).
  • Whakatāne District Council (phone 07 306 0500).
  • Ōpōtiki District Council (phone 07 315 3030.