Onsite disposal of wastewater

This guidance explains the legislation that covers the design and installation of on-site wastewater disposal systems.

This information was confirmed as current in February 2016. It originally appeared in Codewords newsletters prior to January 2014.

  • Published on 1 June 2011
  • Of interest to Building owners, Drainlayers, Building consent authorities, Builders, Designers
  • 1st edition

Wastewater, called ‘foul water’ in the Building Code, is the discharge from sanitary fixtures and appliances in buildings.

The design and installation of on-site wastewater treatment and disposal systems has to comply with all of the following legislation:

  • Building Act 2004
    • comply with the Building Code specifically clauses G13 Foul Water, performance criteria G13.3.4
    •  installed in accordance with a building consent
  • Resource Management Act 1991
    • comply with the requirements of the District Plan (and Regional Plan if one exists)
    • resource consent may be required
  • Plumbers Gasfitters and Drainlayers Act 2006
    • installation is required to be undertaken by, or supervised by, a certifying drainlayer.

Some regional councils get involved in specifying the design and construction of on-site wastewater systems by specifying the publication to be used for its design. For example, Auckland Regional Council evaluates, as an alternative solution, the design of on-site wastewater disposal systems to TP58 On-site Wastewater Systems: Design and Management Manual, Third Edition. Other councils use AS/NZS 1547:2000 On-site Domestic-Wastewater Management.

Building Act and Resource Management Act - Comparison of requirements for on-site wastewater systems

  Building Act Resource Management Act
Must comply with Building Code (specifically G13.3.4) District Plan (or in some cases the Regional Plan)
Region of application Nationally District or city level for District Plans and regional level for the Regional Plans
Consent requirements Building Consent required for the design and installation Resource Consent if required by the District or Regional Plan.
May be a permitted activity under the District plan, which does not require a Resource Consent.
Means of complying G13/VM4 which cites AS/NZS 1547 (Part 4 Means of Compliance) Stipulated in the District Plan (or in some cases Regional Plan)
Common means of compliance AS/NZS 1547 (Part 4)
TP58 (as an alternative solution)
AS/NZS 1547

Note: the installation of on-site disposal systems must be undertaken or supervised by a certified drainlayer.

All guidance related to G13 Foul water

This information is published by the Ministry of Business, Innovation and Employment’s Chief Executive. It is a general guide only and, if used, does not relieve any person of the obligation to consider any matter to which the information relates according to the circumstances of the particular case. Expert advice may be required in specific circumstances. Where this information relates to assisting people: